# Bumps 0.7.6 documentation

## bumps.util

# Source code for bumps.util

    """
    Miscellaneous utility functions.
    """
    from __future__ import division

    __all__ = ["erf", "kbhit", "profile",
               "pushdir", "push_seed", "redirect_console"]

    import sys
    import os
    try:  # CRUFT: python 2.x
        from cStringIO import StringIO
    except ImportError:
        from io import StringIO

    import numpy as np
    from numpy import ascontiguousarray as _dense
    from scipy.special import erf

    def parse_errfile(errfile):
        """
        Parse dream statistics from a particular fit.

        Returns overall chisq, list of chisq for individual models and
        a parameter dictionary with attributes for number, name, mean, median,
        p68 for 68% credible interval and p95 for 95% credible interval.

        The parameter dictionary is keyed by parameter name.

        Usually there is only one errfile in a directory, which can be
        retrieved using::

            import glob
            errfile = glob.glob(path+'/*.err')[0]
        """
        from .dream.stats import parse_var
        pars = []
        chisq = []
        overall = None
        with open(errfile) as fid:
            for line in fid:
                if line.startswith("[overall"):
                    overall = float(line.split()[1][6:-1])
                    continue

                if line.startswith("[chisq"):
                    chisq.append(float(line.split()[0][7:-1]))
                    continue

                p = parse_var(line)
                if p is not None:
                    pars.append(p)

        if overall is None:
            overall = chisq[0]
        pardict = dict((p.name, p) for p in pars)
        return overall, chisq, pardict

    def _c_erf(x):
        """
        Error function calculator.
        """
        from ._reduction import _erf
        input = _dense(x, 'd')
        output = np.empty_like(input)
        _erf(input, output)
        return output

    def _erf_test():
        assert erf(5) == 2
        assert erf(0.) == 0.
        assert (erf(np.array([0., 0.])) == 0.).all()
        assert abs(erf(3.) - 0.99997790950300136) < 1e-14

    def profile(fn, *args, **kw):
        """
        Profile a function called with the given arguments.
        """
        import cProfile
        import pstats

        result = [None]
        def call():
            result[0] = fn(*args, **kw)
        datafile = 'profile.out'
        cProfile.runctx('call()', dict(call=call), {}, datafile)
        stats = pstats.Stats(datafile)
        # order='calls'
        order = 'cumulative'
        # order='pcalls'
        # order='time'
        stats.sort_stats(order)
        stats.print_stats()
        os.unlink(datafile)
        return result[0]

    def kbhit():
        """
        Check whether a key has been pressed on the console.
        """
        try:  # Windows
            import msvcrt
            return msvcrt.kbhit()
        except ImportError:  # Unix
            import select
            i, _, _ = select.select([sys.stdin], [], [], 0.0001)
            return sys.stdin in i

    class redirect_console(object):
        """
        Console output redirection context

        The output can be redirected to a string, to an already opened file
        (anything with a *write* attribute), or to a filename which will be
        opened for the duration of the with context.  Unless *stderr* is
        specified, then both standard output and standard error are
        redirected to the same file.  The open file handle is returned on
        enter, and (if it was not an already opened file) it is closed on exit.

        If no file is specified, then output is redirected to a StringIO
        object, which has a getvalue() method which can retrieve the string.
        The StringIO object is deleted when the context ends, so be sure to
        retrieve its value within the redirect_console context.

        :Example:

        Show that output is captured in a file:

            >>> from bumps.util import redirect_console
            >>> print("hello")
            hello
            >>> with redirect_console("redirect_out.log"):
            ...     print("captured")
            >>> print("hello")
            hello
            >>> print(open("redirect_out.log").read()[:-1])
            captured
            >>> import os; os.unlink("redirect_out.log")

        Output can also be captured to a string:

            >>> with redirect_console() as fid:
            ...    print("captured to string")
            ...    captured_string = fid.getvalue()
            >>> print(captured_string.strip())
            captured to string

        """
        def __init__(self, stdout=None, stderr=None):
            self.open_files = []
            self.sys_stdout = []
            self.sys_stderr = []

            if stdout is None:
                self.open_files.append(StringIO())
                self.stdout = self.open_files[-1]
            elif hasattr(stdout, 'write'):
                self.stdout = stdout
            else:
                self.open_files.append(open(stdout, 'w'))
                self.stdout = self.open_files[-1]

            if stderr is None:
                self.stderr = self.stdout
            elif hasattr(stderr, 'write'):
                self.stderr = stderr
            else:
                self.open_files.append(open(stderr, 'w'))
                self.stderr = self.open_files[-1]

        def __del__(self):
            for f in self.open_files:
                f.close()

        def __enter__(self):
            self.sys_stdout.append(sys.stdout)
            self.sys_stderr.append(sys.stderr)
            sys.stdout = self.stdout
            sys.stderr = self.stderr
            return self.open_files[-1]

        def __exit__(self, *args):
            sys.stdout = self.sys_stdout[-1]
            sys.stderr = self.sys_stderr[-1]
            del self.sys_stdout[-1]
            del self.sys_stderr[-1]
            return False

    class pushdir(object):
        """
        Change directories for the duration of a with statement.

        :Example:

        Show that the original directory is restored::

            >>> import sys, os
            >>> original_wd = os.getcwd()
            >>> with pushdir(sys.path[0]):
            ...     pushed_wd = os.getcwd()
            ...     first_site = os.path.abspath(sys.path[0])
            ...     assert pushed_wd == first_site
            >>> restored_wd = os.getcwd()
            >>> assert original_wd == restored_wd
        """
        def __init__(self, path):
            self.path = os.path.abspath(path)

        def __enter__(self):
            self._cwd = os.getcwd()
            os.chdir(self.path)

        def __exit__(self, *args):
            os.chdir(self._cwd)

    class push_seed(object):
        """
        Set the seed value for the random number generator.

        When used in a with statement, the random number generator state is
        restored after the with statement is complete.

        :Parameters:

        *seed* : int or array_like, optional
            Seed for RandomState

        :Example:

        Seed can be used directly to set the seed::

            >>> from numpy.random import randint
            >>> push_seed(24)
            <...push_seed object at...>
            >>> print(randint(0,1000000,3))
            [242082    899 211136]

        Seed can also be used in a with statement, which sets the random
        number generator state for the enclosed computations and restores
        it to the previous state on completion::

            >>> with push_seed(24):
            ...    print(randint(0,1000000,3))
            [242082    899 211136]

        Using nested contexts, we can demonstrate that state is indeed
        restored after the block completes::

            >>> with push_seed(24):
            ...    print(randint(0,1000000))
            ...    with push_seed(24):
            ...        print(randint(0,1000000,3))
            ...    print(randint(0,1000000))
            242082
            [242082    899 211136]
            899

        The restore step is protected against exceptions in the block::

            >>> with push_seed(24):
            ...    print(randint(0,1000000))
            ...    try:
            ...        with push_seed(24):
            ...            print(randint(0,1000000,3))
            ...            raise Exception()
            ...    except Exception:
            ...        print("Exception raised")
            ...    print(randint(0,1000000))
            242082
            [242082    899 211136]
            Exception raised
            899
        """
        def __init__(self, seed=None):
            self._state = np.random.get_state()
            np.random.seed(seed)

        def __enter__(self):
            return None

        def __exit__(self, *args):
            np.random.set_state(self._state)