Why my function is not vectorized

Question

JingChong Ning 2023-1-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1900250-why-my-function-is-not-vectorized

回答： Nikhilesh 2023-1-25

This is my code:

dv = [1 5 10 20 50];
vc = sqrt(0.8*200*2*365*24*3600)/1000;
figure
for i = 1:5
    dvc = dv(i);
    f = @(c) exp(-1*dvc/c)-((c/vc)^2)*(1-exp(-1*dvc/c));
    fplot(f,[10 1000])
    hold on
end

I was told by the fplot that it has array input,

Warning: Function behaves unexpectedly on array inputs. To improve performance,
properly vectorize your function to return an output with the same size and shape as
the input arguments. 
> In matlab.graphics.function.FunctionLine>getFunction
In matlab.graphics.function/FunctionLine/updateFunction
In matlab.graphics.function.FunctionLine.set.Function_I
In matlab.graphics.function.FunctionLine.set.Function
In matlab.graphics.function/FunctionLine
In fplot>singleFplot (line 245)
In fplot>@(f)singleFplot(cax,{f},limits,extraOpts,args) (line 200)
In fplot>vectorizeFplot (line 200)
In fplot (line 166)
In AE435HW2 (line 16) 

but none of the input is an array though? Does it mean my function handle c?

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Answer 1

Dyuman Joshi 2023-1-25

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1900250-why-my-function-is-not-vectorized#answer_1155850

编辑：Dyuman Joshi 2023-1-25

在 MATLAB Online 中打开

dv = [1 5 10 20 50];

vc = sqrt(0.8*200*2*365*24*3600)/1000;

figure

for i = 1:5

dvc = dv(i);

%vectorizing the function handle

f = @(c) exp(-1.*dvc./c)-((c./vc).^2).*(1-exp(-1.*dvc./c));

fplot(f,[10 1000])

hold on

end

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Answer 2

Nikhilesh 2023-1-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1900250-why-my-function-is-not-vectorized#answer_1155855

在 MATLAB Online 中打开

You can fix this issue by vectorizing the function, so that it can handle arrays of inputs and produces arrays of outputs. One way to do this is to use element-wise operations on the variables in the function, like this:

f = @(c) exp(-1*dv(i)./c)-((c/vc).^2).*(1-exp(-1*dv(i)./c));