Using the previous cumsum value of a for loop to calculate a new value

1 次查看(过去 30 天)
hi, i have a code in which in a for loop the cumulative sum of the equation needs to be used in the next loop and then put into another equation but i am having issues with matrix/array sizes.
This is my code:
A=9.41e-17;
n=5.5;
m=0.02;
B=1.054e-13;
phi=6.5;
x=4.44;
sigma=80;
%time stetup
timei=0;
timef=100;
dt=0.02;
timestep=(timef/dt)+1;
time=linspace(timei,timef,timestep);
for jj=1:timestep
if jj==0
w=0;
end
t=time(jj);
dw=B*(sigma/((1-w*(jj))^phi))*(t^m)*dt;
w=cumsum(dw);
de(jj)=(A*((sigma/((1-w))^n))*t^m*dt);
e=cumsum(de);
end
For this calculation the cumulative value of w has to be used to find the next change in w, the cumulative sum of w then has to be used to find the change in e and then the sumulative sum of e is then plotted against the time vector.
The issue i am having is when i create the vector dw by adding (jj) after it this error appears:
Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise
matrix powers, use '.^'.
Error in TEST (line 33)
de(jj)=(A*((sigma/((1-w))^n))*t^m*dt);
if i use'.^' the matrix dimensions do not agree.
Any advice is welcome, thanks
  3 个评论
DECLAN O RIORDAN
DECLAN O RIORDAN 2020-11-26
thanks for the reply,
sorry that jj should have been 1. i have now an issue of mismatched sized matrices as seen below
dpb
dpb 2020-11-26
You still don't need the if jj block in the loop; just initialize w before the loop begins.
And you reference (1-w) in the offending line, not w(jj) which is the new summation.

请先登录,再进行评论。

回答(0 个)

类别

Help CenterFile Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

产品

Community Treasure Hunt

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

Start Hunting!

Translated by