Definite integral in (embedded) Matlab function

Question

sahand 2012-11-11

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Hi

I am trying to implement an evolutionary optimization algorithm in the middle of a simulink model via (embedded) matlab function. There is a need for computing a definite integral in the algorithm. Therefore in the first step and just for understanding the issue, the following definite integral was coded in (embedded) matalb editor:

function Q = DefinitIntegral(up,lo)

%#up & lo are inputs of the block as upper and lower limits of integration

Q=quad(@myfun,lo,up);

function y = myfun(x)

y = x.^2+2*x+1;

But an error occurred:

The function 'quad' is not supported for standalone code generation. See the documentation for coder.extrinsic to learn how you can use this function in simulation.

How could it be fixed

Best regards, Sahand Radmanesh

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Answer 1

Fred Smith 2012-11-12

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In later versions the MATLAB Function block supports QUAD directly, so if you can upgrade that is your best option.

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Answer 2

Azzi Abdelmalek 2012-11-11

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If you don't need to run in real time, instead of embedded function, use Matlab function.

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sahand 2012-11-11

But it's going to be a part of real time simulation

Azzi Abdelmalek 2012-11-11

编辑：Azzi Abdelmalek 2012-11-11

You have to make your own code (trapezoidal rule for example) http://en.wikipedia.org/wiki/Trapezoidal_rule very easy to do

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Answer 3

Walter Roberson 2012-11-11

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If possible, integrate symbolically first and use the closed form formula, instead of trying to integrate in your embedded code.

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sahand 2012-11-11

I wish,but if it is not, Is there any other way?

Walter Roberson 2012-11-11

What constraints can you give as to what the function to be integrated will look like? It is not practical to numerically integrate arbitrary functions with arbitrary accuracy in any real-time digital system, but if the functions are sufficiently "well-behaved" it might be practical.

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