AVX Intrinsics help

[tidal otter]

For some homework i need to vectorise the k-loop of this code:

    for (int i = 0; i < N; i++)
        for (int j = 0; j < N; j++)
            for (int k = 0; k < N; k++) {
                C[i][j] += A[i][k] * B[k][j];
            }

}```

to which i've produced this:

```void q1_vec_k() {

    //note:  B array is transposed during the init routine

    __m256 cV, bV, aV;
    __m128 xmm1; //vector for extracting significant 128 bits of cV vector to use SS command

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {

            cV =_mm256_setzero_ps(); //sets the value of all C vector elements to 0

            for (int k = 0; k < (N/8) * 8; k += 8) {
                
                bV = _mm256_loadu_ps(&kB[k][j]); //loads 8 values of the transposed B-Array (column order of the original array)
                aV = _mm256_loadu_ps(&A[i][k]); //loads 8 values of the A array (row order)

                cV = _mm256_fmadd_ps(aV, bV, cV); //cv += (aV * bV)
            }

            cV = _mm256_hadd_ps(cV, cV);
            cV = _mm256_hadd_ps(cV, cV);
            cV = _mm256_hadd_ps(cV, cV); //at this point 1 element of cV is the sum of 8 elements

            xmm1 = _mm256_extractf128_ps(cV, 0); //extracts the first 4 elements of cV, converting it to a 128 bit vector, allowing for use of store_ss

            _mm_store_ss(&kC[i][j], xmm1);

            for (int k = (N / 8) * 8; k < N; k++) {
                kC[i][j] += A[i][k] * B[k][j];
            }
        }
    }
}```

but this doesn't produce the same result: upwards of 20 - 70 out of what it should be, so it returns things as false, and its really stressing me out. Can anyone help?

Full code listed below:

[limpid iris]

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[tidal otter]

apologies if this is a really easy fix, im quite new to all of this and its really frustrating me as i cant figure out what im doing wrong

[tidal otter]

!resolved

!solved