> Try transposing a 4-megabyte matrix before the week is out on a machine with 32KiB of RAM and two 5-megabyte hard drives.
Transposing is just copying bytes from one place to another, isn't it? There's no maths involved, is there?
To have that run in a week with the most naive approach possible you'd only need a machine that can copy seven words a second. Are there real relevant machines that can't do that? What algorithms could help you anyway? Something to do with cache and the order in which you read and write? And you've got plenty of space as you can trivially do it in-place.
I suspect, since the poster mentioned having two hard drives, that really they're confusing transposition with inversion. These aren't the same things.
Transposing is just copying bytes from one place to another, isn't it? There's no maths involved, is there?
To have that run in a week with the most naive approach possible you'd only need a machine that can copy seven words a second. Are there real relevant machines that can't do that? What algorithms could help you anyway? Something to do with cache and the order in which you read and write? And you've got plenty of space as you can trivially do it in-place.