MATLAB Answers


How to integral a composite function in yalmip?

Asked by Tong Liu on 13 Jul 2019
Latest activity Commented on by Tong Liu on 15 Jul 2019
sdpvar x1 x2 x3 u1
% syms x1 x2 x3 u1
hello everyone...I have define a integration by yalmip, but there are some error..
If replace by syms, there are still errors.
Could you please help me find the mistakes? THANKS.


Sign in to comment.

1 Answer

Answer by infinity
on 13 Jul 2019
 Accepted Answer

You define z as a function of x1, x2, and u1. But, you apply the integral function to compute the integral of z over the interval [0, y] and told the integral function that the variable of z is also y. It is not correct.
Let image that what you are doing like trying to compute


Thank you for your answer. As you know, z is also a function of y. Why can't I intergral according to y directly? Is that only the final variable like x and u can be used for integration?
In case, we have function z(y) = y + 3 then we can compute the integral of z with respect to y as simple by
syms y a
z = y + 3;
res = int(z,y,0,a)
where "a" is upper limit of the integral.
But, in your given code, you defined z as function of x1, x2, u1 and parameter d. Matlab can not understand that z is a function y.
Get it. Thank you for your kindly help!

Sign in to comment.