lsqnonlin projectBox error when using OutputFcn
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Hello,
I am trying to check the number of iterations and residuals after each iteration of lsqnonlin. I have more unknowns than equations and have set it to use the levenberg-marquardt algorithm. I also made the following output function:
function [stop]=residual_check_fun(x,optimValues,state)
keyboard
iteration=optimValues.iteration;
residual=optimValues.residual;
if iteration>5 && residual>10000
stop=true;
else
stop=false;
end
end
This function works when I have one equation and one unknown, but does not work for more unknowns than equations. The error I am getting is the following:
Unable to perform assignment because the left and right sides have a different number of elements.
Error in projectBox (line 39)
dx(activeLB) = lb(activeLB) - x(activeLB);
Error in levenbergMarquardt>@(x,dx)projectBox(x,dx,lb,ub) (line 125)
project = @(x,dx) projectBox(x,dx,lb,ub);
Error in levenbergMarquardt>computeFirstOrderOpt (line 385)
a = norm(project(XOUT,-gradF),Inf);
Error in levenbergMarquardt>callOutputAndPlotFcns (line 410)
optimValues.firstorderopt = computeFirstOrderOpt(project,xOutputfcn,gradF);
Error in levenbergMarquardt (line 147)
[optimValues, stop] = callOutputAndPlotFcns(outputfcn,plotfcns,caller,reshape(XOUT,xShape),...
Error in lsqncommon (line 186)
levenbergMarquardt(funfcn,xC,lb,ub,flags.verbosity,options,defaultopt,initVals.F,initVals.J, ...
Error in lsqnonlin (line 260)
lsqncommon(funfcn,xCurrent,lb,ub,options,defaultopt,optimgetFlag,caller,...
0 件のコメント
回答 (2 件)
Alan Weiss
2022 年 3 月 9 日
The error is because optimValues.residual is a vector, not a scalar. Possibly you want to write norm(optimValues.residual).
Alan Weiss
MATLAB mathematical toolbox documentation
Bianca Romanski
2022 年 8 月 23 日
編集済み: Bianca Romanski
2022 年 8 月 23 日
tl;dr Try updating your Matlab version.
Hello Dennis,
I got exactly the same error as you did. To understand the error better, I reproduced it with some code as simple as possible:
% Call optimization
x0 = [0 1];
options = optimoptions(@lsqnonlin, 'Algorithm','levenberg-marquardt','OutputFcn',@outfun,...
'Display','iter');
[xsol,fval] = lsqnonlin(@objfun,x0,[-1 -1],[1 1],options);
% [xsol,fval] = lsqnonlin(@objfun,x0,[],[],options);
function stop = outfun(x,optimValues,state)
stop = false;
end
function f = objfun(x)
f = exp(x(1))*(4*x(1)^2 + 2*x(2)^2 + 4*x(1)*x(2) +...
2*x(2) + 1);
end
I found out, that the projectBox error occurs only when constraints are used. Without constraints the script worked perfectly fine. As I couldn't think about any reason why output functions only work for unconstraint problems, I was wondering whether this might be a bug in the Matlab function. As bugs are fixed sometimes, I updated my Matlab and ran the above code in Matlab 2022a (instead of 2020b) and it worked! Maybe updating your Matlab version will also solve your issue. :)
3 件のコメント
Bianca Romanski
2022 年 8 月 24 日
I changed the 5th line, so that upper and lower bounds are column vectors.
[xsol,fval] = lsqnonlin(@objfun,x0,[-1; -1],[1; 1],options);
That didn't change anything, the same error occurs.
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