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#include <u.h>
#include <libn.h>
#include <time.h>
#include <vendor/blas/cblas.h>
int
argmax2(int len, double *x)
{
int i, ix[8];
double *end;
double max[8];
max[0] = x[0]; max[1] = x[1]; max[2] = x[2]; max[3] = x[3];
max[4] = x[4]; max[5] = x[5]; max[6] = x[6]; max[7] = x[7];
for (i = 0; i < len; i+=8) {
if (x[i+0] > max[0]) {
max[0] = *x;
ix[0] = i;
}
if (x[i+1] > max[1]) {
max[1] = *x;
ix[1] = i;
}
if (x[i+2] > max[2]) {
max[2] = *x;
ix[2] = i;
}
if (x[i+3] > max[3]) {
max[3] = *x;
ix[3] = i;
}
if (x[i+4] > max[4]) {
max[4] = *x;
ix[4] = i;
}
if (x[i+5] > max[5]) {
max[5] = *x;
ix[5] = i;
}
if (x[i+6] > max[6]) {
max[6] = *x;
ix[6] = i;
}
if (x[i+7] > max[7]) {
max[7] = *x;
ix[7] = i;
}
}
for (i = 1; i < 8; i++) {
if (max[i] > max[0]) {
max[0] = max[i];
ix[0] = ix[i] + i;
}
}
return ix[0];
}
int
argmax(int len, double *x)
{
int i, ix;
double *end;
double max;
max = *x;
for (i = 0; i < len; i++) {
if (x[i] > max) {
max = *x;
ix = i;
}
}
return ix;
}
#define LEN 1000000
#define NIT 2000
error
main()
{
int i, nit;
double *x, *y, res[3];
clock_t t;
double tprof[3] = { 0 };
rng·init(0);
x = malloc(sizeof(*x)*LEN);
// y = malloc(sizeof(*x)*LEN);
#define DO_0 t = clock(); \
res[0] += argmax(LEN, x); \
t = clock() - t; \
tprof[0] += 1000.*t/CLOCKS_PER_SEC; \
#define DO_1 t = clock(); \
res[1] += argmax2(LEN, x); \
t = clock() - t; \
tprof[1] += 1000.*t/CLOCKS_PER_SEC; \
#define DO_2 t = clock(); \
res[2] += cblas_idamax(LEN, x, 1); \
t = clock() - t; \
tprof[2] += 1000.*t/CLOCKS_PER_SEC;
for (nit = 0; nit < NIT; nit++) {
for (i = 0; i < LEN; i++) {
x[i] = rng·random();
// y[i] = rng·random();
}
switch (nit % 6) {
case 0: DO_0; DO_1; DO_2; break;
case 1: DO_0; DO_2; DO_1; break;
case 2: DO_1; DO_0; DO_2; break;
case 3: DO_1; DO_2; DO_0; break;
case 4: DO_2; DO_0; DO_1; break;
case 5: DO_2; DO_1; DO_0; break;
}
}
printf("mean time/iteration (naive): %fms\n", tprof[0]/NIT);
printf("--> result (naive): %f\n", res[0]);
printf("mean time/iteration (unrolled): %fms\n", tprof[1]/NIT);
printf("--> result (unrolled): %f\n", res[1]);
printf("mean time/iteration (openblas): %fms\n", tprof[2]/NIT);
printf("--> result (openblas): %f\n", res[2]);
return 0;
}
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