heat equation not working

This is a solution for my homework, but the code gives us an error on the next line

I appreciate your help in that that

T(i,j+1)=T(i.j)+((dt)/(dx.^2))*(T(i+1,j)-2*T(i,j)+T(i-1,j));

clc;

clear all;

for i=1:15

x(i)=i;

x1(i)=(i-1)/15;

for j=1:10

T(i,j)=0;

end

end

T(x,1)=sin(pi*x1);

dx=0.1;

dt=0.04;

for j=1:10

for i=2:15

T(i,j+1)=T(i.j)+((dt)/(dx.^2))*(T(i+1,j)-2*T(i,j)+T(i-1,j));

end

end

for i=1:15

T0(i)=T(i,1);

T1(i)=T(i,2);

T2(i)=T(i,3);

T3(i)=T(i,4);

T4(i)=T(i,5);

T5(i)=T(i,6);

end

title("Heat");

ylabel("y");

xlabel("x");

legend("HEAT EQ");

Answer 1

[Voss]

The error is because you have a typo in that line:

T(i.j)

should be:

T(i,j)

Once you correct that, you will get a new error on the same line. This error is due to trying to refer to T(i+1,j) when i is 15, i.e., T(16,j) but T has size 15 in dimension 1. To fix that, I guess the i loop should go from 2 to 14 rather than 2 to 15:

for i=2:14