I've created a new subclass of pdl's that are typically not square. I understand that pdl's are stored in column-major form in order to save memory (and speed?) in a C matrix format. Which brings me to my question: in an attempt to save memory, should I orient my pdl's such that number of columns is smaller than the number of rows, or vice versa? Computationally it does not matter, I would just need to wrap my mind around the fact that the matrices will be transposed when printed (unless I transpose them back). Perhaps an example would help. I ran a quick test in perldl which resulted in the following:

perldl> $a = zeroes 3,1000;

perldl> $b = zeroes 1000,3;

perldl> help vars
PDL variables in package main::

Name         Type   Dimension       Flow  State          Mem
----------------------------------------------------------------
$a           Double D [3,1000]             P            0.02Mb
$b           Double D [1000,3]             P            0.02Mb

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This of course would lead me to believe that it doesn't matter one way or the other. Perhaps one of you PDL experts out there could shed some light on the subject.

In reply to Which pdl orientation saves memory by dogz007

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