It depends entirely upon how the data is stored in the file.

For a matrix stored such that the rows are white-space delimited, and columns newline delimited, then this does the trick:

my @matrix = map[ split ], <$filehandle>;
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Though if the file/matrix is of any substantial size, then this may be preferable:

my @matrix;
push @matrix, [ split ] while <$filehandle>;
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