示例#1
0
文件: vector.go 项目: lessc0de/matrix
// SubVec subtracts the vector b from a, placing the result in the receiver.
func (v *Vector) SubVec(a, b *Vector) {
	ar := a.Len()
	br := b.Len()

	if ar != br {
		panic(matrix.ErrShape)
	}

	v.reuseAs(ar)

	if v.mat.Inc == 1 && a.mat.Inc == 1 && b.mat.Inc == 1 {
		// Fast path for a common case.
		asm.DaxpyUnitaryTo(v.mat.Data, -1, b.mat.Data, a.mat.Data)
		return
	}
	asm.DaxpyIncTo(v.mat.Data, uintptr(v.mat.Inc), 0,
		-1, b.mat.Data, a.mat.Data,
		uintptr(ar), uintptr(b.mat.Inc), uintptr(a.mat.Inc), 0, 0)
}
示例#2
0
文件: vector.go 项目: lessc0de/matrix
// AddScaledVec adds the vectors a and alpha*b, placing the result in the receiver.
func (v *Vector) AddScaledVec(a *Vector, alpha float64, b *Vector) {
	if alpha == 1 {
		v.AddVec(a, b)
		return
	}
	if alpha == -1 {
		v.SubVec(a, b)
		return
	}

	ar := a.Len()
	br := b.Len()

	if ar != br {
		panic(matrix.ErrShape)
	}

	v.reuseAs(ar)

	switch {
	case alpha == 0: // v <- a
		v.CopyVec(a)
	case v == a && v == b: // v <- v + alpha * v = (alpha + 1) * v
		blas64.Scal(ar, alpha+1, v.mat)
	case v == a && v != b: // v <- v + alpha * b
		if v.mat.Inc == 1 && b.mat.Inc == 1 {
			// Fast path for a common case.
			asm.DaxpyUnitaryTo(v.mat.Data, alpha, b.mat.Data, a.mat.Data)
		} else {
			asm.DaxpyInc(alpha, b.mat.Data, v.mat.Data,
				uintptr(ar), uintptr(b.mat.Inc), uintptr(v.mat.Inc), 0, 0)
		}
	default: // v <- a + alpha * b or v <- a + alpha * v
		if v.mat.Inc == 1 && a.mat.Inc == 1 && b.mat.Inc == 1 {
			// Fast path for a common case.
			asm.DaxpyUnitaryTo(v.mat.Data, alpha, b.mat.Data, a.mat.Data)
		} else {
			asm.DaxpyIncTo(v.mat.Data, uintptr(v.mat.Inc), 0,
				alpha, b.mat.Data, a.mat.Data,
				uintptr(ar), uintptr(b.mat.Inc), uintptr(a.mat.Inc), 0, 0)
		}
	}
}