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