On Oct 23, 6:24 pm, Robert Bradshaw <[EMAIL PROTECTED]> wrote: > Is there a way to get the size of an integer (really fast, like a > macro getting the number of words)? One could perhaps override > _strassen_default_cutoff (though I don't know how much overhead this > would be for matrices with smallish entries).
There seem to be two (documented) ways to do this: 1) mpz_sizeinbase(..., 2) gives the number of bits in the number. This will be O(1), but has to count how many bits are used in the highest-order word. mpz_sizeinbase(..., 16) or mpz_sizeinbase(..., 32) may or may not be faster. 2) mpz_size(...) counts the number of words, but then you may have to care about the difference between 32-bit and 64-bit machines. (However, I could imagine that in this case just counting the size in words is the right thing... maybe the cutoff should be twice as many bits on a 64-bit processor.) Carl --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
