For Loop / Sum of Equation

Hi I am trying to figure the best way to write the sum of an equation from j=1 to j=100 and have the answers show up in the workspace. Right now in the workspace I only get Xj = 100. But I want a 1x100 matrix in the workspace. This is probable really simple but not sure how to do it

Thanks

My code:

for j = 1:100;

xj=j

end

Answer 1

[madhan ravi]

X  = zeros(1,100) %preallocation for speed

for j = 1:100 %an example

X(j) = j; %saves X in each element to avoid overwriting 

end

X

Remark : (j) inside loop is called as indexing which prevents overwriting in a loop

[madhan ravi]

if something is not clear let know

[G]

Could this work too?

syms j

Xj_sum = sum(subs(j^2, j, 1:100))

Xj_symsym = symsum(j^2, j, 1, 100);

Seems to work

[madhan ravi]

you are asking or you sorted it out?

[G]

I am asking

[madhan ravi]

Maybe you want this?

for j = 1:100 %an example
X(j) = j.^2; %saves X in each element to avoid overwriting 
end

cumsum(X)

[madhan ravi]

It’s possible try the following

syms j

for i=1:100

Xj_symsym(i) = symsum(j^2, j, 1, i);

end

Xj_symsym

Xj_symsym = double(Xj_symsym)

is this what you are looking for?