6.1.3 vsip_dvouter_p - Outer Product of Two Vectors

void vsip_vouter_f(vsip_scalar_f alpha, const vsip_vview_f *x, const vsip_vview_f *y, const vsip_mview_f *r); 
void vsip_cvouter_f(vsip_cscalar_f alpha, const vsip_cvview_f *x, const vsip_cvview_f *y, const vsip_cmview_f *r);

Description

This function computes the outer product of two vectors and , scaled by , and stores the result in matrix . The outer product is defined as:

for all and , where is the -th element of vector and is the -th element of vector .

Parameters

• vsip_dscalar_p alpha: Scalar multiplier for the outer product.

• const vsip_dvview_p* x: Pointer to the first input vector of length .

• const vsip_dvview_p* y: Pointer to the second input vector of length .

• const vsip_dmview_p* r: Pointer to the output matrix of size that will store the result.

Example

vsip_vview_f *x, *y; 
vsip_mview_f *r; 
vsip_length m = 5, n = 4; 
 
// Create vectors and matrix 
x = vsip_vcreate_f(m, VSIP_MEM_NONE); 
y = vsip_vcreate_f(n, VSIP_MEM_NONE); 
r = vsip_mcreate_f(m, n, VSIP_ROW, VSIP_MEM_NONE); 
 
// Initialize vectors 
vsip_vramp_f(1.0f, 1.0f, x);  // x = [1, 2, 3, 4, 5] 
vsip_vramp_f(0.5f, 0.5f, y);  // y = [0.5, 1.0, 1.5, 2.0] 
 
// Compute outer product: r = x * y^T 
vsip_vouter_f(1.0f, x, y, r); 
 
// Print the resulting matrix 
printf("Outer product result:\n"); 
for (vsip_index i = 0; i < m; i++) { 
    for (vsip_index j = 0; j < n; j++) { 
        printf("%8.2f ", vsip_mget_f(r, i, j)); 
    } 
    printf("\n"); 
} 
 
// Compute scaled outer product: r = 2.0 * x * y^T 
vsip_vouter_f(2.0f, x, y, r); 
 
// Clean up 
vsip_valldestroy_f(x); 
vsip_valldestroy_f(y); 
vsip_malldestroy_f(r);

Notes

• The output matrix must have dimensions where is the length of vector and is the length of vector .

• The outer product is not commutative: .

• If , the result will be a zero matrix regardless of the input vectors.