functions in digit2.i - i

    z0= interp2(y0,x0, z,y,x)  


  -or- z0= interp2(y0,x0, z,y,x,reg)  
return the bilinear interpolate of the function Z(X,Y) at the  
points (X0,Y0).  The X, Y, and optional REG arrays specify a  
quadrilateral mesh as for the plm function.  The Z values are  
specified at the vertices of this mesh, so Z must have the  
same dimensions as X and Y.  
Points outside the mesh get the value 0.0, unless the outside  
keyword is non-nil, in which case they get that value.  
Interpreted function, defined at i/digit2.i   line 36