Math(3pm)						User Contributed Perl Documentation						 Math(3pm)

NAME

       PDL::Math - extended mathematical operations and special functions

SYNOPSIS

	use PDL::Math;

	use PDL::Graphics::TriD;
	imag3d [SURF2D,bessj0(rvals(zeroes(50,50))/2)];

DESCRIPTION

       This module extends PDL with more advanced mathematical functions than provided by standard Perl.

       All the functions have one input pdl, and one output, unless otherwise stated.

       Many of the functions are linked from the system maths library or the Cephes maths library (determined when PDL is compiled); a few are
       implemented entirely in PDL.

FUNCTIONS

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

       The usual trigonometric function. Works inplace.

       acos does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The usual trigonometric function. Works inplace.

       asin does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The usual trigonometric function. Works inplace.

       atan does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       cosh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       sinh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The usual trigonometric function. Works inplace.

       tan does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       tanh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       Round to integer values in floating-point format. Works inplace.

       ceil does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       Round to integer values in floating-point format. Works inplace.

       floor does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       Round to integer values in floating-point format.

       rint uses the 'round half to even' rounding method (also known as banker's rounding).  Half-integers are rounded to the nearest even
       number. This avoids a slight statistical bias inherent in always rounding half-integers up or away from zero.

       If you are looking to round half-integers up (regardless of sign), try "floor($x+0.5)".	If you want to round half-integers away from zero,
       try "floor(abs($x)+0.5)*($x<=>0)". Works inplace.

       rint does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   pow
	 Signature: (a(); b(); [o]c())

       Synonym for `**'. Works inplace.

       pow does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       acosh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       asinh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The standard hyperbolic function. Works inplace.

       atanh does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The error function. Works inplace.

       erf does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The complement of the error function. Works inplace.

       erfc does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessj0
	 Signature: (a(); [o]b())

       The regular Bessel function of the first kind, J_n Works inplace.

       bessj0 does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessj1
	 Signature: (a(); [o]b())

       The regular Bessel function of the first kind, J_n Works inplace.

       bessj1 does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessy0
	 Signature: (a(); [o]b())

       The regular Bessel function of the second kind, Y_n. Works inplace.

       bessy0 does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessy1
	 Signature: (a(); [o]b())

       The regular Bessel function of the second kind, Y_n. Works inplace.

       bessy1 does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessjn
	 Signature: (a(); int n(); [o]b())

       The regular Bessel function of the first kind, J_n .  This takes a second int argument which gives the order of the function required.
	Works inplace.

       bessjn does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   bessyn
	 Signature: (a(); int n(); [o]b())

       The regular Bessel function of the first kind, Y_n .  This takes a second int argument which gives the order of the function required.
	Works inplace.

       bessyn does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   lgamma
	 Signature: (a(); [o]b(); int[o]s())

       log gamma function

       This returns 2 piddles -- the first set gives the log(gamma) values, while the second set, of integer values, gives the sign of the gamma
       function.  This is useful for determining factorials, amongst other things.

       lgamma does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   badmask
	 Signature: (a(); b(); [o]c())

       Clears all "infs" and "nans" in $a to the corresponding value in $b.

       badmask can be run with $a inplace:

	 badmask($a->inplace,0);
	 $a->inplace->badmask(0);

       If bad values are present, these are also cleared.

   isfinite
	 Signature: (a(); int [o]mask())

       Sets $mask true if $a is not a "NaN" or "inf" (either positive or negative). Works inplace.

       Bad values are treated as "NaN" or "inf".

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

       The inverse of the error function. Works inplace.

       erfi does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

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

       The value for which the area under the Gaussian probability density function (integrated from minus infinity) is equal to the argument (cf
       erfi). Works inplace.

       ndtri does handle bad values.  It will set the bad-value flag of all output piddles if the flag is set for any of the input piddles.

   polyroots
	 Signature: (cr(n); ci(n); [o]rr(m); [o]ri(m))

       Complex roots of a complex polynomial, given coefficients in order of decreasing powers.

	($rr, $ri) = polyroots($cr, $ci);

       polyroots 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.

BUGS

       Hasn't been tested on all platforms to ensure Cephes versions are picked up automatically and used correctly.

AUTHOR

       Copyright (C) R.J.R. Williams 1997 (rjrw@ast.leeds.ac.uk), Karl Glazebrook (kgb@aaoepp.aao.gov.au) and Tuomas J. Lukka
       (Tuomas.Lukka@helsinki.fi).  Portions (C) Craig DeForest 2002 (deforest@boulder.swri.edu).

       All rights reserved. There is no warranty. You are allowed to redistribute this software / documentation under certain conditions. For
       details, see the file COPYING in the PDL distribution. If this file is separated from the PDL distribution, the PDL copyright notice should
       be included in the file.

perl v5.14.2							    2012-05-30								 Math(3pm)