This the simple code, please have a look
A = [1 2 3; 4 5 6; 7 8 9;];
B = symsum(A(m,m),m,1,3);
Now error is - Error using sym/subsindex (line 1558) Indexing input must be numeric, logical or ':
I know that m is the symbolic variable, not a numerical value, that's why this is the error. Can anyone help me? Thanks in advance.