function wlyinterp1
x = 0:0.7:10; 
y = sin(x); 
xi = 0:.3:10; 
yy=sin(xi);
figure(1)
subR=3;subC=2;
yi = interp1(x,y,xi);err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,1);    plot(x,y,'o',xi,yi); title(['linear (default) err=' num2str(err1)])    
yi = interp1(x,y,xi,'nearest'); err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,2);    plot(x,y,'o',xi,yi); title(['nearest err=' num2str(err1)])
yi = interp1(x,y,xi,'spline'); err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,3);    plot(x,y,'o',xi,yi); title(['spline err=' num2str(err1)])
yi = interp1(x,y,xi,'pchip'); err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,4);    plot(x,y,'o',xi,yi); title(['pchip err=' num2str(err1)])
yi = interp1(x,y,xi,'cubic'); err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,5);    plot(x,y,'o',xi,yi); title(['cubic err=' num2str(err1)])
yi = interp1(x,y,xi,'v5cubic'); err1=sum((yy(1:end-1)-yi(1:end-1)).^2); 
subplot(subR,subC,6);    plot(x,y,'o',xi,yi); title(['v5cubic err=' num2str(err1)])