KH> I had another look at the definition of "ones" and of another routine KH> I frequently use: arange. It appears that even without rewriting them KH> in C, some speedup can be achieved: KH> KH> - in ones(), the + 1 should be done "in place", saving about 15%, more KH> if you run out of processor cache: KH> I'd also try assignment in place: KH> def ones(shape, typecode='l', savespace=0): KH> a = zeros(shape, typecode, savespace) KH> a[len(shape)*[slice(0, None)]] = 1 KH> return a This is even faster, but it is better to write "a[...] = 1", because your manual calculation of "..." gives a large overhead for small arrays. On another machine this time: Numeric.ones 10 -> 0.254ms Numeric.ones 100 -> 0.268ms Numeric.ones 1000 -> 0.340ms Numeric.ones 10000 -> 1.960ms Numeric.ones 100000 -> 29.300ms Numeric.zeros 10 -> 0.055ms Numeric.zeros 100 -> 0.059ms Numeric.zeros 1000 -> 0.068ms Numeric.zeros 10000 -> 0.430ms Numeric.zeros 100000 -> 9.800ms Add inplace 10 -> 0.246ms Add inplace 100 -> 0.255ms Add inplace 1000 -> 0.312ms Add inplace 10000 -> 1.270ms Add inplace 100000 -> 18.100ms Assign inplace 10 -> 0.192ms Assign inplace 100 -> 0.201ms Assign inplace 1000 -> 0.242ms Assign inplace 10000 -> 1.010ms Assign inplace 100000 -> 16.300ms Reshape 1 10 -> 0.842ms Reshape 1 100 -> 1.175ms Reshape 1 1000 -> 4.100ms Reshape 1 10000 -> 35.100ms Reshape 1 100000 -> 368.600ms Rob -- ===== rob@hooft.net http://www.hooft.net/people/rob/ ===== ===== R&D, Nonius BV, Delft http://www.nonius.nl/ ===== ===== PGPid 0xFA19277D ========================== Use Linux! =========