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How can I use a vector inside an @fun?

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Hello everyone,
I want to define a function like "fun = @(x) sin(a*x)" where "a" is a vector of n dimention.
Do you have any idea?
Thank you for your support.
Greetings.

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Accepted Answer

Artemio Soto Breceda
Artemio Soto Breceda on 22 Oct 2019
I might not be understanding your question properly, but it looks like your code works just fine. Here is an example:
a = linspace(0,2*pi,1000); % Create a vector of dimension N = 1000 with values increasing
% linearly from 0 to 2*pi
fun = @(x) sin(a*x); % Define your function
plot(a, fun(1)); % plot 1 period of the sine wave (from 0 to 2*pi);
hold
plot(a, fun(2)); % x = 2
plot(a, fun(4)); % x = 4
sinewave_example.png
I made a a 1000 elements vector, then used your exact code to define fun, and used the new function with three different inputs. Works perfectly as you wrote it.

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Walter Roberson
Walter Roberson on 23 Oct 2019
I agree, in the context provided, using a vector or matrix inside an anonymous function is not a problem.
The kinds of problems that can arise:
  • the majority of the time you should use the vector operations such as .* and .^ and ./ instead of * and ^ and /
  • fzero and the minimizers such as fmincon cannot work with vectors or arrays being returned: gamultiobj is the only minimizer that can work with vectors being returned
  • integral() can only deal with vectors or arrays being returned if you use the 'arrayvalued' option
  • integral2() cannot deal with vectors or arrays being returned
  • if you are using arrayfun() or cellfun() or stuctfun() then you need to use 'uniform', 0 to return non-scalars

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More Answers (1)

Joe Vinciguerra
Joe Vinciguerra on 23 Oct 2019
Assign 'a' first, then assign 'fun'. In your application I don't believe you can do it the other way around.

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