in reply to Re^2: Performance problem with Clone Method
in thread Performance problem with Clone Method
Look at the get and set functions in PDL::Func.
To note, the difference between column and row operations are the difference between 0 transpose operations and 2 of them. That said, between PDL::Slices and PDL::NiceSlice there are so many ways to skin this cat I'm surprised people worry about the issue of column/row operations in PDL.
my $M = sequence(10,10);
my $row = $M->slice(':,3');
my $col = $M->slice('4,:');
my $col2 = $M->slice('5,:');
my $deep_col = $col->copy;
$col .= $col2;
$col2 .= $deep_col;
See also reorder, dice, range etc.
Update:original code example broken.
If you're doing lots of row or column manipulations, perhaps better to keep a 1d piddle of index values and manipulate those.