wxm::spline Namespace Reference

Functions
void	fpbspl (const std::vector< real > &t, const int n, const int k, const real x, const int l, std::vector< real > &h)
	Subroutine fpbspl evaluates the (k+1) non-zero b-splines of degree k at t(l) <= x < t(l+1) using the stable recurrence relation of de boor and cox.
void	eval_spline2d (const std::vector< real > &tx, const std::vector< real > &ty, const int nx, const int ny, const std::vector< real > &c, const int kx, const int ky, std::vector< real > &lx, std::vector< real > &ly, std::vector< real > &hx, std::vector< real > &hy, std::vector< std::vector< real > > &wx, std::vector< std::vector< real > > &wy, const int mx, const int my, const std::vector< real > &x, const std::vector< real > &y, std::vector< std::vector< real > > &SplineValue2D)
	Evaluate 2D B-spline values at (x, y), given the knots vector and coefficients.

Function Documentation

eval_spline2d()

void wxm::spline::eval_spline2d	(	const std::vector< real > &	tx,
		const std::vector< real > &	ty,
		const int	nx,
		const int	ny,
		const std::vector< real > &	c,
		const int	kx,
		const int	ky,
		std::vector< real > &	lx,
		std::vector< real > &	ly,
		std::vector< real > &	hx,
		std::vector< real > &	hy,
		std::vector< std::vector< real > > &	wx,
		std::vector< std::vector< real > > &	wy,
		const int	mx,
		const int	my,
		const std::vector< real > &	x,
		const std::vector< real > &	y,
		std::vector< std::vector< real > > &	SplineValue2D
	)

Evaluate 2D B-spline values at (x, y), given the knots vector and coefficients.

The algorithm is coplied from fphisp.f in FITPACK.

Parameters

tx	The vector of knot in x direction
ty	The vector of knot in y direction
c	The vector of coefficients. The size is (nx-kx-1)*(ny-kx-1) , where nx is the number of knots in x, kx is the degree of basis polynomials in x.
kx	The polynomial degree of the spline basis in x
ky	The polynomial degree of the spline basis in y
hx	Values of basis polynomial in x at one given point
hy	Values of basis polynomial in y at one given point
x	The vector of points at which to evaluate it in x
y	The vector of points at which to evalutate it in y

Returns

The 2D B-spline values at the given points

Todo:

Check data before starting computations. If the input data are invalid, control is immediately repassed to the calling program.

fpbspl()

void wxm::spline::fpbspl	(	const std::vector< real > &	t,
		const int	n,
		const int	k,
		const real	x,
		const int	l,
		std::vector< real > &	h
	)

Subroutine fpbspl evaluates the (k+1) non-zero b-splines of degree k at t(l) <= x < t(l+1) using the stable recurrence relation of de boor and cox.

Copied from fpbspl.f in FITPACK.

Parameters

t	The vector of knots
n	Integer, giving the total number of knots
k	The polynomial degree of the spline basis
x	The point at which to evaluate the (k+1) non-zero b-splines
l	The index of the knot vector where the given x is located
h	The value of the (k+1) non-zero b-splines at the given point x