complex_mult.cpp

#include <iostream>
#include <immintrin.h>

void printVector(double* p, int count = 4)
{
    for (int i = 0; i < count; i++)
    {
        std::cout << p[i] << ' ';
    }
    std::cout << std::endl;
}

int main() {

  __m256d vec1 = _mm256_setr_pd(4.0, 5.0, 13.0, 6.0);
  __m256d vec2 = _mm256_setr_pd(9.0, 3.0, 6.0, 7.0);
  __m256d neg = _mm256_setr_pd(1.0, -1.0, 1.0, -1.0);
  
  /* Step 1: Multiply vec1 and vec2 */
  __m256d vec3 = _mm256_mul_pd(vec1, vec2);
  printVector((double*)&vec3);
  /* Step 2: Switch the real and imaginary elements of vec2 */
  vec2 = _mm256_permute_pd(vec2, 0x5);
  printVector((double*)&vec2);
  /* Step 3: Negate the imaginary elements of vec2 */
  vec2 = _mm256_mul_pd(vec2, neg);  
  
  /* Step 4: Multiply vec1 and the modified vec2 */
  __m256d vec4 = _mm256_mul_pd(vec1, vec2);

  /* Horizontally subtract the elements in vec3 and vec4 */
  vec1 = _mm256_hsub_pd(vec3, vec4);
  
  /* Display the elements of the result vector */
  double* res = (double*)&vec1;
  // printf("%lf %lf %lf %lf\n", res[0], res[1], res[2], res[3]);
  
  return 0;
}