how to calculate the correlation coefficient of two vectors using 'symsum' function

i am trying to calculate the correlation coefficient of two vectors and put using the symsum function:

C(j,k)= N*symsum(j1(i)*j2(i),i,1,N)-symsum(j1(i),i,1,N)

where j1 and j2 are the two vectors I am getting the following error:

Error using sym/subsindex (line 1558)
Indexing input must be numeric, logical or ':'.

I hope you can help me fix this problem thanks in advance

Answer 1

[John D'Errico]

You misunderstand the purpose and use of symsum. You have vectors. They are not symbolic. They are just numbers. Just use sum instead. As for your use of i there, you cannot simply make up syntax. It looks like you are trying to create an implicit loop of some sort, and hoping that symsum can figure out what you want to do.

[RB]

@ John

Can you please have a look at this question. https://uk.mathworks.com/matlabcentral/answers/340753-error-using-sym-subsindex-line-737

Thanks.