How to combine the functions to make the runtime shorter without anyother extra

Question

 How to combine the functions to make the runtime shorter without anyother extra elements. (need to comebine the three functions together.)  #include <stdio.h> #include <stdlib.h> #include <time.h> #include <sys/time.h> #include <string.h> #include <math.h> #include <immintrin.h> #include <x86intrin.h>  #define ALIGN __attribute__ ((aligned (32)))  double ALIGN a[1024 * 1024]; double ALIGN b[1024 * 1024]; double ALIGN c[1024 * 1024]; double ALIGN c1[1024 * 1024];   void dgemm(int n) {         int i,j,k;         for(i=0; i<n; i++)         {                 for(j=0; j<n; j++)                 {                         double cij = 0;                         for(k=0; k<n; k++)                                 cij = cij + a[i*n+k] * b[k*n+j];                         c1[i*n+j] = cij;                 }         } }  void dgemm_intrin(int n) {         int i,j,k;         for(i=0; i<n; i+=1)         {                 for(j=0; j<n; j+=4)                 {                         __m256d c4  = _mm256_load_pd(&c[i * n+j]);                         for(k=0; k<n; k++)                         {                                 __m256d a4 = _mm256_broadcast_sd(&a[i*n+k]);                                 __m256d b4 = _mm256_load_pd(&b[k*n+j]);                                 c4 = _mm256_add_pd(c4, _mm256_mul_pd(a4, b4));                         }                         _mm256_store_pd(&c[i*n+j], c4);                 }         } }   void dgemm_unrolling(int n) {         int i,j,k;         for(i=0; i<n; i++)         {                 for(j=0; j<n; j++)                 {                         double cij = 0;                         for(k=0; k<n; k+=4)                         {                                 double s1 = a[i*n+k] * b[k*n+j];                                 double s2 = a[i*n+(k+1)] * b[(k+1)*n+j];                                 double s3 = a[i*n+(k+2)] * b[(k+2)*n+j];                                 double s4 = a[i*n+(k+3)] * b[(k+3)*n+j];                                 cij += s1 + s2 + s3 + s4;                         }                         c[i*n+j] = cij;                 }         } }   #define BLOCK_SIZE 4  void do_block(int n, int si, int sj, int sk, double *a, double *b, double *c)  {   int i, j, k;   for (i=si; i<si+BLOCK_SIZE; i++)      for (j=sj; j<sj+BLOCK_SIZE; j++) {       double cij = c[i*n+j];       for (k=sk; k<sk+BLOCK_SIZE; k++)           cij += a[i*n+k] * b[k*n+j];       c[i*n+j] = cij;     } }   void dgemm_blocking(int n) {   int i, j, k;   for(i=0; i<n; i+=BLOCK_SIZE)      for(j=0; j<n; j+=BLOCK_SIZE) {        c[i*n+j] = 0;        for(k=0; k<n; k+=BLOCK_SIZE)            do_block(n, i, j, k, a, b, c);     } }  /* Implement this function with multiple optimization techniques. */ void optimized_dgemm(int n) {   dgemm_blocking(n); }  void main(int argc, char** argv) {         int i, j;         time_t t;         struct timeval start, end;         double elapsed_time;          int check_correctness = 0;         int correct = 1;          if(argc > 1)         {                 if(strcmp(argv[1], "corr") == 0)                 {                         check_correctness = 1;                 }         }          /* Initialize random number generator */         srand((unsigned) time(&t));          /* Populate the arrays with random values */         for(i=0; i<1024; i++)         {                 for(j=0; j<1024; j++)                 {                         a[i*1024+j] = (double)rand() / (RAND_MAX + 1.0);                         b[i*1024+j] = (double)rand() / (RAND_MAX + 1.0);                         c[i*1024+j] = 0.0;                         c1[i*1024+j] = 0.0;                 }         }                   gettimeofday(&start, NULL);          /* Call you optimized function optimized_dgemm */         optimized_dgemm(1024);          gettimeofday(&end, NULL);          /* For TA use only */                  if(check_correctness)         {                 dgemm(1024);                 for(i=0; (i<1024) && correct ; i++)                 {                         for(j=0; (j<1024) && correct; j++)                         {                                 if(fabs(c[i*1024+j]-c1[i*1024+j]) >= 0.0000001)                                 {                                         printf("%f != %f ", c[i*1024+j], c1[i*1024+j]);                                         correct = 0;                                 }                         }                 }                                  if(correct)                         printf("Result is correct! ");                 else                         printf("Result is incorrect! ");         }                  elapsed_time = (end.tv_sec - start.tv_sec) * 1000.0;         elapsed_time += (end.tv_usec - start.tv_usec) / 1000.0;          printf("dgemm finished in %f milliseconds. ", elapsed_time); } 

Explanation / Answer

#include #include #include #include #include #include #include #include #define ALIGN __attribute__ ((aligned (32))) double ALIGN a[1024 * 1024]; double ALIGN b[1024 * 1024]; double ALIGN c[1024 * 1024]; double ALIGN c1[1024 * 1024]; void dgemm(int n) { int i,j,k; for(i=0; i

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