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atomicrex
0.1
An advanced atomistic model building tool
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#include <GridCubicSpline.h>
Public Member Functions | |
| GridCubicSpline () | |
| Default constructor. | |
| void | init (int N, double delta, double derivStart=0, double derivEnd=0) |
| Initialization of the spline function. | |
| void | setKnot (int i, double y) |
| Sets the Y value of the function at a knot. | |
| int | knotCount () const |
| Returns the number of knots. | |
| double | derivStart () const |
| Returns first derivative of spline function at knot 0. | |
| double | derivEnd () const |
| Returns first derivative of spline function at the last knot. | |
| double | knotX (int i) const |
| Returns the X coordinate of the i-th knot. | |
| double | knotY (int i) const |
| Returns the Y coordinate of the i-th knot. | |
| double | knotY2 (int i) const |
| Returns the second derivative at the i-th knot. | |
| bool | parse (std::istream &stream) |
| Parses the spline knots from a file. | |
| void | prepareSpline () |
| Calculates the second derivatives of the cubic spline. | |
| double | eval (double x) const |
| Evaluates the spline function at position x. | |
| double | eval (double x, double &deriv) const |
| Evaluates the spline function and its first derivative at position x. | |
| double | cutoff () const |
| Returns the cutoff radius of this spline function. | |
| void | writeGnuplot (const FPString &filename, const FPString &title) const |
| Create a Gnuplot script that displays the spline function. | |
A one-dimensional cubic spline function.
The spline consists of N knots with coordinates (x,y).
Knots are positioned on a regular grid on the X axis, i.e., the X position of a knot is given by its index times the grid spacing. The first knot is always at X=0.
The first derivative of the function must be explicitly specified at the first and the last knot.
1.8.13