interp2Dexpl.c File Reference

Bicubic spline interpolation in explicit form. More...

#include <stdlib.h>
#include <math.h>
#include "../ascot5.h"
#include "interp.h"
#include "spline.h"

Go to the source code of this file.

Functions
int	interp2Dexpl_init_coeff (real *c, real *f, int n_x, int n_y, int bc_x, int bc_y, real x_min, real x_max, real y_min, real y_max)
	Calculate bicubic spline interpolation coefficients for scalar 2D data.
void	interp2Dexpl_init_spline (interp2D_data *str, real *c, int n_x, int n_y, int bc_x, int bc_y, real x_min, real x_max, real y_min, real y_max)
	Initialize a bicubic spline.
a5err	interp2Dexpl_eval_f (real *f, interp2D_data *str, real x, real y)
	Evaluate interpolated value of 2D scalar field.
a5err	interp2Dexpl_eval_df (real *f_df, interp2D_data *str, real x, real y)
	Evaluate interpolated value and 1st and 2nd derivatives of 2D field.

Detailed Description

Bicubic spline interpolation in explicit form.

Definition in file interp2Dexpl.c.

Function Documentation

interp2Dexpl_init_coeff()

int interp2Dexpl_init_coeff	(	real *	c,
		real *	f,
		int	n_x,
		int	n_y,
		int	bc_x,
		int	bc_y,
		real	x_min,
		real	x_max,
		real	y_min,
		real	y_max )

Calculate bicubic spline interpolation coefficients for scalar 2D data.

This function calculates the bicubic spline interpolation coefficients and stores them in a pre-allocated array. Explicit cofficients are calculated.

For each data point four coefficients are stored for spline-interpolation.

Parameters

c	allocated array of length n_y*n_x*16 to store the coefficients
f	2D data to be interpolated
n_x	number of data points in the x direction
n_y	number of data points in the y direction
bc_x	boundary condition for x axis (0) natural (1) periodic
bc_y	boundary condition for y axis (0) natural (1) periodic
x_min	minimum value of the x axis
x_max	maximum value of the x axis
y_min	minimum value of the y axis
y_max	maximum value of the y axis

Returns

zero if initialization succeeded

Definition at line 33 of file interp2Dexpl.c.

interp2Dexpl_init_spline()

void interp2Dexpl_init_spline	(	interp2D_data *	str,
		real *	c,
		int	n_x,
		int	n_y,
		int	bc_x,
		int	bc_y,
		real	x_min,
		real	x_max,
		real	y_min,
		real	y_max )

Initialize a bicubic spline.

Parameters

str	pointer to spline to be initialized
c	array where coefficients are stored
n_x	number of data points in the x direction
n_y	number of data points in the y direction
bc_x	boundary condition for x axis
bc_y	boundary condition for y axis
x_min	minimum value of the x axis
x_max	maximum value of the x axis
y_min	minimum value of the y axis
y_max	maximum value of the y axis

Definition at line 108 of file interp2Dexpl.c.

interp2Dexpl_eval_f()

a5err interp2Dexpl_eval_f	(	real *	f,
		interp2D_data *	str,
		real	x,
		real	y )

Evaluate interpolated value of 2D scalar field.

This function evaluates the interpolated value of a 2D scalar field using bicubic spline interpolation coefficients of the explicit form.

Parameters

f	variable in which to place the evaluated value
str	data struct for data interpolation
x	x-coordinate
y	y-coordinate

Returns

zero on success and one if (x,y) point is outside the domain.

Definition at line 146 of file interp2Dexpl.c.

interp2Dexpl_eval_df()

a5err interp2Dexpl_eval_df	(	real *	f_df,
		interp2D_data *	str,
		real	x,
		real	y )

Evaluate interpolated value and 1st and 2nd derivatives of 2D field.

This function evaluates the interpolated value of a 2D scalar field and its 1st and 2nd derivatives using bicubic spline interpolation coefficients of the explicit form.

The evaluated values are returned in an array with following elements:

• f_df[0] = f
• f_df[1] = f_x
• f_df[2] = f_y
• f_df[3] = f_xx
• f_df[4] = f_yy
• f_df[5] = f_xy

Parameters

f_df	array in which to place the evaluated values
str	data struct for data interpolation
x	x-coordinate
y	y-coordinate

Definition at line 220 of file interp2Dexpl.c.