You've already tried PDL's 'Sparse' module?

update: this is kind of off-the-wall, but you might also want to search cpan for RLE (run-length-encoding) - there's a bunch of image-related modules which can do rle for you.

update2: Also, see the rle() and rld() functions of pdl::slices.

In reply to Re: Memory Efficient Sparse Matrix Handling by andye
in thread Memory Efficient Sparse Matrix Handling by neversaint

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