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Matrix(3)	      User Contributed Perl Documentation	     Matrix(3)

NAME
       PDL::Matrix -- a	convenience matrix class for column-major access

VERSION
       This document refers to version PDL::Matrix 0.5 of PDL::Matrix

SYNOPSIS
	 use PDL::Matrix;

	 $m = mpdl [[1,2,3],[4,5,6]];
	 $m = PDL::Matrix->pdl([[1,2,3],[4,5,6]]);
	 $m = msequence(4,3);
	 @dimsa	= $a->mdims; # 'dims' is not overloaded

	 $v = vpdl [0,1,2,3]
	 $v = vzeroes(4);

DESCRIPTION
   Overview
       This package tries to help people who want to use PDL for 2D matrix
       computation with	lots of	indexing involved. It provides a PDL subclass
       so one- and two-dimensional piddles that	are used as vectors resp and
       matrices	can be typed in	using traditional matrix convention.

       If you want to know more	about matrix operation support in PDL, you
       want to read PDL::MatrixOps or PDL::Slatec.

       The original pdl	class refers to	the first index	as the first row, the
       second index as the first column	of a matrix. Consider

	 print $B = sequence(3,2)
	 [
	  [0 1 2]
	  [3 4 5]
	 ]

       which gives a 2x3 matrix	in terms of the	matrix convention, but the
       constructor used	(3,2). This might get more confusing when using	slices
       like sequence(3,2)->slice("1:2,(0)") : with traditional matrix
       convention one would expect [2 4] instead of [1 2].

       This subclass PDL::Matrix overloads the constructors and	indexing
       functions of pdls so that they are compatible with the usual matrix
       convention, where the first dimension refers to the row of a matrix. So
       now, the	above example would be written as

	 print $B = PDL::Matrix->sequence(3,2) # or $B = msequence(3,2)
	 [
	  [0 1]
	  [2 3]
	  [4 5]
	 ]

       Routines	like eigens or inv can be used without any changes.

       Furthermore one can construct and use vectors as	n x 1 matrices without
       mentioning the second index '1'.

   Implementation
       "PDL::Matrix" works by overloading a number of PDL constructors and
       methods such that first and second args (corresponding to first and
       second dims of corresponding matrices) are effectively swapped.	It is
       not yet clear if	PDL::Matrix achieves a consistent column-major look-
       and-feel	in this	way.

NOTES
       As of version 0.5 (rewrite by CED) the matrices are stored in the usual
       way, just constructed and stringified differently.  That	way indexing
       and everything else works the way you think it should.

FUNCTIONS
   mpdl, PDL::Matrix::pdl
       constructs an object of class PDL::Matrix which is a piddle child
       class.

	   $m =	mpdl [[1,2,3],[4,5,6]];
	   $m =	PDL::Matrix->pdl([[1,2,3],[4,5,6]]);

   mzeroes, mones, msequence
       constructs a PDL::Matrix	object similar to the piddle constructors
       zeroes, ones, sequence.

   vpdl
       constructs an object of class PDL::Matrix which is of matrix dimensions
       (n x 1)

	   print $v = vpdl [0,1];
	   [
	    [0]
	    [1]
	   ]

   vzeroes, vones, vsequence
       constructs a PDL::Matrix	object with matrix dimensions (n x 1),
       therefore only the first	scalar argument	is used.

	   print $v = vsequence(2);
	   [
	    [0]
	    [1]
	   ]

   kroneckerproduct
       returns kroneckerproduct	of two matrices. This is not efficiently
       implemented.

   det_general
       returns a generalized determinant of a matrix. If the matrix is not
       regular,	one can	specify	the rank of the	matrix and the corresponding
       subdeterminant is returned. This	is implemented using the "eigens"
       function.

   trace
       returns the trace of a matrix (sum of diagonals)

BUGS AND PROBLEMS
       Because we change the way piddles are constructed, not all pdl
       operators may be	applied	to piddle-matrices. The	inner product is not
       redefined. We might have	missed some functions/methods. Internal
       consistency of our approach needs yet to	be established.

       Because PDL::Matrix changes the way slicing behaves, it breaks many
       operators, notably those	in MatrixOps.

TODO
       check all PDL functions,	benchmarks, optimization, lots of other	things
       ...

AUTHOR(S)
       Stephan Heuel (stephan@heuel.org), Christian Soeller
       (c.soeller@auckland.ac.nz).

COPYRIGHT
       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.

perl v5.32.1			  2018-05-05			     Matrix(3)

NAME | VERSION | SYNOPSIS | DESCRIPTION | NOTES | FUNCTIONS | BUGS AND PROBLEMS | TODO | AUTHOR(S) | COPYRIGHT

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