YXTOXY - Compute a regularly-sampled, monotonically increasing function x(y)
from a regularly-sampled, monotonically increasing function y(x) by
inverse linear interpolation.
yxtoxy compute a regularly sampled function x(y) from a regularly
sampled, monotonically increasing function y(x)
Function Prototype:
void yxtoxy (int nx, float dx, float fx, float y[],
int ny, float dy, float fy, float xylo, float xyhi, float x[]);
Input:
nx number of samples of y(x)
dx x sampling interval; dx>0.0 is required
fx first x
y array[nx] of y(x) values; y[0] < y[1] < ... < y[nx-1] required
ny number of samples of x(y)
dy y sampling interval; dy>0.0 is required
fy first y
xylo x value assigned to x(y) when y is less than smallest y(x)
xyhi x value assigned to x(y) when y is greater than largest y(x)
Output:
x array[ny] of x(y) values
Notes:
User must ensure that:
(1) dx>0.0 && dy>0.0
(2) y[0] < y[1] < ... < y[nx-1]
Author: Dave Hale, Colorado School of Mines, 06/02/89