c - TinyMT example Initialisation, Usage -


i'm having problem c code when using tinymt. wanting explanation on how functions work , want wanting parameters.

my linter throwing errors :(

#include <stdio.h> #include <stdlib.h> #include "tinymt64.h"  int main(void){   int r;   tinymt64_init(r,100)   tinymt64_generate_uint64(r);   return 0; }

tinymt library being used randomly generate numbers, there no documentation on how use this, love if give me directions on how use fantastic tool!

thank in advance

let's @ comments in source code:

/**  * function initializes internal state array 64-bit  * unsigned integer seed.  * @param random tinymt state vector.  * @param seed 64-bit unsigned integer used seed.  */ void tinymt64_init(tinymt64_t * random, uint64_t seed)

the corresponding header file says:

/**  * function outputs 64-bit unsigned integer internal state.  * @param random tinymt internal status  * @return 64-bit unsigned integer r (0 <= r < 2^64)  */ inline static uint64_t tinymt64_generate_uint64(tinymt64_t * random)

the latter in header file (and inline static), because simple, , original author wanted make clear c compilers function can inlined (and "cost" of function call should avoided).

there no function random seed (an unsigned 64-bit integer), either prng generate same sequence of random numbers, or we'll need somehow generate suitable seed ourselves.

let's implement above comments example program. let's use fixed seed, 1, simplicity.

#include <stdlib.h> #include <inttypes.h> #include <stdio.h> #include "tinymt64.h"  int main(void) {     uint64_t    seed = uint64_c(1);     uint64_t    value;     tinymt64_t  prng;      tinymt64_init(&prng, seed);      value = tinymt64_generate_uint64(&prng);      printf("the first value using seed %" priu64 " %" priu64 ".\n",            seed, value);      return exit_success; }

because use gcc, saved above example.c, put 2 files in same directory, , compiled them using

gcc -wall -o2 -c tinymt64.c gcc -wall -o2 -c example.c gcc -wall -o2 example.o tinymt64.o -o example

so can run using

./example

the code standard c, , should compile on systems tinymt64 compiles, including on windows.

let's @ code.

first, tinymt64_init() takes pointer tinymt64_t, , uint64_t seed. first used state of generator, , second seed value (used initialize state). because state small structure (struct tinymt64_t, later typedef'd tinymt64_t in header file), , has no flexible array member, can declare state normal variable, tinymt64_t prng;. pointer state &prng. function returns nothing.

second, tinymt64_generate_uint64() takes pointer generator state, , returns pseudorandom number uint64_t.

finally, uint64_c() macro defined in inttypes.h (or stdint.h), , allows define unsigned 64-bit integers 0 18446744073709551615, inclusive, without guessing type suffix (none, ul, or possibly ull) might need on particular compiler. (if constant smaller 231 = 2147483648, don't need macro, having no harm.)

the priu64 macro defined in inttypes.h, , defines conversion pattern (except leading % , optional size fields) printf() family of functions needs print uint64_t properly.

if wanted read seed e.g. command line, can use e.g.

int main(int argc, char *argv[]) {     uint64_t    seed = uint64_c(1);     uint64_t    value;     tinymt64_t  prng;     char        dummy;      if (argc > 1) {         if (sscanf(argv[1], "%" scnu64 " %c", &seed, &dummy) != 1) {             fprintf(stderr, "%s: not unsigned 64-bit integer.\n", argv[1]);             return exit_failure;         }     }

which uses first command-line argument, if 1 specified, , default constant seed (1) otherwise.


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