Beispiel #1
0
func TestWeightedQuadtricFit(t *testing.T) {

	var n int = 19

	data := MakeData(0.1, 2.0, 0.1)

	X := matrix.MatrixAlloc(n, 3)
	y := vector.VectorAlloc(n)
	w := vector.VectorAlloc(n)

	c := vector.VectorAlloc(3)
	cov := matrix.MatrixAlloc(3, 3)

	for i := 0; i < n; i++ {
		xi := data[i*3]
		yi := data[i*3+1]
		ei := data[i*3+2]
		fmt.Printf("%g %g +/- %g\n", xi, yi, ei)

		matrix.Set(X, i, 0, 1.0)
		matrix.Set(X, i, 1, xi)
		matrix.Set(X, i, 2, xi*xi)

		vector.Set(y, i, yi)
		vector.Set(w, i, 1.0/(ei*ei))
	}

	work := multifit.LinearAlloc(n, 3)
	_, chisq := multifit.Wlinear(X, w, y, c, cov, work)

	fmt.Printf("# best fit: Y = %g + %g X + %g X^2\n",
		vector.Get(c, 0), vector.Get(c, 1), vector.Get(c, 2))
	fmt.Printf("# covariance matrix:\n")
	fmt.Printf("[ %+.5e, %+.5e, %+.5e  \n",
		matrix.Get(cov, 0, 0), matrix.Get(cov, 0, 1), matrix.Get(cov, 0, 2))
	fmt.Printf("  %+.5e, %+.5e, %+.5e  \n",
		matrix.Get(cov, 1, 0), matrix.Get(cov, 1, 1), matrix.Get(cov, 1, 2))
	fmt.Printf("  %+.5e, %+.5e, %+.5e ]\n",
		matrix.Get(cov, 2, 0), matrix.Get(cov, 2, 1), matrix.Get(cov, 2, 2))
	fmt.Printf("# chisq = %g\n", chisq)
}
Beispiel #2
0
func (h *GslHistogram2d) Slice(xofs, xlength, yofs, ylength int) *matrix.GslMatrix {
	dim := h.Dim()
	if xlength+xofs > dim[0] ||
		ylength+yofs > dim[1] {
		gogsl.Error("histogram slice out of range", gogsl.GSL_ERANGE)
		return nil
	}
	// bin[i * ny + j]
	ptrOfs := xofs*dim[1] + yofs
	ptr := C.histogram2d_get_value_ptr((*C.gsl_histogram2d)(unsafe.Pointer(h.Ptr())), C.size_t(ptrOfs))
	dimlen := dim[0]*dim[1] - ptrOfs
	srcHdr := &reflect.SliceHeader{Data: uintptr(ptr), Len: dimlen, Cap: dimlen}
	src := *(*[]float64)(unsafe.Pointer(srcHdr))
	view := matrix.ViewArrayWithTda(src, xlength, ylength, dim[1])
	dst := matrix.MatrixAlloc(xlength, ylength)
	matrix.Memcpy(dst, view.Matrix())
	return dst
}
Beispiel #3
0
func TestEigen(t *testing.T) {

	data := []float64{1.0, 1 / 2.0, 1 / 3.0, 1 / 4.0,
		1 / 2.0, 1 / 3.0, 1 / 4.0, 1 / 5.0,
		1 / 3.0, 1 / 4.0, 1 / 5.0, 1 / 6.0,
		1 / 4.0, 1 / 5.0, 1 / 6.0, 1 / 7.0}
	m := matrix.ViewArray(data, 4, 4)
	eval := vector.VectorAlloc(4)
	evec := matrix.MatrixAlloc(4, 4)
	w := eigen.SymmvAlloc(4)
	eigen.Symmv(m.Matrix(), eval, evec, w)
	eigen.SymmvSort(eval, evec, eigen.EIGEN_SORT_ABS_ASC)
	for i := 0; i < 4; i++ {
		evalI := vector.Get(eval, i)
		evecI := matrix.Column(evec, i)
		fmt.Printf("eigenvalue = %g\n", evalI)
		fmt.Printf("eigenvector = \n")
		vector.Fprintf(os.Stdout, evecI.Vector(), "%g")
	}
}
Beispiel #4
0
func TestRobust(t *testing.T) {
	var p int = 2 // linear fit

	var a float64 = 1.45 // data slope
	var b float64 = 3.88 // data intercept

	var n int = 20

	X := matrix.MatrixAlloc(n, p)
	x := vector.VectorAlloc(n)
	y := vector.VectorAlloc(n)

	c := vector.VectorAlloc(p)
	cOls := vector.VectorAlloc(p)
	cov := matrix.MatrixAlloc(p, p)

	r := rng.RngAlloc(rng.DefaultRngType())

	// generate linear dataset
	for i := 0; i < n-3; i++ {
		dx := 10.0 / (float64(n) - 1.0)
		ei := rng.Uniform(r)
		xi := -5.0 + float64(i)*dx
		yi := a*xi + b

		vector.Set(x, i, xi)
		vector.Set(y, i, yi+ei)
	}

	// add a few outliers
	vector.Set(x, n-3, 4.7)
	vector.Set(y, n-3, -8.3)

	vector.Set(x, n-2, 3.5)
	vector.Set(y, n-2, -6.7)

	vector.Set(x, n-1, 4.1)
	vector.Set(y, n-1, -6.0)

	// construct design matrix X for linear fit
	for i := 0; i < n; i++ {
		xi := vector.Get(x, i)
		matrix.Set(X, i, 0, 1.0)
		matrix.Set(X, i, 1, xi)
	}

	// perform robust and OLS fit
	DoFit(multifit.GSL_MULTIFIT_ROBUST_OLS, X, y, cOls, cov)
	DoFit(multifit.GSL_MULTIFIT_ROBUST_BISQUARE, X, y, c, cov)

	// output data and model
	for i := 0; i < n; i++ {
		xi := vector.Get(x, i)
		yi := vector.Get(y, i)
		v := matrix.Row(X, i).Vector()
		_, yRob, _ := multifit.RobustEst(v, c, cov)
		_, yOls, _ := multifit.RobustEst(v, cOls, cov)

		fmt.Printf("%g %g %g %g\n", xi, yi, yRob, yOls)
	}

	fmt.Printf("# best fit: Y = %g + %g X\n", vector.Get(c, 0), vector.Get(c, 1))
	fmt.Printf("# covariance matrix:\n")
	fmt.Printf("# [ %+.5e, %+.5e\n", matrix.Get(cov, 0, 0), matrix.Get(cov, 0, 1))
	fmt.Printf("#   %+.5e, %+.5e\n", matrix.Get(cov, 1, 0), matrix.Get(cov, 1, 1))
}
Beispiel #5
0
func TestBspline(t *testing.T) {

	var n int = 200
	var ncoeffs int = 12
	var nbreak int = ncoeffs - 2

	rng.EnvSetup()
	r := rng.RngAlloc(rng.DefaultRngType())

	// allocate a cubic bspline workspace (k = 4)
	bw := bspline.Alloc(4, nbreak)
	B := vector.VectorAlloc(ncoeffs)

	x := vector.VectorAlloc(n)
	y := vector.VectorAlloc(n)
	X := matrix.MatrixAlloc(n, ncoeffs)
	c := vector.VectorAlloc(ncoeffs)
	w := vector.VectorAlloc(n)
	cov := matrix.MatrixAlloc(ncoeffs, ncoeffs)
	mw := multifit.LinearAlloc(n, ncoeffs)

	fmt.Printf("#m=0,S=0\n")
	// this is the data to be fitted
	for i := 0; i < n; i++ {
		xi := (15.0 / (float64(n) - 1)) * float64(i)
		yi := math.Cos(xi) * math.Exp(-0.1*xi)
		sigma := 0.1 * yi
		dy := randist.Gaussian(r, sigma)
		vector.Set(x, i, xi)
		vector.Set(y, i, yi+dy)
		vector.Set(w, i, 1.0/(sigma*sigma))
		fmt.Printf("%f %f\n", xi, yi+dy)
	}

	// use uniform breakpoints on [0, 15]
	bspline.KnotsUniform(0.0, 15.0, bw)

	// construct the fit matrix X
	for i := 0; i < n; i++ {
		xi := vector.Get(x, i)

		// compute B_j(xi) for all j
		bspline.Eval(xi, B, bw)

		// fill in row i of X
		for j := 0; j < ncoeffs; j++ {
			matrix.Set(X, i, j, vector.Get(B, j))
		}
	}

	// do the fit
	_, chisq := multifit.Wlinear(X, w, y, c, cov, mw)
	dof := float64(n - ncoeffs)
	tss := stats.Wtss(w.Data_(), w.Stride(), y.Data_(), y.Stride(), n)
	rsq := 1.0 - chisq/tss
	fmt.Printf("chisq/dof = %e, Rsq = %f\n", chisq/dof, rsq)

	fmt.Printf("#m=1,S=0\n")
	for xi := 0.0; xi < 15.0; xi += 0.1 {
		bspline.Eval(xi, B, bw)
		_, yi, _ := multifit.LinearEst(B, c, cov)
		fmt.Printf("%f %f\n", xi, yi)
	}
}