Multiplication of Matrix , Translocation of 3D object in Perl - perl

Question

I want to multiply two matrices in Perl. 1st {n*4} with 2nd {4*n}. I want to fetch the values from a text file. my one text file looks like
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
and othe one is like the following
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
Please help me. My main motif is to multiply a 3D x,y,x coordinates with some value to translate it to other position. Thanks in advance.

Answer 1

Use Math::Matrix.
Multiplies two matrices where the length of the rows in the first matrix is the same as the length of the columns in the second matrix. Returns the product or undef in case of error.

Answer 2

PDL::Matrix can be used:
#!/usr/bin/env perl
use strict;
use warnings;
use PDL;
use PDL::Matrix;
if ( #ARGV != 2 ) {
die 'Two matrix files are required as arguments';
}
my $index = 0;
my #matrices;
while (<>) {
push #{ $matrices[$index] }, [ split /\s+/ ];
}
continue { $index++ if eof }
my $matrix_1 = PDL::Matrix->pdl( #{ $matrices[0] } );
my $matrix_2 = PDL::Matrix->pdl( #{ $matrices[1] } );
print $matrix_1 x $matrix_2;

Answer 3

The PDL module is suited for matrix computations.

Answer 4

Use PDL::Matrix and rcols
Use rcols to read in data files of whitespace separated columns. For example, using the current PDL-2.4.10 release via the pdl2 shell we demonstrate:
pdl> #cat an4.cols; # this is the [n,4] data file
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
pdl> #cat a4n.cols; # this is the [4,n] data file
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
pdl> $a = rcols 'a4n.cols', []; # read col data into 2-D piddle
Reading data into piddles of type: [ Double ]
Read in 40 elements.
pdl> $b = rcols 'an4.cols', []; # read col data into 2-D piddle
Reading data into piddles of type: [ Double ]
Read in 36 elements.
pdl> $am = PDL::Matrix->pdl($a); # covert to usual matrix dim order
pdl> $bm = PDL::Matrix->pdl($b); # covert to usual matrix dim order
pdl> p $cm = $am x $bm; # multiply the two matrices
[
[10 10 10 10 10 10 10 10 10]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0]
]
pdl> help vars # note the dim order change between $a and $am, etc
PDL variables in package main::
Name Type Dimension Flow State Mem
----------------------------------------------------------------
$a Double D [4,10] VC 0.00KB
$am Double D [10,4] VC 0.00KB PDL::Matrix
$b Double D [9,4] VC 0.00KB
$bm Double D [4,9] VC 0.00KB PDL::Matrix
$cm Double D [10,9] P 0.70KB PDL::Matrix
$Pi Double D [] P 0.01KB
Note: the only difference between $am and $a are that for the PDL::Matrix objects the dimension order convention for the 2-D matrix is reversed from the standard PDL convention. For more information on all things PDL, please go to the PDL website where you'll find links to documentation, mailing list archives, and more...