mapSolution broken in R2019b?
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In R2019a, the following code works as intended,
%% Define the variables
x=optimvar('x',{'x1','x2'},'LowerBound',[-100,-200]);
y=optimvar('y',1,3,'LowerBound',[0 0 0],'UpperBound',[+300,+400,+500]);
%% Define some constraints
C.inequ=2*sum(y)+sum(x)<=1000;
C.equ=5*sum(x)==100;
prob=optimproblem('Constraints',C,'Objective',sum(x)+sum(y));
idx=mapSolution(prob,1:5)
resulting in the output,
idx =
struct with fields:
x: [1 2]
y: [1 2 3]
Something must have been changed in R2019b/R2020a, however, because I instead get an error:
Not enough input arguments.
Error in optim.internal.problemdef.ProblemImpl/mapSolution
Error in test (line 12)
idx=mapSolution(prob,1:5)
Were there any intentional changes in the behavior of the mapSolution function, and if so how do I get the code above to work in current Matlab?
3 个评论
Walter Roberson
2020-8-15
编辑：Matt J
2020-8-16
shows a number of mandatory inputs
Matt J
2020-8-16
Walter Roberson
2020-8-16
Darn, it is a .p file so we can't read it.
采纳的回答
Paul Kerr-Delworth
2020-8-28
Hi Matt and Walter,
Firstly Matt, many apologies that you've run into this unintended behavior. Also, many thanks to you both for looking into this and flagging it up.
What has happened here? The short answer is that mapSolution was made an internal function in R2019a and replaced with varindex. Once we made mapSolution internal, we repurposed it in R2019b leading to the internal error you encountered. We will tidy up the error and add a note in the documentation pointing you to varindex
Matt's original code works with varindex
%% Define the variables
x=optimvar('x',{'x1','x2'},'LowerBound',[-100,-200]);
y=optimvar('y',1,3,'LowerBound',[0 0 0],'UpperBound',[+300,+400,+500]);
%% Define some constraints
C.inequ=2*sum(y)+sum(x)<=1000;
C.equ=5*sum(x)==100;
prob=optimproblem('Constraints',C,'Objective',sum(x)+sum(y));
idx = varindex(prob);
Resulting in the output
idx =
struct with fields:
x: [1 2]
y: [3 4 5]
Also, varindex allows you to get the variable index by name, e.g.
idx = varindex(prob, 'y')
Resulting a double as the output
idx =
3 4 5
Matt, may I ask if you were aware of varindex? Also, is there anything in mapSolution that you are relying on that varindex doesn't provide?
Thanks again for flagging this and hope varindex helps!
Cheers,
Paul
Documentation for varindex:
5 个评论
Matt J
2020-8-28
Paul Kerr-Delworth
2020-8-28
Hi Matt,
Thanks for accepting the answer and for your comment - much appreciated!
Just to clarify, I guess ideally you'd like mapSolution to work as it did in R2019a and earlier. Would you be happy if there were another function that mapped the solution output from the Solver-Based interface to a solution structure that is returned from the Problem-Based interface? Or, do you really just want mapSolution back?
In the meantime, would this solution work for you? You'd need to add this function to your path and replace all your mapSolution calls to mattMapSolution, but this should reproduce mapSolution.
function solstruct = mattMapSolution(prob, solvec)
idx = varindex(prob);
varNames = fieldnames(idx);
for i = 1:length(varNames)
solstruct.(varNames{i}) = solvec(idx.(varNames{i}));
end
Cheers,
Paul
Paul Kerr-Delworth
2020-9-1
编辑：Paul Kerr-Delworth
2020-9-1
Hi Matt,
Many thanks for the clarification, that's really helpful for us.
For a backwards compatible solution that can work, you can add your own version of varindex to the path as a separate function
function solstruct = varindex(prob)
if ~isa(prob, 'optim.problemdef.OptimizationProblem')
error('First input to VARINDEX must be an OptimizationProblem');
end
if verLessThan('matlab', '9.6')
error('This function is intended for R2017b - R2018b. Make this a separate function on the path.')
end
N = sum(structfun(@numel, prob.Variables));
solstruct = mapSolution(prob, 1:N);
end
Now for R2017b-R2018b, this function will be called as varindex doesn't exist. From 19a onwards the shipping OptimizationProblem method will be called as it is higher in the precedence order than your varindex.
Would you be happy to move to varindex with this solution?
Cheers.
Paul
Matt J
2020-9-1
更多回答（1 个）
1 个评论
Walter Roberson
2020-8-25
Internal code does not do detailed argument checking for performance reasons.
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