Getting an error "INDEX OUT OF BOUNDS" in my matlab program. Please help.

%%Loop for chi values for icounter=-1:1:1 chi=(icounter); end

%%Shape function for axial effect N1(chi)=(-1/2)*chi*(1-chi); N2(chi)=(1+chi)*(1-chi); N3(chi)=(1/2)*chi*(1+chi);

%%First Derivatives of Shape Function N1=diff(N1(chi),chi); N2=diff(N2(chi),chi); N3=diff(N3(chi),chi);

%%%%Second Derivatives of Shape Function N11=diff(N1(chi),chi,2); Attempted to access N1(1); index out of bounds because numel(N1)=0.(ERROR) N22=diff(N2(chi),chi,2); N33=diff(N3(chi),chi,2);

Answer 1

[KALYAN ACHARJYA]

This loop loop

for icounter=-1:1:1 
    chi=(icounter); 
end

chi=1

and When you calculate the following diff

   N1(chi)=(-1/2)*chi*(1-chi); 
    N2(chi)=(1+chi)*(1-chi);

1-chi terms lead to zero, so N1(chi) is null and you try to diff N1(chi) (Null) with respect to 1.