Re: [SLE] fortran random number generator

On Monday 29 December 2003 10:02, Mads Martin Joergensen wrote:

* steve-ss [Dec 29. 2003 08:10]:

...

Could you please advise on the g77 fortran equivalent of the routine call gettim(ihr,imin,isec,ihth) particularly to obtain ihth. Or just anything in 9.0 that will generate a random number. Thanks and happy new year

This should do it for you. Compile with gcc -o randomnum randomnum.c. If invoked with an argument that argument is the max value of the randomnum. If no cmdline argument it will default to 2147483647.

--> begin randomnum.c <-- #include #include #include #include #include

void init_random() { unsigned int seed; FILE *devrandom;

devrandom = fopen("/dev/urandom", "r"); if(!devrandom) devrandom = fopen("/dev/random", "r");

if(!devrandom) { perror("Could not open random device"); exit(errno); }

seed = (unsigned int)fgetc(devrandom); fclose(devrandom);

srand(seed); }

int get_random(size_t maxsize) { return (int)(((float)maxsize)*rand()/((float)RAND_MAX));; }

int main(int argc, char **argv) { long maxnum = INT32_MAX;

if(argc > 1) maxnum = strtol(argv[1], (char **)NULL, 10);

init_random();

printf("%d\n", get_random(maxnum));

return 0; } --> end randomnum.c <--

Utterly amazing. Thanks to all who replied. Cheers from Steve.