getting Subscripted assignment dimension mismatch.

my codes are as follow :

when i use this , the loop works

for i=1:3
vec=(1+i):(2+i);
mat(i,:)=vec;
vec=[];
end

EDU>> mat

mat =

     2     3
     3     4
     4     5

but when i use this , it shows the error message Subscripted assignment dimension mismatch.

EDU>> for i=1:3
vec=(1+i):(3+i);
mat(i,:)=vec;
vec=[];
end
Subscripted assignment dimension mismatch.

EDU>> for i=1:5
vec=(1+i):(3+i);
mat(i,:)=vec;
vec=[];
end
Subscripted assignment dimension mismatch.

how can i rectify this ? i need this concept for a huge loop and it shows similar error message when i run my code the matrix generally runs until 5th or 6th row

HELP PLEASE !!!

[Stephen23]

Do NOT use i as the loop variable name. This is already the name of the inbuilt imaginary unit . Overriding the inbuilt variable can create difficult-to-fix errors and can be slower to resolve. Using i makes it hard to search for the variable name. Use ii or kk instead.

Answer 1

[Orion]

Hi,

if you do

for i=1:3 
    vec=(1+i):(2+i); 
    mat(i,:)=vec; 
    vec=[];
end

for i=1:3 
    vec=(1+i):(3+i); 
    mat(i,:)=vec;
    vec=[]; 
end

the you get an error.

You need to clear your workspace or define the mat variable before the loop

for i=1:3 
    vec=(1+i):(2+i); 
    mat(i,:)=vec; 
    vec=[];
end

clear mat
  for i=1:3 
      vec=(1+i):(3+i); 
      mat(i,:)=vec;
    vec=[]; 
end

The error occurs because after the first loop, mat is a matrix with 2 columns.

And in the second loop, you use a 3 element vector vec to fill the line.

so the dimensions mismatch.

Note : you should put your question in code form, so it is more readable for everyone.

[wong wei kher]

NOTED AND THANKS !!! :)