Symbolic summation within a for-loop

2 次查看（过去 30 天）
Robert Mason
Robert Mason 2016-7-22
回答： Azzi Abdelmalek 2016-7-22
I have a function that is dependent on two variables, f(j, k). I would like to create a loop that, for each j, sums the function for each value of k. I have tried the code:
for j=1:10;
g(j)=symsum(f(j,k), k, 1, 10);
end;
However, I get an error message "Undefined function 'symsum' for input arguments of type 'double'." on running the code. What is the best way to do the above in MATLAB?

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2016-7-22
symsum cannot use the summation variable to index.
If f is not vectorized then you use
sum( arrayfun(@(k) f(j, k), 1:10) )
If f is vectorized you might be able to use
sum( f(j, 1:10) )
but you might need
sum( f(repmat(j,1,10), 1:10) )
depending on how f is coded.

更多回答（1 个）

Azzi Abdelmalek
Azzi Abdelmalek 2016-7-22
Look at this example
syms f j k
f=j*sin(k)
for jj=1:10;
ff(k)=subs(f,j,jj);
s=symsum(ff(k), k, 1, 10);
g(jj)=double(s)
end;

类别

在 Help Center 和 File Exchange 中查找有关 Calculus 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by