I'll get these comparisons out now before gmp 5 comes out ;-).

Here are some comparisons with gmp for large integers. This is with the _num.scm I sent you earlier.

(define a (time (expt 3 2095903))) (define b (time (expt 7 1183294))) (define c (time (expt 11 1920505)))

I chose these numbers because they were used in a talk by Paul Zimmermann; I presume he chose them because

(map integer-length (list a b c (expt 10 1000000)))

(3321928 3321927 6643856 3321929)

I believe that on smaller numbers gmp should be significantly faster than gambit.

On my laptop (1.67GHz PowerPC 7450, gcc 4.1.2, 32 bit), times in seconds

Gambit GMP 4.2.1 (* a b) .907 .40 (quotient c a) 4.176 1.70 (integer-sqrt c) 4.179 1.35 (gcd a b) 55.494 224.31

On my desktop (2.0GHz PowerPC 970, gcc 4.1.2, 64 bit):

(* a b) .352 .13 (quotient c a) 1.744 .59 (integer-sqrt c) 1.813 .46 (gcd a b) 24.071 36.56

On a server (2.2GHz Opteron, gcc 4.1.2, 64 bit):

(* a b) .344 .17 (quotient c a) 1.550 .73 (integer-sqrt c) 1.526 .57 (gcd a b) 17.713 31.34

GMP was compiled with

gcc -O3 -mcpu=970 -m64 -o test test.c -I/pkgs/gmp-4.2.1-64/include/ - L/pkgs/gmp-4.2.1-64/lib -lgmp

and similarly for the other machines.

Brad