/** Compute y <- alpha*op(a)*x + beta * y (general matrix vector multiplication) */
public static FloatMatrix gemv(
float alpha, FloatMatrix a, FloatMatrix x, float beta, FloatMatrix y) {
if (false) {
NativeBlas.sgemv(
'N', a.rows, a.columns, alpha, a.data, 0, a.rows, x.data, 0, 1, beta, y.data, 0, 1);
} else {
if (beta == 0.0f) {
for (int i = 0; i < y.length; i++) y.data[i] = 0.0f;
for (int j = 0; j < a.columns; j++) {
float xj = x.get(j);
if (xj != 0.0f) {
for (int i = 0; i < a.rows; i++) y.data[i] += a.get(i, j) * xj;
}
}
} else {
for (int j = 0; j < a.columns; j++) {
float byj = beta * y.data[j];
float xj = x.get(j);
for (int i = 0; i < a.rows; i++) y.data[j] = a.get(i, j) * xj + byj;
}
}
}
return y;
}
