# Bumps documentation

## bumps.fitters

# Source code for bumps.fitters

    """
    Interfaces to various optimizers.
    """

    import sys
    import warnings
    from time import perf_counter

    import numpy as np

    from . import monitor
    from . import initpop
    from . import lsqerror

    from .history import History
    from .formatnum import format_uncertainty
    from .util import NDArray, format_duration

    # For typing
    from typing import List, Tuple, Dict, Any, Optional
    from numpy.typing import NDArray
    from h5py import Group
    from bumps.dream.state import MCMCDraw

    class ConsoleMonitor(monitor.TimedUpdate):
        """
        Display fit progress on the console
        """

        def __init__(self, problem, progress=1, improvement=30):
            monitor.TimedUpdate.__init__(self, progress=progress, improvement=improvement)
            self.problem = problem

        def _print_chisq(self, k, fx, final=False):
            print(f"step {k} cost {self.problem.chisq_str(nllf=fx)}{' [final]' if final else ''}")

        def _print_pars(self, x):
            p = self.problem.getp()
            try:
                self.problem.setp(x)
                print(self.problem.summarize())
            finally:
                self.problem.setp(p)

        def show_progress(self, history):
            self._print_chisq(history.step[0], history.value[0])
            sys.stdout.flush()

        def show_improvement(self, history):
            self._print_pars(history.point[0])
            sys.stdout.flush()

        def final(self, history: History, best: Dict[str, Any]):
            self._print_chisq(history.step[0], best["value"], final=True)
            self._print_pars(best["point"])
            print(f"time {format_duration(history.time[0])}")
            sys.stdout.flush()

        def info(self, message: str):
            print(message)
            sys.stdout.flush()

    class CheckpointMonitor(monitor.TimedUpdate):
        """
        Periodically save fit state so that it can be resumed later.
        """

        #: Function to call at each checkpoint.
        checkpoint = None  # type: Callable[None, None]

        def __init__(self, checkpoint, progress=60 * 30):
            monitor.TimedUpdate.__init__(self, progress=progress, improvement=np.inf)
            self.checkpoint = checkpoint
            self._first = True

        def show_progress(self, history):
            # Skip the first checkpoint since it only contains the
            # start/resume state
            if self._first:
                self._first = False
            else:
                self.checkpoint(history)

        def show_improvement(self, history):
            pass

    class StepMonitor(monitor.Monitor):
        """
        Collect information at every step of the fit and save it to a file.

        *fid* is the file to save the information to
        *fields* is the list of "step|time|value|point" fields to save

        The point field should be last in the list.
        """

        FIELDS = ["step", "time", "value", "point"]

        def __init__(self, problem, fid, fields=FIELDS):
            if any(f not in self.FIELDS for f in fields):
                raise ValueError("invalid monitor field")
            self.fid = fid
            self.fields = fields
            self.problem = problem
            self._pattern = "%%(%s)s\n" % (")s %(".join(fields))
            fid.write("# " + " ".join(fields) + "\n")

        def config_history(self, history):
            history.requires(time=1, value=1, point=1, step=1)

        def update(self, history):
            point = " ".join("%.15g" % v for v in history.point[0])
            time = "%g" % history.time[0]
            step = "%d" % history.step[0]
            value = "%.15g" % (self.problem.chisq(nllf=history.value[0]))
            out = self._pattern % dict(point=point, time=time, value=value, step=step)
            self.fid.write(out)

        __call__ = update

    class MonitorRunner(object):
        """
        Adaptor which allows solvers to accept progress monitors.

        The stopping() method manages checks for abort and timeout.
        """

        def __init__(self, monitors: List[monitor.Monitor], problem, abort_test=None, max_time=0.0):
            self.monitors = monitors
            self.history = History(time=1, step=1, point=1, value=1, population_points=1, population_values=1)
            # Pre-populate history.time so we can call stopping() before the first update.
            self.history.update(time=0.0)
            for M in self.monitors:
                M.config_history(self.history)
            self._start = perf_counter()
            self.max_time = max_time
            self.abort_test = abort_test if abort_test is not None else lambda: False

        def update(
            self,
            step: int,
            point: NDArray,
            value: float,
            population_points: Optional[NDArray] = None,
            population_values: Optional[NDArray] = None,
        ):
            # Note: DEFit doesn't use MonitorRunner for config/update
            self.history.update(
                time=perf_counter() - self._start,
                step=step,
                point=point,
                value=value,
                population_points=population_points,
                population_values=population_values,
            )
            for M in self.monitors:
                M(self.history)

        __call__ = update

        def stopping(self):
            return self.abort_test() or (self.history.time[0] >= self.max_time > 0)

        def info(self, message: str):
            for M in self.monitors:
                monitor_message = getattr(M, "info", None)
                if monitor_message is not None:
                    monitor_message(message)

        def final(self, point: NDArray, value: float):
            best = dict(point=point, value=value)
            for M in self.monitors:
                monitor_final = getattr(M, "final", None)
                if monitor_final is not None:
                    monitor_final(self.history, best)

    class FitBase(object):
        """
        FitBase defines the interface from bumps models to the various fitting
        engines available within bumps.

        Each engine is defined in its own class with a specific set of attributes
        and methods.

        The *name* attribute is the name of the optimizer.  This is just a simple
        string.

        The *settings* attribute is a list of pairs (name, default), where the
        names are defined as fields in FitOptions.  A best attempt should be
        made to map the fit options for the optimizer to the standard fit options,
        since each of these becomes a new command line option when running
        bumps.  If that is not possible, then a new option should be added
        to FitOptions.  A plugin architecture might be appropriate here, if
        there are reasons why specific problem domains might need custom fitters,
        but this is not yet supported.

        Each engine takes a fit problem in its constructor.

        The :meth:`solve` method runs the fit.  It accepts a
        monitor to track updates, a mapper to distribute work and
        key-value pairs defining the settings.

        There are a number of optional methods for the fitting engines.  Basically,
        all the methods in :class:`FitDriver` first check if they are specialized
        in the fit engine before performing a default action.

        The *load*/*save* methods load and save the fitter state in a given
        directory with a specific base file name.  The fitter can choose a file
        extension to add to the base name.  Some care is needed to be sure that
        the extension doesn't collide with other extensions such as .mon for
        the fit monitor.

        The *plot* method shows any plots to help understand the performance of
        the fitter, such as a convergence plot showing the the range of values
        in the population over time, as well as plots of the parameter uncertainty
        if available.  The plot should work within  is given a figure canvas to work with

        The *stderr*/*cov* methods should provide summary statistics for the
        parameter uncertainties.  Some fitters, such as MCMC, will compute these
        directly from the population.  Others, such as BFGS, will produce an
        estimate of the uncertainty as they go along.  If the fitter does not
        provide these estimates, then they will be computed from numerical
        derivatives at the minimum in the FitDriver method.
        """

        name: str
        """Display name for the fit method"""
        id: str
        """Short name for the fit method, used as --id on the command line."""
        # TODO: Replace list of tuples with an ordered dictionary?
        settings: List[Tuple[str, Any]]
        """Available fitting options and their default values."""
        state: Any = None
        """
        Internal fit state. If the state object has a draw method this should return
        a set of points from the posterior probability distribution for the fit.
        """

        def __init__(self, problem):
            """Fit the models and show the results"""
            self.problem: "bumps.fitproblem.FitProblem" = problem

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            raise NotImplementedError()

        @staticmethod
        def h5dump(group: "Group", state: Any) -> None:
            """
            Store fitter.state into the given HDF5 Group.

            This will be restored by the corresponding h5load, then passed
            to the fitter to resume from its current state. This strategy
            is particularly useful for MCMC analysis where you may need more
            iterations for the chains to reach equilibrium.  It is also the
            basis of checkpoint/restore operations for fitters such as de
            and amoeba which manage a population, though in those cases the
            best point seen so far may be good enough.
            """
            # Default is nothing to save because resume isn't supported for the fitter
            ...

        @staticmethod
        def h5load(group: "Group") -> Any:
            """
            Load internal fit state from the group saved by h5dump. Note that
            this function will be responsible for migrating state from older
            versions to newer versions of the saved representation.
            """
            return None

    class MultiStart(FitBase):
        """
        Multi-start monte carlo fitter.

        This fitter wraps a local optimizer, restarting it a number of times
        to give it a chance to find a different local minimum.  If the jump
        radius is non-zero, then restart near the best fit, otherwise restart at
        random.
        """

        name = "Multistart Monte Carlo"
        settings = [("starts", 100), ("jump", 0.0)]

        def __init__(self, fitter):
            FitBase.__init__(self, fitter.problem)
            self.fitter = fitter

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            starts = max(options.pop("starts", 1), 1)
            jump = options.pop("jump", 0.0)
            x_best, f_best, chisq_best = None, np.inf, None
            for k in range(starts):
                x, fx = self.fitter.solve(monitors=monitors, mapper=mapper, **options)
                chisq = self.problem.chisq_str(nllf=fx)
                if fx < f_best:
                    x_best, f_best, chisq_best = x, fx, chisq
                    monitors.info(f"fit {k+1} of {starts}: {chisq} [new best]")
                else:
                    monitors.info(f"fit {k+1} of {starts}: {chisq} [best={chisq_best}]")
                if k >= starts - 1 or monitors.stopping():
                    break
                if jump == 0.0:
                    self.problem.randomize()
                else:
                    pop = initpop.eps_init(1, x_best, self.problem.bounds(), use_point=False, eps=jump)
                    self.problem.setp(pop[0])
                # print(f"jump={jump} moving from {x} to {self.problem.getp()}")
            return x_best, f_best

    class DEFit(FitBase):
        """
        Classic Storn and Price differential evolution optimizer.
        """

        name = "Differential Evolution"
        id = "de"
        settings = [
            ("steps", 1000),
            ("pop", 10),
            ("CR", 0.9),
            ("F", 2.0),
            ("ftol", 1e-8),
            ("xtol", 1e-6),  # ('stop', ''),
        ]
        state = None

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            options = _fill_defaults(options, self.settings)
            from .mystic.optimizer import de
            from .mystic.solver import Minimizer
            from .mystic import stop

            if mapper is not None:
                _mapper = lambda p, v: mapper(v)
            else:
                _mapper = lambda p, v: list(map(self.problem.nllf, v))
            resume = self.state is not None
            steps = options["steps"] + (self.state["step"][-1] if resume else 0)
            strategy = de.DifferentialEvolution(
                npop=options["pop"], CR=options["CR"], F=options["F"], crossover=de.c_bin, mutate=de.rand1u
            )
            success = parse_tolerance(options)
            failure = stop.Steps(steps)
            # Step adds to current step number if resume
            minimize = Minimizer(
                strategy=strategy,
                problem=self.problem,
                # TODO: use MonitorRunner update within DE
                history=monitors.history,
                monitors=monitors.monitors,
                success=success,
                failure=failure,
            )
            if self.state is not None:
                monitors.history.restore(self.state)
            x = minimize(mapper=_mapper, abort_test=monitors.stopping, resume=resume)
            self.state = monitors.history.snapshot()
            # print("final de state", self.state)
            # print(minimize.termination_condition())
            # with open("/tmp/evals","a") as fid:
            #   print >>fid,minimize.history.value[0],minimize.history.step[0],\
            #       minimize.history.step[0]*options['pop']*len(self.problem.getp())
            return x, monitors.history.value[0]

        def load(self, input_path):
            self.state = _de_load_history(input_path)

        def save(self, output_path):
            _de_save_history(output_path, self.state)

        @staticmethod
        def h5load(group: Group) -> Any:
            from .webview.server.state_hdf5_backed import read_json

            return read_json(group, "DE_history")

        @staticmethod
        def h5dump(group: Group, state: Dict[str, Any]):
            from .webview.server.state_hdf5_backed import write_json

            write_json(group, "DE_history", state)

    def parse_tolerance(options):
        from .mystic import stop

        if options.get("stop", ""):
            return stop.parse_condition(options["stop"])

        xtol, ftol = options["xtol"], options["ftol"]
        if xtol == 0:
            if ftol == 0:
                return None
            if ftol < 0:
                return stop.Rf(-ftol, scaled=True)
            return stop.Rf(ftol, scaled=False)
        else:
            if xtol == 0:
                return None
            if xtol < 0:
                return stop.Rx(-xtol, scaled=True)
            return stop.Rx(xtol, scaled=False)

    def _de_history_file(path):
        return path + "-history.json"

    def _de_load_history(path):
        """
        Load fitter details from a history file.
        """
        import json

        with open(_de_history_file(path), "r") as fid:
            return json.load(fid)

    def _de_save_history(path, state):
        """
        Save fitter details to a history file as JSON.

        The content of the details are fitter specific.
        """
        import json

        with open(_de_history_file(path), "w") as fid:
            json.dump(state, fid)

    class BFGSFit(FitBase):
        """
        BFGS quasi-newton optimizer.

        BFGS estimates Hessian and its Cholesky decomposition, but initial
        tests give uncertainties quite different from the directly computed
        Jacobian in Levenburg-Marquardt or the Hessian estimated at the
        minimum by numerical differentiation.

        To use the internal 'H' and 'L' and save some computation time, then
        use::

            C = lsqerror.chol_cov(fit.result['L'])
            stderr = lsqerror.stderr(C)
        """

        name = "Quasi-Newton BFGS"
        id = "newton"
        settings = [("steps", 3000), ("ftol", 1e-6), ("xtol", 1e-12), ("starts", 1), ("jump", 0.0)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            options = _fill_defaults(options, self.settings)
            from .quasinewton import quasinewton

            def update(step, x, fx):
                monitors(step=step, point=x, value=fx, population_points=[x], population_values=[fx])
                return not monitors.stopping()

            result = quasinewton(
                fn=self.problem.nllf,
                x0=self.problem.getp(),
                monitor=update,
                itnlimit=options["steps"],
                gradtol=options["ftol"],
                steptol=1e-12,
                macheps=1e-8,
                eta=1e-8,
            )
            self.result = result
            # code = result['status']
            # from .quasinewton import STATUS
            # print("%d: %s, x=%s, fx=%s"
            #      % (code, STATUS[code], result['x'], result['fx']))
            return result["x"], result["fx"]

    class PSFit(FitBase):
        """
        Particle swarm optimizer.
        """

        name = "Particle Swarm"
        id = "ps"
        settings = [("steps", 3000), ("pop", 1)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            from .random_lines import particle_swarm

            options = _fill_defaults(options, self.settings)
            if mapper is None:
                mapper = lambda x: list(map(self.problem.nllf, x))

            def update(step, x, fx, k):
                monitors(step=step, point=x[:, k], value=fx[k], population_points=x.T, population_values=fx)
                return not monitors.stopping()

            low, high = self.problem.bounds()
            cfo = dict(
                parallel_cost=mapper,
                n=len(low),
                x0=self.problem.getp(),
                x1=low,
                x2=high,
                f_opt=0,
                monitor=update,
            )
            npop = int(cfo["n"] * options["pop"])

            result = particle_swarm(cfo, npop, maxiter=options["steps"])
            satisfied_sc, n_feval, f_best, x_best = result

            return x_best, f_best

    class RLFit(FitBase):
        """
        Random lines optimizer.
        """

        name = "Random Lines"
        id = "rl"
        settings = [("steps", 3000), ("pop", 0.5), ("CR", 0.9), ("starts", 20), ("jump", 0.0)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            from .random_lines import random_lines

            options = _fill_defaults(options, self.settings)
            if mapper is None:
                mapper = lambda x: list(map(self.problem.nllf, x))

            def update(step, x, fx, k):
                monitors(step=step, point=x[:, k], value=fx[k], population_points=x.T, population_values=fx)
                return not monitors.stopping()

            low, high = self.problem.bounds()
            cfo = dict(
                parallel_cost=mapper,
                n=len(low),
                x0=self.problem.getp(),
                x1=low,
                x2=high,
                f_opt=0,
                monitor=update,
            )
            npop = max(int(cfo["n"] * options["pop"]), 3)

            result = random_lines(cfo, npop, maxiter=options["steps"], CR=options["CR"])
            satisfied_sc, n_feval, f_best, x_best = result

            return x_best, f_best

    class PTFit(FitBase):
        """
        Parallel tempering optimizer.
        """

        name = "Parallel Tempering"
        id = "pt"
        settings = [("steps", 400), ("nT", 24), ("CR", 0.9), ("burn", 100), ("Tmin", 0.1), ("Tmax", 10.0)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            options = _fill_defaults(options, self.settings)
            # TODO: no mapper??
            from .partemp import parallel_tempering

            def update(step, x, fx, P, E):
                monitors(step=step, point=x, value=fx, population_points=P, population_values=E)
                return not monitors.stopping()

            t = np.logspace(np.log10(options["Tmin"]), np.log10(options["Tmax"]), options["nT"])
            history = parallel_tempering(
                nllf=self.problem.nllf,
                p=self.problem.getp(),
                bounds=self.problem.bounds(),
                # logfile="partemp.dat",
                T=t,
                CR=options["CR"],
                steps=options["steps"],
                burn=options["burn"],
                monitor=update,
            )
            return history.best_point, history.best

    class SimplexFit(FitBase):
        """
        Nelder-Mead simplex optimizer.
        """

        name = "Nelder-Mead Simplex"
        id = "amoeba"
        settings = [("steps", 1000), ("radius", 0.15), ("xtol", 1e-6), ("ftol", 1e-8), ("starts", 1), ("jump", 0.01)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            from .simplex import simplex

            options = _fill_defaults(options, self.settings)

            # TODO: no mapper??
            # print("bounds", self.problem.bounds())
            def update(k, n, x, fx):
                monitors(step=k, point=x[0], value=fx[0], population_points=x, population_values=fx)

            result = simplex(
                f=self.problem.nllf,
                x0=self.problem.getp(),
                bounds=self.problem.bounds(),
                abort_test=monitors.stopping,
                update_handler=update,
                maxiter=options["steps"],
                radius=options["radius"],
                xtol=options["xtol"],
                ftol=options["ftol"],
            )
            # Let simplex propose the starting point for the next amoeba
            # fit in a multistart amoeba context.  If the best is always
            # used, the fit can get stuck in a local minimum.
            self.problem.setp(result.next_start)
            # print("amoeba %s %s"%(result.x,result.fx))
            return result.x, result.fx

    class MPFit(FitBase):
        """
        MPFit optimizer.
        """

        name = "Levenberg-Marquardt"
        id = "lm"
        settings = [("steps", 200), ("ftol", 1e-10), ("xtol", 1e-10), ("starts", 1), ("jump", 0.0)]

        def solve(self, monitors=None, mapper=None, **options):
            from .mpfit import mpfit

            options = _fill_defaults(options, self.settings)
            self._low, self._high = self.problem.bounds()
            self._stopping = monitors.stopping
            x0 = self.problem.getp()
            parinfo = []
            for low, high in zip(*self.problem.bounds()):
                parinfo.append(
                    {
                        #'value': None,  # passed in by xall instead
                        #'fixed': False,  # everything is varying
                        "limited": (np.isfinite(low), np.isfinite(high)),
                        "limits": (low, high),
                        #'parname': '',  # could probably ask problem for this...
                        # From the code, default step size is sqrt(eps)*abs(value)
                        # or eps if value is 0.  This seems okay.  The other
                        # other alternative is to limit it by bounds.
                        #'step': 0,  # compute step automatically
                        #'mpside': 0,  # 1, -1 or 2 for right-, left- or 2-sided deriv
                        #'mpmaxstep': 0.,  # max step for this parameter
                        #'tied': '',  # parameter expressions tying fit parameters
                        #'mpprint': 1,  # print the parameter value when iterating
                    }
                )

            def update(fcn, p, k, fnorm, functkw=None, parinfo=None, quiet=0, dof=None, **extra):
                # The mpfit residuals are set up so that fnorm = sumsq residuals = 2*nllf.
                monitors(step=k, point=p, value=fnorm / 2)
                if monitors.stopping():
                    return -1

            result = mpfit(
                fcn=self._residuals,
                xall=x0,
                parinfo=parinfo,
                autoderivative=True,
                fastnorm=True,
                double=0,  # use single precision machine epsilon for derivative step
                # damp=0,  # no damping when damp=0
                # Stopping conditions
                ftol=options["ftol"],
                xtol=options["xtol"],
                # gtol=1e-100, # exclude gtol test
                maxiter=options["steps"],
                # Progress monitor
                iterfunct=update,
                nprint=1,  # call monitor each iteration
                quiet=True,  # leave it to monitor to print any info
                # Returns values
                nocovar=True,  # use our own covar calculation for consistency
            )
            # Note that result.perror contains dx and result.covar contains cov.
            # See mpfit.py:781 for status codes. We are returning -1 for user abort.
            if result.status > 0 or result.status == -1:
                x = result.params
                # TODO: mpfit sometimes returns root chisq and sometimes chisq
                # Use nllf() as the resulting cost function for consistency with other fitters.
                # Should be able to use fnorm/2 but it is broken in mpfit.
                if not (self.problem.getp() == x).all():
                    self.problem.setp(x)
                fx = self.problem.nllf()
            else:
                x, fx = None, None

            return x, fx

        def _residuals(self, p, fjac=None):
            # # Returning -1 here stops immediately rather than completing the step. This is
            # # different from the other fitters, which wait for the step to complete.
            # if self._stopping():
            #     return -1, None

            # Evaluating with new data point so update
            self.problem.setp(p)

            # Tally costs for residuals and broken constraints. Treat prior probabilities on
            # the parameters and broken constraints as additional measurements. The result
            # should be that fnorm = sumsq residuals = 2 * nllf
            extra_cost, failing_constraints = self.problem.constraints_nllf()
            residuals = np.hstack((self.problem.residuals().flat, self.problem.parameter_residuals(), np.sqrt(extra_cost)))
            # print("sumsq resid", np.sum(residuals**2), "nllf", self.problem.nllf()*2)

            # # Spread the cost over the residuals.  Since we are smoothly increasing
            # # residuals as we leave the boundary, this should push us back into the
            # # boundary (within tolerance) during the lm fit.
            # residuals += np.sign(residuals) * (extra_cost / len(residuals))
            return 0, residuals

    class LevenbergMarquardtFit(FitBase):
        """
        Levenberg-Marquardt optimizer.
        """

        name = "Levenberg-Marquardt (scipy.leastsq)"
        id = "scipy.leastsq"
        settings = [("steps", 200), ("ftol", 1.5e-8), ("xtol", 1.5e-8)]
        # LM also has
        #    gtol: orthoganality between jacobian columns
        #    epsfcn: numerical derivative step size
        #    factor: initial radius
        #    diag: variable scale factors to bring them near 1

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            from scipy import optimize

            options = _fill_defaults(options, self.settings)
            self._low, self._high = self.problem.bounds()
            x0 = self.problem.getp()
            maxfev = options["steps"] * (len(x0) + 1)
            monitors(step=0, point=x0, value=self.problem.nllf())
            result = optimize.leastsq(
                self._bounded_residuals,
                x0,
                ftol=options["ftol"],
                xtol=options["xtol"],
                maxfev=maxfev,
                epsfcn=1e-8,
                full_output=True,
            )
            x, cov_x, info, mesg, success = result
            if not 1 <= success <= 4:
                # don't treat "reached maxfev" as a true failure
                if "reached maxfev" in mesg:
                    # unless the x values are bad
                    if not np.all(np.isfinite(x)):
                        x = None
                        mesg = "Levenberg-Marquardt fit failed with bad values"
                else:
                    x = None
            self._cov = cov_x if x is not None else None
            # compute one last time with x forced inside the boundary, and using
            # problem.nllf as returned by other optimizers.  We will ignore the
            # covariance output and calculate it again ourselves.  Not ideal if
            # f is expensive, but it will be consistent with other optimizers.
            if x is not None:
                x += self._stray_delta(x)
                self.problem.setp(x)
                fx = self.problem.nllf()
            else:
                fx = None
            monitors(step=1, point=x, value=self.problem.nllf())
            return x, fx

        def _bounded_residuals(self, p):
            # Force the fit point into the valid region
            stray = self._stray_delta(p)
            stray_cost = np.sum(stray**2)
            if stray_cost > 0:
                stray_cost += 1e6
            self.problem.setp(p + stray)
            # treat prior probabilities on the parameters as additional
            # measurements
            residuals = np.hstack((self.problem.residuals().flat, self.problem.parameter_residuals()))
            # Tally costs for straying outside the boundaries plus other costs
            constraints_cost, failing_constraints = self.problem.constraints_nllf()
            extra_cost = stray_cost + constraints_cost
            # Spread the cost over the residuals.  Since we are smoothly increasing
            # residuals as we leave the boundary, this should push us back into the
            # boundary (within tolerance) during the lm fit.
            residuals += np.sign(residuals) * (extra_cost / len(residuals))
            return residuals

        def _stray_delta(self, p):
            """calculate how far point is outside the boundary"""
            return np.where(p < self._low, self._low - p, 0) + np.where(p > self._high, self._high - p, 0)

        def cov(self):
            return self._cov

    class SnobFit(FitBase):
        name = "SNOBFIT"
        id = "snobfit"
        settings = [("steps", 200)]

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            options = _fill_defaults(options, self.settings)
            # TODO: no mapper??
            from snobfit.snobfit import snobfit

            def update(k, x, fx, improved):
                # TODO: snobfit does have a population...
                monitors(step=k, point=x, value=fx, population_points=[x], population_values=[fx])

            x, fx, _ = snobfit(self.problem, self.problem.getp(), self.problem.bounds(), fglob=0, callback=update)
            return x, fx

    class DreamModel:
        """
        DREAM wrapper for fit problems. Implements dream.core.Model protocol.
        """

        labels: List[str]
        bounds: NDArray

        def __init__(self, problem=None, mapper=None):
            """
            Create a sampling from the multidimensional likelihood function
            represented by the problem set using dream.
            """
            # print "dream"
            self.problem = problem
            self.bounds = self.problem.bounds()
            self.labels = self.problem.labels()

            self.mapper = mapper if mapper else lambda p: list(map(self.nllf, p))

        def map(self, pop):
            # print "calling mapper",self.mapper
            return -np.array(self.mapper(pop))

    class DreamFit(FitBase):
        name = "DREAM"
        id = "dream"
        settings = [
            ("samples", int(1e4)),
            ("burn", 100),
            ("pop", 10),
            ("init", "eps"),
            ("thin", 1),
            ("alpha", 0.0),
            ("outliers", "iqr"),
            ("trim", False),
            ("steps", 0),  # deprecated: use --samples instead
        ]

        def __init__(self, problem):
            FitBase.__init__(self, problem)
            self.state = None

        def solve(self, monitors: MonitorRunner, mapper=None, **options):
            from .dream import Dream

            options = _fill_defaults(options, self.settings)

            def update(state, pop, logp):
                # Get an early copy of the state
                self.state = monitors.history.fit_state = state
                step = state.generation
                x, fx = state.best()
                monitors(step=step, point=x, value=-fx, population_points=pop, population_values=-logp)
                return True

            population = initpop.generate(self.problem, **options)
            pop_size = population.shape[0]
            draws, steps = int(options["samples"]), options["steps"]
            if steps == 0:
                steps = (draws + pop_size - 1) // pop_size
            monitors.info(f"# burn: {options['burn']} # steps: {steps}, # draws: {pop_size * steps}")
            population = population[None, :, :]
            # print(f"Running dream with {population.shape=} {pop_size=} {steps=}")
            sampler = Dream(
                model=DreamModel(self.problem, mapper),
                population=population,
                draws=pop_size * steps,
                burn=pop_size * options["burn"],
                thinning=options["thin"],
                monitor=update,
                alpha=options["alpha"],
                outlier_test=options["outliers"],
                DE_noise=1e-6,
            )

            self.state = sampler.sample(state=self.state, abort_test=monitors.stopping)
            # print("<<< Dream is done sampling >>>")

            # If "trim" option is enabled, automatically set the portion, otherwise use
            # the default 100% that was set at the start of sampler.sample.
            if options.get("trim", False):
                self.state.portion = self.state.trim_portion()
            # print("trimming", options['trim'], self._trimmed)
            self.state.mark_outliers()
            self.state.keep_best()
            self.state.title = self.problem.name

            # TODO: Add derived/visible/integer variable support to other optimizers.
            # TODO: Serialize derived/visible/integer variable support with fitproblem.
            # TODO: Use parameter expressions for derived vars rather than a function.
            # TODO: Allow fixed parameters as part of the derived variable function.
            fn, labels = getattr(self.problem, "derive_vars", (None, None))
            if fn is not None:
                self.state.set_derived_vars(fn, labels=labels)
            visible_vars = getattr(self.problem, "visible_vars", None)
            if visible_vars is not None:
                self.state.set_visible_vars(visible_vars)
            integer_vars = getattr(self.problem, "integer_vars", None)
            if integer_vars is not None:
                self.state.set_integer_vars(integer_vars)

            x, fx = self.state.best()

            # Check that the last point is the best point
            # points, logp = self.state.sample()
            # assert logp[-1] == fx
            # print(points[-1], x)
            # assert all(points[-1, i] == xi for i, xi in enumerate(x))
            return x, -fx

        def entropy(self, **kw):
            return self.state.entropy(**kw)

        def stderr(self):
            """
            Approximate standard error as 1/2 the 68% interval fo the sample,
            which is a more robust measure than the mean of the sample for
            non-normal distributions.
            """
            from .dream.stats import var_stats

            vstats = var_stats(self.state.draw())
            return np.array([(v.p68[1] - v.p68[0]) / 2 for v in vstats], "d")

        # def cov(self):
        #    # Covariance estimate from final 1000 points
        #    return np.cov(self.state.draw().points[-1000:])

        def load(self, input_path):
            from .dream.state import load_state, path_contains_saved_state

            if path_contains_saved_state(input_path):
                print("loading saved state from %s (this might take awhile) ..." % (input_path,))
                fn, labels = getattr(self.problem, "derive_vars", (None, []))
                self.state = load_state(input_path, report=100, derived_vars=len(labels))
            else:
                # Warn if mc files are not found on --resume path
                warnings.warn("No mcmc found; ignoring --resume=%r" % input_path)

        def save(self, output_path):
            self.state.save(output_path)

        @staticmethod
        def h5load(group: Group) -> MCMCDraw:
            from .dream.state import h5load

            return h5load(group)

        @staticmethod
        def h5dump(group: Group, state: MCMCDraw):
            from .dream.state import h5dump

            h5dump(group, state)

        def plot(self, output_path):
            self.state.show(figfile=output_path)
            self.error_plot(figfile=output_path)

        def show(self):
            pass

        def error_plot(self, figfile):
            # Produce error plot
            import pylab
            from . import errplot

            # TODO: shouldn't mix calc and display!
            points = errplot.error_points_from_state(self.state)
            res = errplot.calc_errors(self.problem, points)
            if res is not None:
                pylab.figure()
                errplot.show_errors(res)
                pylab.savefig(figfile + "-errors.png", format="png")

    class Resampler(FitBase):
        # TODO: why isn't cli.resynth using this?

        def __init__(self, fitter):
            self.fitter = fitter
            raise NotImplementedError()

        def solve(self, **options):
            starts = options.pop("starts", 1)
            restart = options.pop("restart", False)
            x, fx = self.fitter.solve(**options)
            points = _resampler(self.fitter, x, samples=starts, restart=restart, **options)
            self.points = points  # save points for later plotting
            return x, fx

    def _resampler(fitter, xinit, samples=100, restart=False, **options):
        """
        Refit the result multiple times with resynthesized data, building
        up an array in Result.samples which contains the best fit to the
        resynthesized data.  *samples* is the number of samples to generate.
        *fitter* is the (local) optimizer to use. **kw are the parameters
        for the optimizer.
        """
        x = xinit
        points = []
        try:  # TODO: some solvers already catch KeyboardInterrupt
            for _ in range(samples):
                # print "== resynth %d of %d" % (i, samples)
                fitter.problem.resynth_data()
                if restart:
                    fitter.problem.randomize()
                else:
                    fitter.problem.setp(x)
                x, fx = fitter.solve(**options)
                points.append(np.hstack((fx, x)))
                # print self.problem.summarize()
                # print "[chisq=%.2f]" % self.problem.chisq(nllf=fx))
        except KeyboardInterrupt:
            # On keyboard interrupt we can declare that we are finished sampling
            # without it being an error condition, so let this exception pass.
            pass
        finally:
            # Restore the state of the problem
            fitter.problem.restore_data()
            fitter.problem.setp(xinit)
        return points

    class FitDriver(object):
        def __init__(self, fitclass=None, problem=None, monitors=None, abort_test=None, mapper=None, time=0.0, **options):
            self.fitclass = fitclass
            self.problem = problem
            self.options = options
            self.monitors = [ConsoleMonitor(problem)] if monitors is None else monitors
            self.max_time = time * 3600  # Timeout converted from hours to seconds.
            self.abort_test = abort_test
            self.mapper = mapper if mapper else lambda p: list(map(problem.nllf, p))
            self.fitter = None
            self.result = None
            self._reset_cache()

        def _reset_cache(self):
            """
            Cached values. Deleted by fit() to force recomputation when the new fit is complete.
            """
            self._cov = None
            self._stderr = None
            self._stderr_from_cov = None
            self._chisq = None

        def fit(self, resume=None, fit_state=None):
            """
            Providing *fit_state* allows the fit to resume from a previous state. If None
            then the fit will be started from a clean state.

            The *fitclass* object should provide static methods for *h5dump/h5load* for
            saving and loading the internal state of the fitter to a specific group in an
            hdf5 file. The result of *h5load(group)* can be passed as *fit_state* to resume a
            fit with whatever new options are provided. It is up to the fitter to decide
            how to interpret this. The state can be retrieved from state=driver.fitter.state
            at the end of the fit and saved using *h5dump(group, state)*.

            *resume* (= resume_path / problem.name) is used by the pre-1.0 command line
            interface to provide the base path for the fit state files. For dream this can
            be replaced by the following::

                fn, labels = getattr(problem, "derive_vars", (None, []))
                fit_state = load_state(input_path, report=100, derived_vars=len(labels))
            """
            self._reset_cache()

            # Awkward interface for dump/load state. The structure of the state depends on
            # the fit method, so we need to delegate dump/load to the Fitter class. However,
            # the fitter is not instantiated outside of the fit method, so dump/load must
            # be static methods on fitclass, with load called before the fit and dump after.
            # A further complication is checkpointing, which requires that the state be
            # available and up to date when the checkpoint is requested.
            fitter = self.fitclass(self.problem)
            fitter.state = fit_state
            if resume and hasattr(fitter, "load"):
                fitter.load(resume)
            starts = self.options.get("starts", 1)
            if starts > 1:
                fitter = MultiStart(fitter)
            # TODO: better interface for history management?
            # Keep a handle to the fitter which has state and monitor_runner which has history
            self.fitter = fitter
            self.monitor_runner = MonitorRunner(
                problem=self.problem, monitors=self.monitors, abort_test=self.abort_test, max_time=self.max_time
            )
            x, fx = fitter.solve(
                monitors=self.monitor_runner, abort_test=self.abort_test, mapper=self.mapper, **self.options
            )
            if x is not None:
                self.problem.setp(x)
            self.wall_time = self.monitor_runner.history.time[0]
            self.result = x, fx
            self.monitor_runner.final(point=x, value=fx)
            return x, fx

        def clip(self):
            """
            Force parameters within bounds so constraints are finite.

            The problem is updated with the new parameter values.

            Returns a list of parameter names that were clipped.
            """
            labels = self.problem.labels()
            values = self.problem.getp()
            bounds = self.problem.bounds()
            new_values = np.clip(values, bounds[0], bounds[1])
            clipped = [name for name, old, new in zip(labels, values, new_values) if old != new]
            self.problem.setp(new_values)
            return clipped

        def entropy(self, method=None):
            if hasattr(self.fitter, "entropy"):
                return self.fitter.entropy(method=method)
            else:
                from .dream import entropy

                return entropy.cov_entropy(self.cov()), 0

        def chisq(self):
            if self._chisq is None:
                self._chisq = self.problem.chisq()
            return self._chisq

        def cov(self):
            r"""
            Return an estimate of the covariance of the fit.

            Depending on the fitter and the problem, this may be computed from
            existing evaluations within the fitter, or from numerical
            differentiation around the minimum.

            If the problem uses $\chi^2/2$ as its nllf, then the covariance
            is derived from the Jacobian::

                x = fit.problem.getp()
                J = bumps.lsqerror.jacobian(fit.problem, x)
                cov = bumps.lsqerror.jacobian_cov(J)

            Otherwise, the numerical differentiation will use the Hessian
            estimated from nllf::

                x = fit.problem.getp()
                H = bumps.lsqerror.hessian(fit.problem, x)
                cov = bumps.lsqerror.hessian_cov(H)
            """
            # Note: if fit() has not been run then self.fitter is None and in
            # particular, self.fitter will not have a covariance matrix.  In
            # this case, the code will fall through to computing the covariance
            # matrix directly from the problem.  It will use the initial value
            # stored in the problem parameters because results will also be None.
            if self._cov is None and hasattr(self.fitter, "cov"):
                self._cov = self.fitter.cov()
                # print("fitter cov", self._cov)
            if self._cov is None:
                # Use Jacobian if residuals are available because it is faster
                # to compute.  Otherwise punt and use Hessian.  The has_residuals
                # attribute should be True if present.  It may be false if
                # the problem defines a residuals method but doesn't really
                # have residuals (e.g. to allow levenberg-marquardt to run even
                # though it is not fitting a sum-square problem).
                if hasattr(self.problem, "has_residuals"):
                    has_residuals = self.problem.has_residuals
                else:
                    has_residuals = hasattr(self.problem, "residuals")
                x = self.problem.getp() if self.result is None else self.result[0]
                if has_residuals:
                    J = lsqerror.jacobian(self.problem, x)
                    # print("Jacobian", J)
                    self._cov = lsqerror.jacobian_cov(J)
                else:
                    H = lsqerror.hessian(self.problem, x)
                    # print("Hessian", H)
                    self._cov = lsqerror.hessian_cov(H)
            return self._cov

        def stderr(self):
            """
            Return an estimate of the standard error of the fit.

            Depending on the fitter and the problem, this may be computed from
            existing evaluations within the fitter, or from numerical
            differentiation around the minimum.
            """
            # Note: if fit() has not been run then self.fitter is None and in
            # particular, self.fitter will not have a stderr method defined so
            # it will compute stderr from covariance.
            if self._stderr is None and hasattr(self.fitter, "stderr"):
                self._stderr = self.fitter.stderr()
            if self._stderr is None:
                # If no stderr from the fitter then compute it from the covariance
                self._stderr = self.stderr_from_cov()
            return self._stderr

        def stderr_from_cov(self):
            """
            Return an estimate of standard error of the fit from covariance matrix.

            Unlike stderr, which uses the estimate from the underlying
            fitter (DREAM uses the MCMC sample for this), *stderr_from_cov*
            estimates the error from the diagonal of the covariance matrix.
            Here, the covariance matrix may have been estimated by the fitter
            instead of the Hessian.
            """
            if self._stderr_from_cov is None:
                self._stderr_from_cov = lsqerror.stderr(self.cov())
            return self._stderr_from_cov

        def show(self):
            if hasattr(self.fitter, "show"):
                self.fitter.show()
            if hasattr(self.problem, "show"):
                self.problem.show()

        # TODO: reenable the "implied variance" calculation
        def _unused_show_err(self):
            """
            Display the error approximation from the numerical derivative.

            Warning: cost grows as the cube of the number of parameters.
            """
            # TODO: need cheaper uncertainty estimate
            # Note: error estimated from hessian diagonal is insufficient.
            err = self.stderr_from_cov()
            # TODO: citation needed
            # The "implied variance" column is obtained by scaling the covariance
            # matrix so that chisq = DOF. Any excess chisq implies increased
            # variance in the measurements, so increased variance in the parameters.
            # This is well defined for linear systems with equal but unknown
            # variance in each measurement, and assumed to be approximately true
            # for nonlinear systems, with the unexplained variance distributed
            # proportionately amongst the measurement uncertainties.
            norm = np.sqrt(self.chisq())
            print("=== Uncertainty from curvature:     name value(unc.)     value(unc./chi)) ===")
            for k, v, dv in zip(self.problem.labels(), self.problem.getp(), err):
                print("%40s %-15s %-15s" % (k, format_uncertainty(v, dv), format_uncertainty(v, dv / norm)))
            print("=" * 75)

        def show_err(self):
            """
            Display the error approximation from the numerical derivative.

            Warning: cost grows as the cube of the number of parameters.
            """
            # TODO: need cheaper uncertainty estimate
            # Note: error estimated from hessian diagonal is insufficient.
            err = self.stderr_from_cov()
            print("=== Uncertainty from curvature:     name   value(unc.) ===")
            for k, v, dv in zip(self.problem.labels(), self.problem.getp(), err):
                print(f"{k:>40s}   {format_uncertainty(v, dv):<15s}")
            print("=" * 58)

        def show_cov(self):
            cov = self.cov()
            maxn = 1000  # max array dims to print
            cov_str = np.array2string(
                cov,
                max_line_width=20 * maxn,
                threshold=maxn * maxn,
                precision=6,  # suppress_small=True,
                separator=", ",
            )
            print("=== Covariance matrix ===")
            print(cov_str)
            print("=========================")

        def show_entropy(self, method=None):
            print("Calculating entropy...")
            S, dS = self.entropy(method=method)
            print("Entropy: %s bits" % format_uncertainty(S, dS))

        def save(self, output_path):
            # print "calling driver save"
            if hasattr(self.fitter, "save"):
                self.fitter.save(output_path)
            if hasattr(self.problem, "save"):
                self.problem.save(output_path)

        def load(self, input_path):
            # print "calling driver save"
            if hasattr(self.fitter, "load"):
                self.fitter.load(input_path)
            if hasattr(self.problem, "load"):
                self.problem.load(input_path)

        def plot(self, output_path, view=None):
            # print "calling fitter.plot"
            if hasattr(self.problem, "plot"):
                self.problem.plot(figfile=output_path, view=view)
            if hasattr(self.fitter, "plot"):
                self.fitter.plot(output_path=output_path)

        def _save_fit_cov(self, output_path):
            model = getattr(self.problem, "name", self.problem.__class__.__name__)
            fitter = self.fitclass.id
            cov = self.cov()
            err = self.stderr_from_cov()
            chisq = self.chisq()

            state = {
                "model": model,
                "fitter": fitter,
            }

    def _fill_defaults(options, settings):
        """
        Returns options dict with missing values filled from settings.
        """
        result = dict(settings)  # settings is a list of (key,value) pairs
        result.update(options)
        return result

    FITTERS = []
    FIT_AVAILABLE_IDS = []
    FIT_ACTIVE_IDS = []

    def register(fitter, active=True):
        """
        Register a new fitter with bumps, if it is not already there.

        *active* is False if you don't want it showing up in the GUI selector.
        """
        # Check if already registered.
        if fitter in FITTERS:
            return

        # Check that there is no other fitter of that name
        if fitter.id in FIT_AVAILABLE_IDS:
            raise ValueError("There is already a fitter registered as %r" % fitter.id)

        # Register the fitter.
        FITTERS.append(fitter)
        FIT_AVAILABLE_IDS.append(fitter.id)

        # Make it "active" by listing it in the help menu.
        if active:
            FIT_ACTIVE_IDS.append(fitter.id)

    # Register the fitters
    register(SimplexFit)
    register(DEFit)
    register(DreamFit)
    register(BFGSFit)
    register(MPFit)
    register(PTFit, active=False)
    # register(PSFit, active=False)
    # register(RLFit, active=False)
    # register(LevenbergMarquardtFit, active=True)
    # register(SnobFit, active=False)

    FIT_DEFAULT_ID = SimplexFit.id

    assert FIT_DEFAULT_ID in FIT_ACTIVE_IDS
    assert all(f in FIT_AVAILABLE_IDS for f in FIT_ACTIVE_IDS)

    def fit(
        problem,
        method=FIT_DEFAULT_ID,
        export=None,
        resume=None,
        store=None,
        name=None,
        verbose=False,
        parallel=1,
        **options,
    ):
        """
        Simplified fit interface.

        Given a fit problem, the name of a fitter and the fitter options,
        it will run the fit and return the best value and standard error of
        the parameters.  If *verbose* is true, then the console monitor will
        be enabled, showing progress through the fit and showing the parameter
        standard error at the end of the fit, otherwise it is completely
        silent.

        Returns a scipy *OptimizeResult* object containing "x" and "dx".  Some
        fitters also include a "state" object. For dream this can be used in
        the call *bumps.dream.views.plot_all(result.state)* to generate the
        uncertainty plots. Note: success=True and status=0 for now since the
        stopping condition is not yet available from the fitters.

        If *resume=result* is provided, then attempt to resume the fit from the
        previous result.

        If *export=path* is provided, generate the standard plots and export files
        to the specified directory. This uses *name* as the basename for the output
        files, or *problem.name* if name is not provided. Name defaults to "problem".

        If *parallel=n* is provided, then run on *n* separate cpus. By default
        *parallel=1* to run on a single cpu. For slow functions set *parallel=0*
        to run on all cpus. You want to run on a single cpu if your function is
        already parallel (for example using multiprocessing or using gpu code),
        or if your function is so fast that the overhead of transfering data is
        higher than cost of *n* function calls.
        """
        from pathlib import Path
        from scipy.optimize import OptimizeResult
        from .serialize import serialize
        from .mapper import MPMapper, SerialMapper
        from .webview.server.fit_thread import ConvergenceMonitor
        from .webview.server.state_hdf5_backed import State, FitResult, ProblemState

        # verbose = True
        # Options parser stores --fit=fitter in fit_options["fit"] rather than fit_options["method"]
        if "fit" in options:
            method = options.pop("fit")
        if method not in FIT_AVAILABLE_IDS:
            raise ValueError("unknown fit method %r not one of %s" % (method, ", ".join(sorted(FIT_ACTIVE_IDS))))
        for fitclass in FITTERS:
            if fitclass.id == method:
                break

        Mapper = MPMapper if parallel != 1 else SerialMapper
        mapper = Mapper.start_mapper(problem, [], cpus=parallel)
        convergence = ConvergenceMonitor(problem)
        monitors = [convergence]
        if verbose:
            monitors.append(ConsoleMonitor(problem))
        driver = FitDriver(fitclass=fitclass, problem=problem, monitors=monitors, mapper=mapper, **options)
        driver.clip()  # make sure fit starts within domain
        # x0 = problem.getp()
        if resume is not None:
            problem.setp(resume.x)
        x, fx = driver.fit(fit_state=None if resume is None else resume.state)
        problem.setp(x)
        if verbose:
            print("final chisq", problem.chisq_str())
            driver.show_err()

        # TODO: can we put this in a function in state_hdf5_backed?
        if store is not None:
            # TODO: strip non-options such as mapper from fit options
            store = Path(store)
            state = State()
            if store.exists():
                state.read_session_file(store)
            fitting = FitResult(
                method=method, options=options, convergence=np.array(convergence.quantiles), fit_state=driver.fitter.state
            )
            try:
                serialize(problem)
                serializer = "dataclass"
            except Exception as exc:
                # import traceback; traceback.print_exc()
                if verbose:
                    print("Problem stored using cloudpickle. It may not load in newer python versions.")
                    print(f"error: {exc}")
                serializer = "cloudpickle"
            state.problem = ProblemState(fitProblem=problem, serializer=serializer)
            state.fitting = fitting
            state.save_to_history(label="fit")
            state.write_session_file(store)

        if export is not None:
            from .webview.server.api import _export_results

            _export_results(Path(export), problem, driver.fitter.state, serializer="dataclass", name=name)

        result = OptimizeResult(
            x=x,
            dx=driver.stderr(),
            fun=fx,
            # TODO: need better success/status/message handling
            success=True,
            status=0,
            message="successful termination",
            nit=driver.monitor_runner.history.step[0],  # number of iterations
            # nfev=0, # number of function evaluations
            # njev, nhev # jacobian and hessian evaluations
            # maxcv=0, # max constraint violation
        )
        # Non-standard result
        result.state = driver.fitter.state
        return result

    def test_fitters():
        """
        Run the fit tests to make sure they work.
        """
        from .curve import Curve
        from .fitproblem import FitProblem

        x = [1, 2, 3, 4, 5, 6]
        y = [2.1, 4.0, 6.3, 8.03, 9.6, 11.9]
        dy = [0.05, 0.05, 0.2, 0.05, 0.2, 0.2]

        def line(x, m, b=0):
            return m * x + b

        M = Curve(line, x, y, dy, m=2, b=2)
        M.m.range(0, 4)
        M.b.range(-5, 5)

        problem = FitProblem(M)

        # Set the tolerance for the tests (relative)
        fit_value_tol = 1e-3
        fit_error_tol = 1e-3
        expected_value = [1.106e-1, 1.970]
        expected_error = [5.799e-2, 2.055e-2]

        store = None
        export = None
        verbose = False
        parallel = 1  # Serial fit
        # TODO: test store and export as normal tests rather than one-off tests
        # store = "/tmp/teststore.h5"
        # export = "/tmp/testexport"
        # verbose = True
        # parallel = 0 # Parallel fit
        for fitter_name in FIT_ACTIVE_IDS:
            # print(f"Running {fitter_name}")
            result = fit(
                problem,
                method=fitter_name,
                verbose=verbose,
                store=store,
                export=export,
                parallel=parallel,
                name=fitter_name,
            )
            assert np.allclose(result.x, expected_value, rtol=fit_value_tol)
            if fitter_name != "dream":
                # dream error bars vary too much to test
                assert np.allclose(result.dx, expected_error, rtol=fit_error_tol)