/*Implements a simple Sampler, used during model inference to sample tokens.*/#ifndef SAMPLER_H#define SAMPLER_H #include <math.h> // Simple xorshift RNGunsigned int random_u32(unsigned long long *state) {    // xorshift rng: https://en.wikipedia.org/wiki/Xorshift#xorshift.2A    *state ^= *state >> 12;    *state ^= *state << 25;    *state ^= *state >> 27;    return (*state * 0x2545F4914F6CDD1Dull) >> 32;} float random_f32(unsigned long long *state) { // random float32 in [0,1)    return (random_u32(state) >> 8) / 16777216.0f;} int sample_softmax(const float* logits, int n, float coin) {    // sample index from logits (converted to probabilities using softmax)    // coin is a random number in [0, 1), usually from random_f32()    double norm = 0;    for (int i = 0; i < n; i++) {        norm += expf(logits[i]);    }    // instead of dividing all exp(logits), we can just multiply coin.    coin *= norm;    float cdf = 0.0f;    for (int i = 0; i < n; i++) {        cdf += expf(logits[i]);        if (coin < cdf) {            return i;        }    }    return n - 1; // in case of rounding errors} #endif