"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 indexes start at 1 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 indexes start at 1 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, files written by Math::GSL will not be compatible with files written by Math::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 indexes start at 1 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 indexes start at 1 unlike Perl and some other programming languages.

    my @indices = $matrix->find_zeros();

"transpose"¶

Returns transposed matrix.