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Manpages MathSection: User Contributed Perl Documentation (3)Updated: 2002-04-08 Index Return to Main Contents NAMEPDL::Math - extended mathematical operations and special functionsSYNOPSISuse PDL::Math; use PDL::Graphics::TriD; imag3d [SURF2D,bessj0(rvals(zeroes(50,50))/2)]; DESCRIPTIONThis 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. The functions are usually available from the system maths library, however if they are not (determined when PDL is compiled) a version from the Cephes math library is used. FUNCTIONSacosSignature: (a(); [o]b())The usual trigonometric function. Works inplace. asinSignature: (a(); [o]b())The usual trigonometric function. Works inplace. atanSignature: (a(); [o]b())The usual trigonometric function. Works inplace. coshSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. sinhSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. tanSignature: (a(); [o]b())The usual trigonometric function. Works inplace. tanhSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. ceilSignature: (a(); [o]b())Round to integral values in floating-point format. Works inplace. floorSignature: (a(); [o]b())Round to integral values in floating-point format. Works inplace. rintSignature: (a(); [o]b())Round to integral values in floating-point format. Works inplace. powSignature: (a(); b(); [o]c())Synonym for `**'. Works inplace. acoshSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. asinhSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. atanhSignature: (a(); [o]b())The standard hyperbolic function. Works inplace. erfSignature: (a(); [o]b())The error function. Works inplace. erfcSignature: (a(); [o]b())The complement of the error function. Works inplace. bessj0Signature: (a(); [o]b())The standard Bessel function. Works inplace. bessj1Signature: (a(); [o]b())The standard Bessel function. Works inplace. bessy0Signature: (a(); [o]b())The standard Bessel function. Works inplace. bessy1Signature: (a(); [o]b())The standard Bessel function. Works inplace. bessjnSignature: (a(); int n(); [o]b())The standard Bessel function. This has a second integer argument which gives the order of the function required. Works inplace. bessynSignature: (a(); int n(); [o]b())The standard Bessel function. This has a second integer argument which gives the order of the function required. Works inplace. lgammaSignature: (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. badmaskSignature: (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); isfiniteSignature: (a(); int [o]mask())Sets $mask true if $a is not a "NaN" or "inf" (either positive or negative). Works inplace. erfiSignature: (a(); [o]b())The inverse of the error function. Works inplace. ndtriSignature: (a(); [o]b())The value for which the area under the Gaussian probability density function (integrated from minus infinity) is equal to the argument (cf erfi). Works inplace. svdSignature: (a(n,m); [o]u(n,m); [o,phys]z(n); [o]v(n,n))Singular value decomposition of array.
($u, $s, $v) = svd($a); polyrootsSignature: (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, $ci); eigensSignature: ([phys]a(m); [o,phys]ev(n,n); [o,phys]e(n))Eigenvalues and -vectors of a symmetric square matrix. If passed an asymmetric matrix, the routine will warn and symmetrize it.
($e, $ev) = eigens($a); simqSignature: ([phys]a(n,n); [phys]b(n); [o,phys]x(n); int [o,phys]ips(n); int flag)Solution of simultaneous linear equations, "a x = b". $a is an "n x n" matrix (i.e., a vector of length "n*n"), stored row-wise: that is, "a(i,j) = a[ij]", where "ij = i*n + j". While this is the transpose of the normal column-wise storage, this corresponds to normal PDL usage. The contents of matrix a may be altered (but may be required for subsequent calls with flag = -1). $b, $x, $ips are vectors of length "n". Set "flag=0" to solve. Set "flag=-1" to do a new back substitution for different $b vector using the same a matrix previously reduced when "flag=0" (the $ips vector generated in the previous solution is also required). squaretotriSignature: (a(n,n); b(m))Convert a symmetric square matrix to triangular vector storage BUGSHasn't been tested on all platforms to ensure Cephes versions are picked up automatically and used correctly.AUTHORCopyright (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).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 copyright notice should be included in the file.
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