kadai9-4.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>

void print(int m, int n, const float * x) {
  int i,j;
  float y;
  for(i=0;i<m;i++) {
    for(j=0;j<n;j++){
      y = x[m*i + j];
      printf("  %f", y);
    }
    printf("\n");
  }
}

void rand_init(int n, float * o) {
  int i;
  float r1, r2;
  srand(time(NULL));
  for(i=0;i<n;i++){
    r1 = rand();
    r2 = r1 / RAND_MAX - 0.5;
    o[i] = r2;
  }
}

void softmax(int n, const float * x, float * y) {
  float max = x[0];
  for(int i=1;i<n;i++) {
    if(max < x[i]) max = x[i];
  }
  float bunbo = 0;
  for(int j=0;j<n;j++){
    bunbo += exp(x[j] - max);
  }
  for(int j=0;j<n;j++) {
    y[j] = exp(x[j]- max) / bunbo;
  }
}

int main(int argc, char *argv[]) {
  int n = 0;
  if(argc > 1) n = atoi(argv[1]);
  float *y = malloc(sizeof(float) * n);
  float *result = malloc(sizeof(float) * n);
  rand_init(n, y);
  print(1, n, y);
  softmax(n, y, result);
  print(1, n, result);
  return 0;
}