An implementation issue with MatlabFunction
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Hello,
I have a question which I explain by an example.
function ll = LL(X1,X2,X01,X02,par1,par2,par3,par4,par5,par6)
THE BODY WILL BE EXPLAINED LATER
end
PLEASE NOTE THAT MY ACTUAL PROBLEM IS MORE COMPLICATED THAN THIS. SO, PLEASE GIVE ME GENERAL ADVICES RATHER THAN A SPECIFIC ONES WHICH PROBABLY WORK FOR THIS PROBLEM ONLY. THANKS!
This function is created by the followig commands
syms x y
syms X X0 [1 2]
syms par [1 6]
mu1(x,y)=[par(1)*x^2*y+par(2)*y^3+x^3;par(3)*x^5*y^7+par(4)*y];sigma1(x,y)=[par(5)+x*y -x;y^2*x x*y*par(6)];
V=argnames(mu1);
p=sym2cell(X0);
mu_X0=subs(mu1,V,X0).';mu_X0=mu_X0(p{:});
sigma_X0=subs(sigma1,V,X0);sigma_X0=sigma_X0(p{:});
D=sigma_X0*sigma_X0.'; det_D=simplify(det(D)); inv_D=simplify(inv(D));
dt=1;S=1/dt*(X-X0-mu_X0*dt)*inv_D*(X-X0-mu_X0*dt).';
d=2;LL=-1/2*(d*log(2*pi*dt)+log(det_D)+S);
LL=matlabFunction(LL,'File','LL','vars',[X X0 par],'Outputs',{'ll'}); %Log-Likelihood
My question: I wouldlike to make a slight change to the way this matlabfunction is created so that at the end it would look like the following
function ll = LL(X,X0,par1,par2,par3,par4,par5,par6)
BODY: here, instead of stuff like X1,X2,X01,X02 I would like to have stuff like X(1),X(2),X0(1),X0(2)
end
I find it difficult to implement this (and this is very annoying).
I look forward to your kind help!
Thanks,
Babak
采纳的回答
If you want matlabFunction to produce a vector for several arguments, in the 'Vars' argument, enclose them in square brackets to concatenate them.
Example —
syms a b x1 x2 x3
f = a*x1 + b*x2 + x3
F = matlabFunction(f, 'Vars',{a,b,[x1,x2,x3]})
.
The ‘x’ arguments will appear as a row vector of ‘in3(1)’, ‘in3(2)’ and ‘in3(3)’ however when you call the function, you can of course name the arguments anything you want. Also, the arguments in the square brackets can be any arguments you want, including all of them. They do not have to be any specific subset.
This is a general illustration, however it will work for any function you choose as a function argument to matlabFunction.
.
EDIT — Corrected typographical errors.
.
4 个评论
Mohammad Shojaei Arani
2022-12-28
Star Strider
2022-12-28
As always, my pleasure!
Walter Roberson
2022-12-28
This is the advice I gave you in https://www.mathworks.com/matlabcentral/answers/1884182-a-symbolic-implementation-issue#answer_1136137 along with an explanation for why you were having difficulty.
Mohammad Shojaei Arani
2022-12-28
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