# How to create a syms vector

조회 수: 2(최근 30일)
Steven 2020년 5월 13일
댓글: Steven 2020년 5월 13일
How do I generate symbolic variables that I can put into a fminsearch function?
x = sym('x', [1 2]);
fun1 = 4*x(1)^2+3*x(2)+2
myfun = matlabFunction(fun1,'Vars',x);
[xout,fval,exitflag,output] = fminsearch(myfun,[1 ,2])
I tried the code above, however myfun ends up being a function of two variables x1 and x2
@(x1,x2) x2.*3.0 + x1.^2.*4.0 + 2.0
So I have to rewrite the function by hand because I don't know how to generate a symbolic function that looks like this
x(1) x(2)
So I end up rewriting the function
@(x) x(2).*3.0+x(1).^2.*4.0+2.0
and this works
myfun2 =@(x) x(2).*3.0+x(1).^2.*4.0+2.0
[xout,fval,exitflag,output] = fminsearch(myfun2,[1 ,2])
So How do I generate a symbolic vector of x that can allow me to turn fun1 into myfun2

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### 채택된 답변

Walter Roberson 2020년 5월 13일
x = sym('x', [1 2]);
fun1 = 4*x(1)^2+3*x(2)+2
myfun = matlabFunction(fun1,'Vars',{x}); %small difference from what you had
[xout,fval,exitflag,output] = fminsearch(myfun,[1 ,2])
##### 댓글 수: 1표시숨기기 없음
Steven 2020년 5월 13일
Amazing what curly braces will do, Thanks

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R2019a

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