fsolve problem with syms var

2017 12 23
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更新时间：2017 12 24
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dear all
i write cod that i want to solve it with fsolve commend
at the end, my equations just contain double parameters but in the middle of my function i must consider some symbolic parameters that i remove them after some calculations
but when i run my function i got error : FSOLVE requires all values returned by functions to be of data type double and point the line i define my symbolic variable but i mention again that my final equation doesnt contain any of those symbolic var
is there any way to my problem

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shahin hashemi
shahin hashemi 2017-12-23
编辑：shahin hashemi 2017-12-23
function F = consnt7(x)
m=1.669e-3;
jx=5.743e-14;
E=2.1e11;
O=12.5e-3;
jz=1.149e-13;
G=8e10;
L=3e-3;
g=9.81;
N=1;
T1=5;
T2=0;
T3=0;
xd = sym('xd', [1 3*N], 'real');
r(:,:,1)=[1*O;0;0;];
r(:,:,2)=[(-1/2)*O;(sqrt(3))*O/2;0];
r(:,:,3)=[(-1/2)*O;-(sqrt(3))*O/2;0];
for j=2:N+1
for i=j-1
pl(:,:,j)=L*[(cos(x(3*i-2))*(1-cos(x(3*i-1))))/x(3*i-1) (sin(x(3*i-2))*(1-cos(x(3*i-1))))/x(3*i-1) sin(x(3*i-1))/x(3*i-1)]';
Rl(:,:,j)=[cos(x(3*i-2))*cos(x(3*i-1))*cos(x(3*i))-sin(x(3*i-2))*sin(x(3*i)) -cos(x(3*i-2))*cos(x(3*i-1))*sin(x(3*i))-sin(x(3*i-2))*cos(x(3*i)) cos(x(3*i-2))*sin(x(3*i-1));sin(x(3*i-2))*cos(x(3*i-1))*cos(x(3*i))+cos(x(3*i-2))*sin(x(3*i)) -sin(x(3*i-2))*cos(x(3*i-1))*sin(x(3*i))+cos(x(3*i-2))*cos(x(3*i)) sin(x(3*i-2))*sin(x(3*i-1));-sin(x(3*i-1))*cos(x(3*i)) sin(x(3*i-1))*sin(x(3*i)) cos(x(3*i-1))];
p(:,:,2)=pl(:,:,2);
end
end
R(:,:,2)=Rl(:,:,2);
R(:,:,1)=[1 0 0;0 1 0;0 0 1];
for i=3:N+1
R(:,:,i)=R(:,:,i-1)*Rl(:,:,i);
p(:,:,i)=p(:,:,i-1)+R(:,:,i-1)*pl(:,:,i);
end
for j=2:N+1
for i=j-1
wl(:,:,j)=[-sin(x(3*i-2))*xd(3*i-1)+cos(x(3*i-2))*sin(x(3*i-1))*xd(3*i);cos(x(3*i-2))*xd(3*i-1)+sin(x(3*i-2))*sin(x(3*i-1))*xd(3*i);xd(3*i-2)+cos(x(3*i-1))*xd(3*i)];
w(:,:,2)=wl(:,:,2);
end
end
for i=3:N+1
w(:,:,i)= w(:,:,i-1)+R(:,:,i-1)*wl(:,:,i);
end
for i=2:N+1
wc(:,:,i)=collect(w(:,:,i),[xd(1),xd(2),xd(3)]);%,xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);% ,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
end
for i=2:N+1
for j=1:size(w(:,:,i),1)
[wtemp,vtemp]=coeffs(wc(j,:,i),[xd(1),xd(2),xd(3)]);%,xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);%,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
[~,idx]=ismember(vtemp,[xd(1),xd(2),xd(3)]);%,xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);%,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
wk(j,idx,i)=wtemp;
end
end
for j=2:N+1
for i=j-1
pd(:,:,j)=L*[(-sin(x(3*i-2))*((1-cos(x(3*i-1)))/x(3*i-1))*xd(3*i-2))+(cos(x(3*i-2))*((sin(x(3*i-1))*x(3*i-1))-(1-cos(x(3*i-1)))/(x(3*i-1)^2))*xd(3*i-1));(cos(x(3*i-2))*((1-cos(x(3*i-1)))/x(3*i-1))*xd(3*i-2))+(sin(x(3*i-2))*((sin(x(3*i-1))*x(3*i-1))-(1-cos(x(3*i-1)))/(x(3*i-1)^2))*xd(3*i-1));(((cos(x(3*i-1))*x(3*i-1))-sin(x(3*i-1)))/(x(3*i-1)^2))*xd(3*i-1)];
v(:,:,2)=pd(:,:,2);
end
end
for i=3:N+1
v(:,:,i)=v(:,:,i-1)+cross(w(:,:,i-1),R(:,:,i-1)*pl(:,:,i))+R(:,:,i-1)*pd(:,:,i);
end
for i=2:N+1
vc(:,:,i)=collect(v(:,:,i),[xd(1),xd(2),xd(3)]);%),xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);%,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
end
for i=2:N+1
for j=1:size(v(:,:,i),1)
[vwtemp,vvtemp]=coeffs(vc(j,:,i),[xd(1),xd(2),xd(3)]);%),xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);%,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
[~,idx]=ismember(vvtemp,[xd(1),xd(2),xd(3)]);%,xd(4),xd(5),xd(6),xd(7),xd(8),xd(9),xd(10),xd(11),xd(12)]);%,xd(13),xd(14),xd(15),xd(16),xd(17),xd(18),xd(19),xd(20),xd(21),xd(22),xd(23),xd(24)]);
vk(j,idx,i)=vwtemp;
end
vk(:,3*(i-1),i)=[0;0;0];
end
for j=N+1
for i=j-1
Mb(:,:,j)=E*jx*((x(3*i-1))/L)*R(:,:,j-1)*[-sin(x(3*i-2));cos(x(3*i-2));0];
Mt(:,:,j)=-G*jz*(x(3*i-2)+x(3*i))*R(:,1,i)/L;
Me(:,:,j)=Mt(:,:,i)-Mb(:,:,i);
end
end
for j=2:N
for i=j-1
Mb(:,:,j)=E*jx*((x(3*i-1))/L)*R(:,:,j-1)*[-sin(x(3*i-2));cos(x(3*i-2));0];
end
end
for j=2:N
for i=j-1
Mt(:,:,j)=-G*jz*(x(3*i-2)+x(3*i))*R(:,3,j)/L;
end
end
for j=2:N
for i=j
Mtt(:,:,j)=G*jz*(x(3*i-2)+x(3*i))*R(:,3,j)/L;
end
end
for j=N+1
Mtt(:,:,j)=[0;0;0];
end
for i=2:N+1
MT(:,:,i)=Mt(:,:,i)+Mtt(:,:,i);
end
for i=2:N
Me(:,:,i)=Mb(:,:,i+1)-Mb(:,:,i)+MT(:,:,i);
end
for i=2:N+1 Fg(:,:,i)=-m*g*[1;0;0];
end
for i=2
ph(:,1,i)=[pl(:,:,i)+R(:,:,i)*r(:,:,1)-r(:,:,1)];
ph(:,2,i)=[pl(:,:,i)+R(:,:,i)*r(:,:,2)-r(:,:,2)];
ph(:,3,i)=[pl(:,:,i)+R(:,:,i)*r(:,:,3)-r(:,:,3)];
end
for i=3:N+1
ph(:,1,i)=[R(:,:,i-1)*pl(:,:,i)+R(:,:,i)*r(:,:,1)-R(:,:,i-1)*r(:,:,1)];
ph(:,2,i)=[R(:,:,i-1)*pl(:,:,i)+R(:,:,i)*r(:,:,2)-R(:,:,i-1)*r(:,:,2)];
ph(:,3,i)=[R(:,:,i-1)*pl(:,:,i)+R(:,:,i)*r(:,:,3)-R(:,:,i-1)*r(:,:,3)];
end
for i=2:N+1
ap(:,:,i)=[sqrt(ph(1,1,i)^2+ph(2,1,i)^2+ph(3,1,i)^2);sqrt(ph(1,2,i)^2+ph(2,2,i)^2+ph(3,2,i)^2);sqrt(ph(1,3,i)^2+ph(2,3,i)^2+ph(3,3,i)^2)];
f(:,:,i)=[ph(:,1,i)/ap(1,1,i) ph(:,2,i)/ap(2,1,i) ph(:,3,i)/ap(3,1,i)];
end
for i=N+1
Fc(:,:,i)=[-T1*f(:,1,i) -T2*f(:,2,i) -T3*f(:,3,i)];
end
for i=2:N
Fc(:,:,i)=[T1*f(:,1,i+1) T2*f(:,2,i+1) T3*f(:,3,i+1)]+[-T1*f(:,1,i)-T2*f(:,2,i) -T3*f(:,3,i)];
end
for i=2:N+1
fa(:,:,i)=Fc(:,1,i)+Fc(:,2,i)+Fc(:,3,i);
end
for i=2:N+1
Ma(:,:,i)=cross(r(:,:,1),Fc(:,1,i))+cross(r(:,:,2),Fc(:,2,i))+cross(r(:,:,3),Fc(:,3,i));
end
for i=2:N+1
feq(:,:,i)=fa(:,:,i) +Fg(:,:,i);
Meq(:,:,i)=Ma(:,:,i)+Me(:,:,i);
end
for j=1:(3*N)
for i=2:N+1
F(j,:,:)= dot(Meq(:,:,i),wk(:,j,i))+dot(feq(:,:,i),vk(:,j,i));
end
end
shahin hashemi
shahin hashemi 2017-12-23
this is my cod and as its is obvious my main variable is x but i must define xd but i remove them after some calculations with "collect" and "coeffs" commend
shahin hashemi
shahin hashemi 2017-12-23
x0=[0;0.1;0];
options = optimoptions('fsolve','Display','iter');
[x,fval] = fsolve(@consnt6,x0,options)
shahin hashemi
shahin hashemi 2017-12-23
my final F is 3*1 matrix that only contain x1 x2 x3

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 采纳的回答

Walter Roberson
Walter Roberson 2017-12-23
编辑：Walter Roberson 2017-12-23

0 个投票

It is not possible to do what you are asking to do.
I already told you what you need to do to solve this: you need to run your code symbolically, and then use matlabFunction to convert the resulting symbolic expressions to function handles.

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shahin hashemi
shahin hashemi 2017-12-23
thank you mr walter for your solutions
but i dont understand what do you mean by "I already told you" and i really be apreciated if you could gave me an example
i search the net and i face with smth like this :
function y = example373677
y = fsolve(@mysubfun, 3);
function z = mysubfun(q)
x = sym('x');
r = x.^3-2*x-5;
z = double(subs(r, q));
i that what you mean ?
Walter Roberson
Walter Roberson 2017-12-23
x = sym('x', [1 3], 'real');
fun_sym = consnt7(x);
fun = matlabFunction(fun_sym, 'vars', {x.'});
x0=[0;0.1;0];
options = optimoptions('fsolve','Display','iter');
z = fsolve(fun, x0, options)
Note: there are a number of different solutions even with x(1) = 0 and x(2) = 0
shahin hashemi
shahin hashemi 2017-12-24
dear mr walter
did you run the cod with :
x = sym('x', [1 3], 'real');
fun_sym = consnt7(x);
fun = matlabFunction(fun_sym, 'vars', {x.'});
x0=[0;0.1;0];
options = optimoptions('fsolve','Display','iter');
z = fsolve(fun, x0, options)
and if you run could you plz tell me where shold i put them ?
Walter Roberson
Walter Roberson 2017-12-24
Yes, I ran that code, and got back numeric values in z.
This code should replace your current
x0=[0;0.1;0];
options = optimoptions('fsolve','Display','iter');
[x,fval] = fsolve(@consnt6,x0,options)
shahin hashemi
shahin hashemi 2017-12-24
thank you mr walter finaly my problem solved with your help
happy new year with best wishes

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更多回答（1 个）

Matt J
Matt J 2017-12-24
编辑：Matt J 2017-12-24

0 个投票

but i mention again that my final equation doesnt contain any of those symbolic var
But your final F is generated from calculations with these variables, so they inherit their symbolic type. At no point in your code, do you do anything to convert from symbolic to double. When I run your function on some sample input, I obtain
>> class(consnt7([1,1,1]))
ans =
'sym'
So, as you can see, your output is still of type sym.
but i remove them after some calculations with "collect" and "coeffs" commend
Nope. The output of these commands are still of type sym. I explained to you here (and you thanked me emphatically) that the commmand double() was the way to convert from sym to double.

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shahin hashemi
shahin hashemi 2017-12-24
thank you mr matt for your answer
and i should say i do what you say befor and i can run cod for N=1
function F = consnt4(x)
m=1.669e-3;
jx=5.743e-14;
E=2.1e11;
O=12.5e-3;
jz=1.149e-13;
G=8e10;
L=3e-3;
g=9.81;
N=3;
T1=2;
T2=1;
T3=0.5;
r1=[1*O;0;0;];
r2=[(-1/2)*O;(sqrt(3))*O/2;0];
r3=[(-1/2)*O;-(sqrt(3))*O/2;0];
pl=L*[(cos(x(1))*(1-cos(x(2))))/x(2) (sin(x(1))*(1-cos(x(2))))/x(2) sin(x(2))/x(2)]';
wk=[0 -sin(x(1)) cos(x(1))*sin(x(2));0 cos(x(1)) sin(x(1))*sin(x(2));1 0 cos(x(2))];
vk=L*[-sin(x(1))*((1-cos(x(2)))/x(2)) (cos(x(1))/x(2)^2)*(sin(x(2))*x(2)-(1-cos(x(2)))) 0;cos(x(1))*((1-cos(x(2)))/x(2)) (sin(x(1))/(x(2)^2))*((sin(x(2))*x(2))-(1-cos(x(1)))) 0;0 (cos(x(2))*x(2)-sin(x(2)))/(x(2)^2) 0];
R=[cos(x(1))*cos(x(2))*cos(x(3))-sin(x(1))*sin(x(3)) -cos(x(1))*cos(x(2))*sin(x(3))-sin(x(1))*cos(x(3)) cos(x(1))*sin(x(2));sin(x(1))*cos(x(2))*cos(x(3))+cos(x(1))*sin(x(3)) -sin(x(1))*cos(x(2))*sin(x(3))+cos(x(1))*cos(x(3)) sin(x(1))*sin(x(2));-sin(x(2))*cos(x(3)) sin(x(2))*sin(x(3)) cos(x(2))];
Mb=E*jx*((x(2))/L)*[1 0 0;0 1 0;0 0 1]*[-sin(x(1));cos(x(1));0];
Mt=-G*jz*(x(1)+x(3))*R(:,3)/L;
Me=Mb+Mt;
Fg=-m*g*[1;0;0];
ph(:,1)=[pl+R*r1-r1];
ph(:,2)=[pl+R*r2-r2];
ph(:,3)=[pl+R*r3-r3];
ap=[sqrt(ph(1,1)^2+ph(2,1)^2+ph(3,1)^2);sqrt(ph(1,2)^2+ph(2,2)^2+ph(3,2)^2);sqrt(ph(1,3)^2+ph(2,3)^2+ph(3,3)^2)];
f=[ph(:,1)/ap(1,1) ph(:,2)/ap(2,1) ph(:,3)/ap(3,1)];
Fc=[-T1*f(:,1) -T2*f(:,2) -T3*f(:,3)];
fa=Fc(:,1)+Fc(:,2)+Fc(:,3);
Ma=cross(r1,Fc(:,1))+cross(r2,Fc(:,2))+cross(r3,Fc(:,3));
feq=fa +Fg;
Meq=Ma+ Me;
F(1,:)= [dot(Meq,wk(:,1))+dot(feq,vk(:,1))];
F(2,:)= [dot(Meq,wk(:,2))+dot(feq,vk(:,2))];
F(3,:)= [dot(Meq,wk(:,3))+dot(feq,vk(:,3))];
and for fsolve :
x0=[0;0.1;0];
options = optimoptions('fsolve','Display','iter');
[x,fval] = fsolve(@consnt4,x0,options)
and now i try for N>1 that cause to appear xd
and now when i try your solution i mean using double(sub()) again i face with same error and i think i cant use syms in my main function that call by f solve and i should do it in smth like sub functions ?

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