Interpolate among two independent variables with planes. More...
#include <interp2_planar.h>
Public Types  
typedef boost::numeric::ublas::vector< double >  ubvector 
typedef boost::numeric::ublas::vector< size_t >  ubvector_size_t 
Public Member Functions  
void  set_data (size_t n_points, vec_t &x, vec_t &y, vec_t &f) 
Initialize the data for the planar interpolation and compute the scaling factors.  
void  compute_scale () 
Find scaling.  
double  eval (double x, double y) const 
Perform the planar interpolation.  
double  operator() (double x, double y) const 
Perform the planar interpolation.  
template<class vec2_t >  
double  operator() (vec2_t &v) const 
Perform the planar interpolation using the first two elements of v as input.  
void  eval_points (double x, double y, double &f, size_t &i1, double &x1, double &y1, size_t &i2, double &x2, double &y2, size_t &i3, double &x3, double &y3) const 
Planar interpolation returning the closest points. More...  
Public Attributes  
double  thresh 
Threshold for colinearity (default )  
double  x_scale 
The userspecified x scale (default 1)  
double  y_scale 
The userspecified y scale (default 1)  
Protected Member Functions  
int  swap (size_t &index_1, double &dist_1, size_t &index_2, double &dist_2) const 
Swap points 1 and 2.  
Protected Attributes  
double  dx 
The scale in the x direction.  
double  dy 
The scale in the y direction.  
size_t  np 
The number of points.  
vec_t *  ux 
The xvalues.  
vec_t *  uy 
The yvalues.  
vec_t *  uf 
The fvalues.  
bool  data_set 
True if the data has been specified.  
Private Member Functions  
interp2_planar (const interp2_planar< vec_t > &)  
interp2_planar< vec_t > &  operator= (const interp2_planar< vec_t > &) 
This class performs planar interpolation when the data points are not arranged in a specified order (i.e. not on a grid). For a set of data , the value of is predicted given a new value of x and y. This interpolation is performed by finding the plane that goes through three closest points in the data set. Distances are determined with
The values and are specified in x_scale and y_scale, respectively. If these values are negative (the default) then they are computed with and .
If the x and yvalues of the entire data set lie on a line, then the interpolation will fail and the error handler will be called. Colinearity is defined by a threshold, thresh which defaults to . If the denominator,
where is an antisymmetric LeviCevita tensor, then the points are colinear. The value of thresh can be zero, but if it is negative then it will be reset to the default value for the next interpolation.
This class stores pointers to the data, not a copy. The data can be changed between interpolations without an additional call to set_data(), but the scales may need to be recomputed with compute_scale().
The vector type can be any type with a suitably defined operator
[].
The interpolation requires at least three points and set_data() will call the error handler if the first argument is less than three.
Definition at line 93 of file interp2_planar.h.

inline 
This function interpolates x
and y
into the data returning f
. It also returns the three closest x and yvalues used for computing the plane.
Definition at line 203 of file interp2_planar.h.
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