Interpolating [3,3] matrix valued function using interp3

Hello everyone

I have a [3,3] matrix valued function that I would like to interpolate using interp3 if that is possible. The sampled function is given in the form of a [N,N,N,3,3] matrix similar to the code sample below:

N=25;

coords=linspace(0,1,N);

[X,Y,Z]=meshgrid(coords,coords,coords);

values=zeros(N,N,N,3,3);

for i=1:1:N

for j=1:1:N

for k=1:1:N

values(i,j,k,:,:)=rand(3,3);

end

end

end

f=@(x,y,z) interp3(X,Y,Z,values,x,y,z);

f(0.5,0.5,0.5)

I'm not quite sure how I should go about using interp3 to interpolate said function?

Answer 1

[Rishabh Singh]

Since your matrix is 5-Dimensional you will have to use "interpn", and "ndgrid".

Below code should work, and provide you the required output.

N=25;

coords=linspace(0,1,N);

[X,Y,Z]=ndgrid(coords,coords,coords);

values=zeros(N,N,N,3,3);

for i=1:1:N

for j=1:1:N

for k=1:1:

values(i,j,k,:,:) = rand(3,3);

end

end

end

f=@(x,y,z) interpn(X,Y,Z,values,x,y,z);

output = squeeze(f(0.5,0.5,0.5))

Hope this helps.