Function mt19937_init_by_array

numpy/random/src/mt19937/mt19937.c:42–80

* initialize by an array with array-length * init_key is the array for initializing keys * key_length is its length */

 * key_length is its length
 */
void mt19937_init_by_array(mt19937_state *state, uint32_t *init_key,
                           int key_length) {
  /* was signed in the original code. RDH 12/16/2002 */
  int i = 1;
  int j = 0;
  uint32_t *mt = state->key;
  int k;

  init_genrand(state, 19650218UL);
  k = (RK_STATE_LEN > key_length ? RK_STATE_LEN : key_length);
  for (; k; k--) {
    /* non linear */
    mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL)) +
            init_key[j] + j;
    /* for > 32 bit machines */
    mt[i] &= 0xffffffffUL;
    i++;
    j++;
    if (i >= RK_STATE_LEN) {
      mt[0] = mt[RK_STATE_LEN - 1];
      i = 1;
    }
    if (j >= key_length) {
      j = 0;
    }
  }
  for (k = RK_STATE_LEN - 1; k; k--) {
    mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) -
            i;             /* non linear */
    mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
    i++;
    if (i >= RK_STATE_LEN) {
      mt[0] = mt[RK_STATE_LEN - 1];
      i = 1;
    }
  }

  mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
}

void mt19937_gen(mt19937_state *state) {
  uint32_t y;