// Make copy C of A and compute C[indexes[i]] += values[i]. Indexes are in column-major order.
// Returns a new matrix.
func AddAt(A *matrix.ComplexMatrix, values []complex128, indexes []int) *matrix.ComplexMatrix {
C := A.Copy()
if len(indexes) == 0 {
return C
}
Cr := C.ComplexArray()
N := A.NumElements()
for i, k := range indexes {
if i >= len(values) {
return C
}
if k < 0 {
k = N + k
}
Cr[k] += values[i]
}
return C
}
