How can I create an ordinary floating point function from a symbolic array

Question

John Billingham 2017-9-15

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https://ww2.mathworks.cn/matlabcentral/answers/356910-how-can-i-create-an-ordinary-floating-point-function-from-a-symbolic-array

评论： John Billingham 2017-9-16

If I have some code that generates a symbolic array, I'd like to be able to turn it into a function that takes floating point inputs.

For example, if f and x are symbolic vectors and p a symbolic variable, and f is

>> disp(f)
[ x1, x2*x3, p + x4, x5, p + x3 + x2*x5 + 1]

I want to be able to use f to generate the MATLAB function

function f = f(x,p)
f(1) = x(1); f(2) = x(2)*x(3); f(3) = x(4)+p; f(4) = x(5); f(5) = x(5)*x(2)+p+1+x(3);

or its equivalent.

I'm very unclear how to do this.

Thanks for your help.

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Answer 1

Walter Roberson 2017-9-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/356910-how-can-i-create-an-ordinary-floating-point-function-from-a-symbolic-array#answer_281757

在 MATLAB Online 中打开

syms x1 x2 x3 x4 x5 p
f = [ x1, x2*x3, p + x4, x5, p + x3 + x2*x5 + 1]
matlabFunction(f, 'vars', {[x1,x2,x3,x4,x5], p})
ans =
  function_handle with value:
    @(in1,p)[in1(:,1),in1(:,2).*in1(:,3),p+in1(:,4),in1(:,5),p+in1(:,3)+in1(:,2).*in1(:,5)+1.0]