Matrix interpolation with two vectors as input

I'm trying to interpolate a matrix in MATLAB with two vectors as input. I manage to do this with one value, but not with the whole vector (beta_i and x) as input. The goal is to get out the Goldensteinfactors according to the right beta_i & x values.

%% Correction factors for finite number of blade to determine % values of Ut and Ua at the blades using the Goldstein factors.

% Numbers I want to enter as input in the Goldstein factor matrix x = [0.2030 0.2915 0.3801 0.4687 0.5572 0.6458 0.7343 0.8229 0.9114 1.0000]; beta_i = [0.8182 0.7384 0.6128 0.5158 0.4404 0.3802 0.3304 0.2879 0.2491 0.1862];

% Vertical input in Godstein factor matrix: beta_ii = linspace(0, 70, 15).*pi/180; % Horizontal input in Godstein factor matrix: r_R = [0.95 linspace(0.90, 0.3, 7)];

% Goldstein factors: Xi = [[1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000, 1.000], [0.804, 0.949, 0.997, 0.999, 1.000, 1.000, 1.000, 1.000], [0.620, 0.810, 0.959, 0.993, 0.998, 0.999, 0.999, 0.997], [0.514, 0.696, 0.890, 0.966, 0.989, 0.994, 0.992, 0.983], [0.440, 0.609, 0.813, 0.921, 0.969, 0.983, 0.982, 0.964], [0.385, 0.539, 0.742, 0.868, 0.938, 0.967, 0.970, 0.946], [0.341, 0.483, 0.679, 0.814, 0.902, 0.948, 0.959, 0.933], [0.307, 0.437, 0.624, 0.763, 0.864, 0.927, 0.950, 0.926], [0.279, 0.400, 0.578, 0.717, 0.828, 0.906, 0.944, 0.927], [0.257, 0.369, 0.539, 0.678, 0.795, 0.886, 0.941, 0.935], [0.240, 0.345, 0.507, 0.644, 0.766, 0.869, 0.941, 0.951], [0.225, 0.325, 0.481, 0.617, 0.741, 0.854, 0.944, 0.973], [0.214, 0.309, 0.460, 0.594, 0.721, 0.843, 0.949, 1.000], [0.205, 0.297, 0.440, 0.576, 0.705, 0.834, 0.956, 1.033], [0.198, 0.288, 0.431, 0.562, 0.694, 0.829, 0.965, 1.068]];

% Interpolation for one value

% vq = interp1(beta_ii, Xi(:,:), 0.7, 'pchip', 1) % vv = interp1(r_R, vq(:,:),0.7, 'pchip',1)

% For the whole matrix beta_i and x

for i = 1:length(beta_i) vq(i) = interp1(beta_ii, Xi(:,i),beta_i(i), 'pchip', 1)

end vq

for j = 1:length(x) vv(j) = interp1(r_R, vq(j,:), x(j), 'pchip', 1) end vv

Answer 1

[John D'Errico]

You have a TWO dimensional array. Not a one dimensional problem, but in two dimensions.

help interp2

use the proper tool for your problem. interp1 is not that tool, while interp2 is.

[Åse Kristin Danbolt Svalastog]

I think it worked. Thanks John!

[kulgen]

I tried but it gave an error :

Error using griddedInterpolant Interpolation requires at least two sample points in each dimension.

Error in interp2>makegriddedinterp (line 228) F = griddedInterpolant(varargin{:});

Error in interp2 (line 112) F = makegriddedinterp({X,Y},V,method,extrap);

Error in GoldsteinFactors (line 39) vq = interp2(beta_ii, Xi(:,:),0.7, 'pchip', 1);