bug in __lin_interpn__.cc for decreasing coordinates

[John W. Eaton]

On 21-Jan-2008, Alexander Barth wrote:

| Hi all again,
| this code,
| 
| [x,y,z] = ndgrid(0:2);
| f = x.^2+y.^2+z.^2;
| fi = interpn(x,y,-z,f,1.5,1.5,-1.5)
| 
| returns NA (octave 3.0.0) while the correct answer is 7.5. The attached
| patch, handles the case for decreasing coordinate values in
| __lin_interpn__.cc
| 
| Proposed changelog:
| __lin_interpn__.cc: handle decreasing coordinate values

Sorry for the long delay, I did not intend to drop this.

I applied this patch.

Thanks,

jwe