Ops(3pm)

NAME
PDL::Ops - Fundamental mathematical operators

DESCRIPTION
This module provides the functions used by PDL to overload the basic mathematical operators ("+ - / *" etc.) and functions ("sin sqrt" etc.)

It also includes the function "log10", which should be a perl function so that we can overload it!

Matrix multiplication (the operator "x") is handled by the module PDL::Primitive.

SYNOPSIS
none

FUNCTIONS

  plus
  Signature: (a(); b(); [o]c(); int swap)

add two piddles

   $c = plus $x, $y, 0;     # explicit call with trailing 0
   $c = $x + $y;           # overloaded call
   $x->inplace->plus($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "+" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

plus processes bad values. The state of the bad-value flag of the output piddles is unknown.

  mult
  Signature: (a(); b(); [o]c(); int swap)

multiply two piddles

   $c = mult $x, $y, 0;     # explicit call with trailing 0
   $c = $x * $y;           # overloaded call
   $x->inplace->mult($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "*" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

mult processes bad values. The state of the bad-value flag of the output piddles is unknown.

  minus
  Signature: (a(); b(); [o]c(); int swap)

subtract two piddles

   $c = minus $x, $y, 0;     # explicit call with trailing 0
   $c = $x - $y;           # overloaded call
   $x->inplace->minus($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "-" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

minus processes bad values. The state of the bad-value flag of the output piddles is unknown.

  divide
  Signature: (a(); b(); [o]c(); int swap)

divide two piddles

   $c = divide $x, $y, 0;     # explicit call with trailing 0
   $c = $x / $y;           # overloaded call
   $x->inplace->divide($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "/" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

divide processes bad values. The state of the bad-value flag of the output piddles is unknown.

  gt
  Signature: (a(); b(); [o]c(); int swap)

the binary > (greater than) operation

   $c = gt $x, $y, 0;     # explicit call with trailing 0
   $c = $x > $y;           # overloaded call
   $x->inplace->gt($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary ">" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

gt processes bad values. The state of the bad-value flag of the output piddles is unknown.

  lt
  Signature: (a(); b(); [o]c(); int swap)

the binary < (less than) operation

   $c = lt $x, $y, 0;     # explicit call with trailing 0
   $c = $x < $y;           # overloaded call
   $x->inplace->lt($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "<" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

lt processes bad values. The state of the bad-value flag of the output piddles is unknown.

  le
  Signature: (a(); b(); [o]c(); int swap)

the binary <= (less equal) operation

   $c = le $x, $y, 0;     # explicit call with trailing 0
   $c = $x <= $y;           # overloaded call
   $x->inplace->le($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "<=" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

le processes bad values. The state of the bad-value flag of the output piddles is unknown.

  ge
  Signature: (a(); b(); [o]c(); int swap)

the binary >= (greater equal) operation

   $c = ge $x, $y, 0;     # explicit call with trailing 0
   $c = $x >= $y;           # overloaded call
   $x->inplace->ge($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary ">=" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

ge processes bad values. The state of the bad-value flag of the output piddles is unknown.

  eq
  Signature: (a(); b(); [o]c(); int swap)

binary equal to operation ("==")

   $c = eq $x, $y, 0;     # explicit call with trailing 0
   $c = $x == $y;           # overloaded call
   $x->inplace->eq($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "==" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

eq processes bad values. The state of the bad-value flag of the output piddles is unknown.

  ne
  Signature: (a(); b(); [o]c(); int swap)

binary not equal to operation ("!=")

   $c = ne $x, $y, 0;     # explicit call with trailing 0
   $c = $x != $y;           # overloaded call
   $x->inplace->ne($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "!=" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

ne processes bad values. The state of the bad-value flag of the output piddles is unknown.

  shiftleft
  Signature: (a(); b(); [o]c(); int swap)

leftshift $a by $b

   $c = shiftleft $x, $y, 0;     # explicit call with trailing 0
   $c = $x << $y;           # overloaded call
   $x->inplace->shiftleft($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "<<" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

shiftleft processes bad values. The state of the bad-value flag of the output piddles is unknown.

  shiftright
  Signature: (a(); b(); [o]c(); int swap)

rightshift $a by $b

   $c = shiftright $x, $y, 0;     # explicit call with trailing 0
   $c = $x >> $y;           # overloaded call
   $x->inplace->shiftright($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary ">>" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

shiftright processes bad values. The state of the bad-value flag of the output piddles is unknown.

  or2
  Signature: (a(); b(); [o]c(); int swap)

binary or of two piddles

   $c = or2 $x, $y, 0;     # explicit call with trailing 0
   $c = $x | $y;           # overloaded call
   $x->inplace->or2($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "|" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

or2 processes bad values. The state of the bad-value flag of the output piddles is unknown.

  and2
  Signature: (a(); b(); [o]c(); int swap)

binary and of two piddles

   $c = and2 $x, $y, 0;     # explicit call with trailing 0
   $c = $x & $y;           # overloaded call
   $x->inplace->and2($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "&" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

and2 processes bad values. The state of the bad-value flag of the output piddles is unknown.

  xor
  Signature: (a(); b(); [o]c(); int swap)

binary exclusive or of two piddles

   $c = xor $x, $y, 0;     # explicit call with trailing 0
   $c = $x ^ $y;           # overloaded call
   $x->inplace->xor($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "^" operator. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

xor processes bad values. The state of the bad-value flag of the output piddles is unknown.

  bitnot
  Signature: (a(); [o]b())

unary bit negation

   $y = ~ $x;
   $x->inplace->bitnot;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "~" operator/function.

bitnot processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  power
  Signature: (a(); b(); [o]c(); int swap)

raise piddle $a to the power $b

   $c = $x->power($y,0); # explicit function call
   $c = $a ** $b;    # overloaded use
   $x->inplace->power($y,0);     # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "**" function. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

power processes bad values. The state of the bad-value flag of the output piddles is unknown.

  atan2
  Signature: (a(); b(); [o]c(); int swap)

elementwise "atan2" of two piddles

   $c = $x->atan2($y,0); # explicit function call
   $c = atan2 $a, $b;    # overloaded use
   $x->inplace->atan2($y,0);     # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "atan2" function. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

atan2 processes bad values. The state of the bad-value flag of the output piddles is unknown.

  modulo
  Signature: (a(); b(); [o]c(); int swap)

elementwise "modulo" operation

   $c = $x->modulo($y,0); # explicit function call
   $c = $a % $b;    # overloaded use
   $x->inplace->modulo($y,0);     # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "%" function. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

modulo processes bad values. The state of the bad-value flag of the output piddles is unknown.

  spaceship
  Signature: (a(); b(); [o]c(); int swap)

elementwise "<=>" operation

   $c = $x->spaceship($y,0); # explicit function call
   $c = $a <=> $b;    # overloaded use
   $x->inplace->spaceship($y,0);     # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the binary "<=>" function. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

spaceship processes bad values. The state of the bad-value flag of the output piddles is unknown.

  sqrt
  Signature: (a(); [o]b())

elementwise square root

   $y = sqrt $x;
   $x->inplace->sqrt;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "sqrt" operator/function.

sqrt processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  abs
  Signature: (a(); [o]b())

elementwise absolute value

   $y = abs $x;
   $x->inplace->abs;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "abs" operator/function.

abs processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  sin
  Signature: (a(); [o]b())

the sin function

   $y = sin $x;
   $x->inplace->sin;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "sin" operator/function.

sin processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  cos
  Signature: (a(); [o]b())

the cos function

   $y = cos $x;
   $x->inplace->cos;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "cos" operator/function.

cos processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  not
  Signature: (a(); [o]b())

the elementwise not operation

   $y = ! $x;
   $x->inplace->not;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "!" operator/function.

not processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  exp
  Signature: (a(); [o]b())

the exponential function

   $y = exp $x;
   $x->inplace->exp;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "exp" operator/function.

exp processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  log
  Signature: (a(); [o]b())

the natural logarithm

   $y = log $x;
   $x->inplace->log;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "log" operator/function.

log processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  log10
  Signature: (a(); [o]b())

the base 10 logarithm

   $y = log10 $x;
   $x->inplace->log10;  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. This function is used to overload the unary "log10" operator/function.

log10 processes bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

  assgn
  Signature: (a(); [o]b())

Plain numerical assignment. This is used to implement the ".=" operator

If "a" is a child piddle (e.g., the result of a slice) and bad values are generated in "b", the bad value flag is set in "b", but it is NOT automatically propagated back to the parent of "a". The following idiom ensures that the badflag is propagated back to the parent of "a":

 $pdl->slice(":,(1)") .= PDL::Bad_aware_func();
 $pdl->badflag(1);
 $pdl->check_badflag();

This is unnecessary if $pdl->badflag is known to be 1 before the slice is performed.

See http://pdl.perl.org/PDLdocs/BadValues.html#dataflow_of_the_badflag for details.

  ipow
  Signature: (a(); b(); [o] ans())

raise piddle $a to integer power $b

   $c = $x->ipow($y,0);     # explicit function call
   $c = ipow $x, $y;
   $x->inplace->ipow($y,0);  # modify $x inplace

It can be made to work inplace with the "$x->inplace" syntax. Note that when calling this function explicitly you need to supply a third argument that should generally be zero (see first example). This restriction is expected to go away in future releases.

Algorithm from Wikipedia <http://en.wikipedia.org/wiki/Exponentiation_by_squaring>

ipow does not process bad values. It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

AUTHOR
Tuomas J. Lukka (lukka@fas.harvard.edu), Karl Glazebrook (kgb@aaoepp.aao.gov.au), Doug Hunt (dhunt@ucar.edu), Christian Soeller (c.soeller@auckland.ac.nz), Doug Burke (burke@ifa.hawaii.edu), and Craig DeForest (deforest@boulder.swri.edu).