x=2*pi*rand(100,1);%set of random x coordinates from 0 to 2pi y=2*pi*rand(100,1);%set of random y coordinates %U=exp(-(x-pi).*(x-pi)-(y-pi).*(y-pi));% gaussian U=x; [U_smooth,U_tps]=tps_coeff([x y],U,0);%calculate tps coeff xI=0:0.1:2*pi;%interpolation grid yI=0:0.1:2*pi; [XI,YI]=meshgrid(xI,yI); [npy,npx]=size(XI); XI=reshape(XI,[],1); YI=reshape(YI,[],1); EM = tps_eval([XI YI],[x y]);%evaluate interpolation on the new grid U_eval=EM*U_tps; U_eval=reshape(U_eval,npy,npx); figure(1) imagesc(U_eval,[-1 1]) [DMX,DMY] = tps_eval_dxy([XI YI],[x y]); DUX_eval=DMX*U_tps; DUY_eval=DMY*U_tps; DUX_eval=reshape(DUX_eval,npy,npx); % plot(yI,U_eval(:,5)) figure(2) DUY_eval=reshape(DUY_eval,npy,npx); imagesc(DUX_eval,[-1 1]) % plot(xI,DU_eval(:,5)) figure(3) imagesc(DUY_eval,[-1 1]) figure(4) % plot(x,U_eval(50,:),x,DUX_eval(50,:),x,DUY_eval(50,:)) size(U_eval(50,:)) size(xI) plot(xI,U_eval(50,:),xI,DUX_eval(50,:),xI,DUY_eval(50,:))