Overview

This block computes the conjugate dot product (or inner product) between two vectors, the input and taps vectors. Given a set of num_points taps, the result is the sum of products between the input vector and the conjugate of the taps. The result is a single value stored in the result address and is returned as a complex float.

Dispatcher Prototype

void volk_32fc_x2_conjugate_dot_prod_32fc(lv_32fc_t* result, const lv_32fc_t* input,
const lv_32fc_t* taps, unsigned int num_points) 

Inputs

• input: vector of complex floats.
• taps: complex float taps.
• num_points: number of samples in both input and taps.

Outputs

• result: pointer to a complex float value to hold the dot product result.

Example

unsigned int N = 1000;
unsigned int alignment = volk_get_alignment();
 
lv_32fc_t* a = (lv_32fc_t*) volk_malloc(sizeof(lv_32fc_t) * N, alignment);
lv_32fc_t* b = (lv_32fc_t*) volk_malloc(sizeof(lv_32fc_t) * N, alignment);
 
for (int i = 0; i < N; ++i) {
  a[i] = lv_cmake(.50f, .50f);
  b[i] = lv_cmake(.50f, .75f);
}
 
lv_32fc_t e = (float) N * a[0] * lv_conj(b[0]); // When a and b constant
lv_32fc_t res;
 
volk_32fc_x2_conjugate_dot_prod_32fc(&res, a, b, N);
 
printf("Expected: %8.2f%+8.2fi\n", lv_real(e), lv_imag(e));
printf("Result:   %8.2f%+8.2fi\n", lv_real(res), lv_imag(res));
 
volk_free(a);
volk_free(b);