Matlab function with array input problem

Question

My question is simple but I just don't understand. I just wanted to plot Scorer function which is $$Hi(x)=\int_0^\infty{\exp(xt-\frac{t^3}{3})}dt.$$

First I tried to write, for example, x=0:0.1:1. Then I write

y = 1/(pi)*integral(@(s) exp(x*s -(s^3)/3),0,inf).

It shows error using * and inner matrix dimensions must agree.

I also tried .* and .^ but the error then becomes only, matrix dimensions must agree.

I know my question seems stupid but I am just starting to learn matlab. What is the problem and what should be the correct steps of plotting this function? Thank you!

Use elementwise arithmetic operations (.* and .^) to apply the same function to all elements of a vector at once. Without the dot, it interprets * as dot product and ^ as matrix powers. — Nick Alger, Jun 27 '17 at 21:21
Actually, I tried using the dots before * and ^ but also failed. — Zhenyuan Lu, Jun 27 '17 at 21:22
When I use .* and .^, the error becomes, matrix dimensions must agree. — Zhenyuan Lu, Jun 27 '17 at 21:26
I got confused, which is the variable? I mean the integration variable? s or x? If s, then why there is a vector for x? — Cardinal, Jun 27 '17 at 21:27
This is a function of x. So the integration variable is s. I just want to input a vector and that's the main problem. — Zhenyuan Lu, Jun 27 '17 at 21:32

score -1 · Answer 1 · edited Jun 28 '17 at 00:12

-1

You need to loop through the different x inputs.For instance, the following will do what you are looking for:

$\texttt{x=0:0.1:1;}$

$\texttt{y=zeros(size(x));}$

$\texttt{for k=1:length(x)}$

$\quad \texttt{y(k)=1/pi*integral(@(s) exp(x(k)*s-s.^3/3),0,Inf);}$

$\texttt{end}$

edited Jun 28 '17 at 00:12

dantopa

10,342

answered Jun 27 '17 at 23:01

user458389

1

Thank you very much. It solves the problem and it works! – Zhenyuan Lu Jun 28 '17 at 10:18

Matlab function with array input problem

1 Answers1