How to call a symbolic function from cell array

Question

Annette Ventroni 2021-5-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/841220-how-to-call-a-symbolic-function-from-cell-array

回答： Harimurali 2023-10-13

Hello, i have a problem with calling a symbolic function that is stored in cell array.

syms pp(x);

>> pp(x) = piecewise(x<0 , 0, 0<=x<=0.9 ,0.8, .9 <x<=2.7 ,0.9, 2.7<x<=4.5, 0.8, 4.5 <x<=8.1 , 0.4, 8.1 <x<=13.5 , 0.05);

>>

>> PP=cell(10,1);

>> PP{1}=pp(x);

>> pp(3)

ans =

4/5

>> PP{1}(3)

Index exceeds the number of array elements (1).

Error in sym/subsref (line 902)

R_tilde = builtin('subsref',L_tilde,Idx);

>>

Someone can help me understand how i have to call it? Thank you very much !

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Harimurali 2023-10-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/841220-how-to-call-a-symbolic-function-from-cell-array#answer_1332444

在 MATLAB Online 中打开

Hi Annette,

I understand that you want to know if there is a way to call the symbolic function stored in a cell array. In this case, calling this symbolic function from the cell array is not possible.

Alternatively, the same can be achieved by creating a MATLAB function handle for the ‘piecewise’ function and storing it in the cell array. This can be called directly by indexing the cell array. The sample MATLAB code for this is as follows:

pp = @(x, ~, ~, ~, ~, ~, ~, ~, ~, ~, ~, ~)piecewise(x < 0, 0, 0 <= x <= 0.9, 0.8, 0.9 < x <= 2.7, 0.9, 2.7 < x <= 4.5, 0.8, 4.5 < x <= 8.1, 0.4, 8.1 < x <= 13.5, 0.05); 
PP = cell(10, 1); 
PP{1} = pp; 
PP{1}(3); 

Please refer to the following documentation for more information about function handles in MATLAB:

https://in.mathworks.com/help/matlab/function-handles.html

I hope this helps.