Index in position 1 is invalid error

n=(L/delta_x)+1;%%lecture notes 21/1/2020. Converts rectangle to a mesh

m=(H/delta_y)+1;

x=[0:delta_x:L]';

y=[0:delta_y:H]';

A=zeros(size(y,1),size(x,1));%%setting up the A matrix

A=meshgrid(x,y);

for i=n

for j=2:m-2

pointer(i,j)=(j-1)*n+i

end

end

everytime i run the for loop it says Index in position 1 is invalid. Array indices must be positive integers or logical values. I don't understand why this is happening and how to avoid it.

Answer 1

[Fangjun Jiang]

before the loop, check the value of n and m. They might not be an integer. You are doing pointer(n,2) for the first loop.

[Maaz Madha]

I don't understand what you mean by pointer(n,2). Otherwise your advice to round my values really helped. Thanks

[Fangjun Jiang]

based on your code, the first value assigned to the matrix pointer is pointer(n,2).

You might want to double-check your for-loop code.