Exemplo n.º 1
0
func Solve(a sparse.Matrix, b, xInit *mat64.Vector, settings *Settings, method Method) (result Result, err error) {
	stats := Stats{
		StartTime: time.Now(),
	}

	dim, c := a.Dims()
	if dim != c {
		panic("iterative: matrix is not square")
	}
	if xInit != nil && dim != xInit.Len() {
		panic("iterative: mismatched size of the initial guess")
	}
	if b.Len() != dim {
		panic("iterative: mismatched size of the right-hand side vector")
	}

	if xInit == nil {
		xInit = mat64.NewVector(dim, nil)
	}
	if settings == nil {
		settings = DefaultSettings(dim)
	}

	ctx := Context{
		X:        mat64.NewVector(dim, nil),
		Residual: mat64.NewVector(dim, nil),
	}
	// X = xInit
	ctx.X.CopyVec(xInit)
	if mat64.Norm(ctx.X, math.Inf(1)) > 0 {
		// Residual = Ax
		sparse.MulMatVec(ctx.Residual, 1, false, a, ctx.X)
		stats.MatVecMultiplies++
	}
	// Residual = Ax - b
	ctx.Residual.SubVec(ctx.Residual, b)

	if mat64.Norm(ctx.Residual, 2) >= settings.Tolerance {
		err = iterate(method, a, b, settings, &ctx, &stats)
	}

	result = Result{
		X:       ctx.X,
		Stats:   stats,
		Runtime: time.Since(stats.StartTime),
	}
	return result, err
}
Exemplo n.º 2
0
func Solve(a sparse.Matrix, b, xInit []float64, settings *Settings, method Method) (result Result, err error) {
	stats := Stats{
		StartTime: time.Now(),
	}

	dim := len(xInit)
	if dim == 0 {
		panic("iterative: invalid dimension")
	}

	r, c := a.Dims()
	if r != c {
		panic("iterative: matrix is not square")
	}
	if c != dim {
		panic("iterative: mismatched size of the matrix")
	}
	if len(b) != dim {
		panic("iterative: mismatched size of the right-hand side vector")
	}

	if settings == nil {
		settings = DefaultSettings(dim)
	}

	ctx := Context{
		X:        make([]float64, dim),
		Residual: make([]float64, dim),
	}
	copy(ctx.X, xInit)
	copy(ctx.Residual, b)
	if floats.Norm(ctx.X, math.Inf(1)) > 0 {
		sparse.MulMatVec(-1, false, a, ctx.X, 1, 1, ctx.Residual, 1)
		stats.MatVecMultiplies++
	}

	if floats.Norm(ctx.Residual, 2) >= settings.Tolerance {
		err = iterate(method, a, b, settings, &ctx, &stats)
	}

	result = Result{
		X:       ctx.X,
		Stats:   stats,
		Runtime: time.Since(stats.StartTime),
	}
	return result, err
}