MATLAB: Combine griddedInterpolants on the same grid

griddedinterpolantMATLAB

I'm wondering if there is a way to combine griddedInterpolants on the same grid.
I have uniform ngrids (201-by-201) for x and y and three different z-grids (surfaces) 201-by-201-by-3.
To querry all three z-values for a x-y-pair I can loop through three Interpolants but is there an faster/ smarter way?
% Show plots
surf(xGrid,yGrid,zGrid(:,:,1))
surf(xGrid,yGrid,zGrid(:,:,2))
surf(xGrid,yGrid,zGrid(:,:,3))
% Interpolant for each z-surface
C(1).F = griddedInterpolant(xGrid,yGrid,zGrid(:,:,1));
C(2).F = griddedInterpolant(xGrid,yGrid,zGrid(:,:,2));
C(3).F = griddedInterpolant(xGrid,yGrid,zGrid(:,:,3));
% Querry points, eg
x = 4;
y = -1;
for i = 1 : 3
    out(i) = C(i).F(x,y);
end

Best Answer

I don't think so. If you have a large number of query points, you might try replacing the Values property of the griddedInterpolant for each of the three planes in your grid, instead of creating three different griddedInterpolant objects.
F = griddedInterpolant(xGrid,yGrid,zGrid(:,:,1));
out{1} = F(xx,yy);
F.Values = zGrid(:,:,2);
out{2} = F(xx,yy);
F.Values = zGrid(:,:,3);
out{3} = F(xx,yy);
I'm not sure if this will actually execute faster, though.
The MATLAB Math team is aware of this workflow and is considering ways to improve it.
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