error in running my optimization code

2023 7 19
1 个回答
更新时间：2023 7 20
4 次查看（30 天）

0 个投票

My code is throwing the following error in conversion which i cannot understand.
Code-
yexpected=table2array(Book65);
tspan=0:48;
yo=[0.2 0.05 0.539];
p=optimvar('p',7,"LowerBound",0,"UpperBound",30);
sol=ode45(@(t,y)kumar2004optimizer(t,y,p),tspan,yo);
myfcn = fcn2optimexpr(@kumar2004optimizer,p,tspan,y0);
obj = sum(sum((myfcn - yexpected).^2));
prob = optimproblem("Objective",obj);
p0.p = [3 25 25 12 1 0.5 1];
[psol,sumsq] = solve(prob,p0);
function dydt=kumar2004optimizer(t,y,p)
dydt=zeros(3,1);
dydt(1)=p(1)*y(1)*(1-y(1))-p(2)*y(1)*y(2);
dydt(2)=(p(3)*y(1)+y(3))*y(2)*(1-y(2))-y(2);
dydyt(3)=p(4)*(1+tanh((y(2)-p(5))/p(6)))-p(7)*y(3);
end
error-Unable to perform assignment because value of type
'optim.problemdef.OptimizationExpression' is not convertible to 'double'.

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回答（1 个）

Torsten
Torsten 2023-7-19

0 个投票

I assume that "yexpected" is a matrix of size 49x3.
yexpected=table2array(Book65);
p0 = [3 25 25 12 1 0.5 1];
sol = lsqnonlin(@(p)optimizer(p,yexpected),p0)
function res = optimizer(p,yexpected)
tspan=0:48;
y0=[0.2 0.05 0.539];
sol=ode45(@(t,y)kumar2004optimizer(t,y,p),tspan,y0);
res = sol - yexpected;
res = res(:);
end
function dydt=kumar2004optimizer(t,y,p)
dydt=zeros(3,1);
dydt(1)=p(1)*y(1)*(1-y(1))-p(2)*y(1)*y(2);
dydt(2)=(p(3)*y(1)+y(3))*y(2)*(1-y(2))-y(2);
dydt(3)=p(4)*(1+tanh((y(2)-p(5))/p(6)))-p(7)*y(3);
end

7 个评论
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Ayush Ranjan
Ayush Ranjan 2023-7-19
I tried running this but it says I cannot use '-' operator for structure
Torsten
Torsten 2023-7-19
编辑：Torsten 2023-7-19
"yexpected" must be a numerical array of size 49x3. See how you get "Book65" transformed to this class and size.
Ayush Ranjan
Ayush Ranjan 2023-7-20
I changed it to array but it shows the following error.
Operator '-' is not supported for operands of type 'struct'.
Error in optimizertrial>optimizer (line 8)
res = sol - yexpected;
Error in optimizertrial>@(p)optimizer(p,yexpected) (line 3)
sol = lsqnonlin(@(p)optimizer(p,yexpected),p0);
Error in lsqnonlin (line 218)
initVals.F = feval(funfcn{3},xCurrent,varargin{:});
Error in optimizertrial (line 3)
sol = lsqnonlin(@(p)optimizer(p,yexpected),p0);
Torsten
Torsten 2023-7-20
Before you pass "yexpected" to "lsqnonlin" by the line
sol = lsqnonlin(@(p)optimizer(p,yexpected),p0)
add the commands
class(yexpected)
size(yexpected)
and show us the output.
Ayush Ranjan
Ayush Ranjan 2023-7-20
ans =
'double'
ans =
26 3
This is what I got on the above commands
Torsten
Torsten 2023-7-20
编辑：Torsten 2023-7-20
What are the times where these 26x3 measurements were taken ? You have to specifiy them in "tspan" in place of the 0:48 you use at the moment.
And (I made a mistake here) use
[T,Y]=ode45(@(t,y)kumar2004optimizer(t,y,p),tspan,y0);
res = Y - yexpected;
instead of
sol=ode45(@(t,y)kumar2004optimizer(t,y,p),tspan,y0);
res = sol - yexpected;

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