"Matrix"
This is a simple function that returns this package name: "Math::Matrix::MaybeGSL". It allows a simple
interface as shown below for the constructors.
"isGSL"
Returns a true value is running over Math::GSL backend.
if (Matrix->isGSL) { ... }
"new"
Construct a new matrix object. Receives as arguments the number of rows and columns of the matrix being
created.
my $matrix = Matrix->new(20, 30);
Yes, although the module name is "Math::Matrix::MaybeGSL", the "Matrix" subroutine will make it easier to
use (shorter name).
"new_from_cols"
Receives a nested list with the matrix elements, one column at a time:
my $matrix = Matrix->new_from_cols( [[1, 2], [3, 4]]);
returns [ 1 3 ]
[ 2 4 ]
"new_from_rows"
Receives a nested list with the matrix elements, one row at a time:
my $matrix = Matrix->new_from_rows( [[1, 2], [3, 4]]);
returns [ 1 2 ]
[ 3 4 ]
"dim"
Returns a list (a pair) with the number of lines and columns of the matrix.
my ($rows, $columns) = $matrix->dim();
"assign"
Sets a value in a specific position. Note that indexesstartat1 unlike Perl and some other programming
languages.
# sets the first element of the matrix to 10.
$matrix->assign(1, 1, 10);
"element"
Retrieves a value from a specific position of the matrix. Note that indexesstartat1 unlike Perl and
some other programming languages.
# retrieves the second element of the first row
my $val = $matrix->element(1, 2);
"each"
Apply a specific function to every element of the matrix, returning a new one.
# square all elements
$squared_matrix = $matrix->each( { shift ** 2 } );
"hconcat"
Concatenates two matrices horizontally. Note they must have the same number of rows.
$C = $a->hconcat($b);
if A = [ 1 2 ] and B = [ 5 6 ] then C = [ 1 2 5 6 ]
[ 3 4 ] [ 7 8 ] [ 3 4 7 8 ]
"vconcat"
Concatenates two matrices horizontally. Note they must have the same number of rows.
$C = $a->vconcat($b);
if A = [ 1 2 ] and B = [ 5 6 ] then C = [ 1 2 ]
[ 3 4 ] [ 7 8 ] [ 3 4 ]
[ 5 6 ]
[ 7 8 ]
"max"
Returns the maximum value of the matrix. In scalar context the position is also returned. For vectors
(matrices whose number of rows or columns is 1) only a position value is returned.
$max = $matrix->max();
($max, $row, $col) = $matrix->max();
"min"
Returns the minimum value of the matrix. In scalar context the position is also returned. For vectors
(matrices whose number of rows or columns is 1) only a position value is returned.
$min = $matrix->min();
($min, $row, $col) = $matrix->min();
"det"
Returns the determinant of the matrix, without going through the rigamarole of computing a LR
decomposition.
"as_list"
Get the contents of a matrix instance as a Perl list.
"write"
Given a matrix and a filename, writes that matrix to the file. Note that if the file exists it will be
overwritten. Also, fileswrittenbyMath::GSLwillnotbecompatiblewithfileswrittenbyMath::MatrixReal nor vice-versa.
$matrix->write("my_matrix.dat");
"read"
Reads a matrix written by the "write" method. Note that it will only read matrices written by the same
back-end that is being used for reading.
my $matrix = Matrix->load("my_matrix.dat");
"row"
Returns the selected row in a matrix as a new matrix object. Note that indexesstartat1 unlike Perl and
some other programming languages.
my $row = $matrix->row(1);
"find_zeros"
Given a matrix, returns a nested list of indices corresponding to zero values in the given matrix. Note
that indexesstartat1 unlike Perl and some other programming languages.
my @indices = $matrix->find_zeros();
"transpose"
Returns transposed matrix.
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