// Subtract calculates A = A - B and returns A.
func (A *Matrix) SubBLAS(B *Matrix) *Matrix {
// Normal matrices.
if A.stride == A.width && B.stride == B.width {
blas.Daxpy(len(A.data), -1.0, B.data, 1, A.data, 1)
return A
}
// Submatrices.
for i := 0; i < A.height; i++ {
blas.Daxpy(A.width, -1.0, B.Row(i), 1, A.Row(i), 1)
}
return A
}
// MulSubBLAS calculates C = C - A * B.
func (C *Matrix) MulSubBLAS(A, B *Matrix) *Matrix {
for i := 0; i < A.height; i++ {
Ci := C.Row(i)
for j, aij := range A.Row(i) {
// Ci = Ci - aij * Bj
blas.Daxpy(C.width, -aij, B.Row(j), 1, Ci, 1)
}
}
return C
}
// MulBLAS calculates C = A * B.
func (C *Matrix) MulBLAS(A, B *Matrix) *Matrix {
for i := 0; i < A.height; i++ {
Ci := C.Row(i)
for k := range Ci {
Ci[k] = 0
}
for j, aij := range A.Row(i) {
// Ci += aij * Bj
blas.Daxpy(C.width, aij, B.Row(j), 1, Ci, 1)
}
}
return C
}
// Sum computes the addition of two vectors, x&y and
// puts the result in z
func Sum(n int, alpha float64, x, y, z []float64) {
if n == 3 {
z[0] = alpha*x[0] + y[0]
z[1] = alpha*x[1] + y[1]
z[2] = alpha*x[2] + y[2]
} else if n == 4 {
z[0] = alpha*x[0] + y[0]
z[1] = alpha*x[1] + y[1]
z[2] = alpha*x[2] + y[2]
z[3] = alpha*x[3] + y[3]
} else if n == 6 {
z[0] = alpha*x[0] + y[0]
z[1] = alpha*x[1] + y[1]
z[2] = alpha*x[2] + y[2]
z[3] = alpha*x[3] + y[3]
z[4] = alpha*x[4] + y[4]
z[5] = alpha*x[5] + y[5]
} else {
copy(z, y)
blas.Daxpy(n, alpha, x, 1, z, 1)
}
}
func Outer(N, m, n int, alpha float64, A, x, y []float64) {
if N != n {
panic("vec: Dimensions invalid. A.Cols() != x.Len()")
}
if alpha == 0 {
return
}
if alpha == 1 {
goto alg
}
blas.Dscal(N, alpha, x, 1)
goto alg
alg:
{
for i := 0; i < m; i++ {
blas.Daxpy(N, x[i], y, 1, A[n*i:n*i+n], 1)
}
}
}
func axpy64(alpha float64, X []float64, Y []float64) {
blas.Daxpy(len(X), alpha, X, 1, Y, 1)
}