A concentration $A(i,j)$ varies over i,j.
I'd like to include the summation of $A(i,j)$ in my Mathematica expressions, but it evaluates the sum
In[1]: Sum[Aij, {i, imax}, {j, jmax}]
Out[1]: Aij imax jmax
i.e. Mathematica is treating all A(i,j) values as equal, so that $\sum_{j=1}^N\sum_{i=1}^M A(i,j) = NMA$. This isn't the case, how do I stop it evaluating the sum?
My system also includes terms like $\sum_{j=1}^N\sum_{i=1}^M A(i,j)u(i,j)$, which I also don't know how to write in Mathematica.
In[1]: Sum[Aij uij, {i, imax}, {j, jmax}]
Out[1]: Aij imax jmax
Aij
is the symbol Aij. Try somthing likeA[i,j]
. Also, don't use uppercase initials in symbols - might clash with a built-in... $\endgroup$ – ciao May 4 '15 at 21:05Inactive
. $\endgroup$ – Stefan R May 4 '15 at 21:32