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Render 1D column of Optimizati​onVariable​/Optimizat​ionExpress​ion objects to string?

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FM
FM on 22 Apr 2021
Edited: FM on 28 May 2021
In Matlab 2019a, I have a table wherein a column `IFpvfd` is an `OptimizationVariable` array:
myTable = table( [1:3]' , ...
optimvar( 'IFpvfd' , 3 , 1 , 'Type','integer' , ...
'LowerBound',0 , 'UpperBound',1 ) , ...
'VariableNames' , {'RowNbr' 'IFpvfd'} )
myTable = 3×2 table
RowNbr IFpvfd
______ ___________________________________________
1 [1x1 optim.problemdef.OptimizationVariable]
2 [1x1 optim.problemdef.OptimizationVariable]
3 [1x1 optim.problemdef.OptimizationVariable]
showvar( myTable.IFpvfd )
[ IFpvfd(1) ]
[ IFpvfd(2) ]
[ IFpvfd(3) ]
I want to add a column `IFpvfd2` that shows the `OptimizationVariable` more readably, either as a string array or cell array of character arrays:
RowNbr IFpvfd IFpvfd2
______ ___________________________________________ _________
1 [1x1 optim.problemdef.OptimizationVariable] IFpvfd(1)
2 [1x1 optim.problemdef.OptimizationVariable] IFpvfd(2)
3 [1x1 optim.problemdef.OptimizationVariable] IFpvfd(3)
I was hoping that there was a function to do this using arrayfun:
myTable.IFpvfd2 = arrayfun( @SomeFunc , myTable.IFpvfd )
For `SomeFunc`, I don't think I can use an anonymous function based on `sprintf` because the formatting string only accepts primitive data:
@(x) sprintf( 'Some Formatting String' , x )
I can't use `showvar` or `writevar`, as they send the output to either console and a text file without providing a return argument.

Accepted Answer

Walter Roberson
Walter Roberson on 22 Apr 2021
myTable = table( [1:3]' , ...
optimvar( 'IFpvfd' , 3 , 1 , 'Type','integer' , ...
'LowerBound',0 , 'UpperBound',1 ) , ...
'VariableNames' , {'RowNbr' 'IFpvfd'} )
myTable = 3×2 table
RowNbr IFpvfd ______ ___________________________________________ 1 [1×1 optim.problemdef.OptimizationVariable] 2 [1×1 optim.problemdef.OptimizationVariable] 3 [1×1 optim.problemdef.OptimizationVariable]
myTable.IFpvfd2 = rowfun( @SomeFunc , myTable, 'InputVariables', 'IFpvfd' )
myTable = 3×3 table
RowNbr IFpvfd IFpvfd2 Var1 ______ ___________________________________________ _________ 1 [1×1 optim.problemdef.OptimizationVariable] IFpvfd(1) 2 [1×1 optim.problemdef.OptimizationVariable] IFpvfd(2) 3 [1×1 optim.problemdef.OptimizationVariable] IFpvfd(3)
function S = SomeFunc(OV)
warnstate = warning('off', 'MATLAB:structOnObject');
OVS = struct(OV);
warning(warnstate);
S = categorical(sprintf("%s(%d)", OVS.Name, OVS.OptimExprImpl.getVarIdx));
end
Note: it did not work to create SomeFunc as an anonymous function: for reasons I do not understand, MATLAB claimed there was no function with that name that was applicable to that datatype.
  5 Comments
FM
FM on 23 Apr 2021
That's quite some sleuthing. Some tricks I will have to keep in my back pocket in case I'm against the wall in the future.
Thanks again!

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More Answers (1)

FM
FM on 28 May 2021
Edited: FM on 28 May 2021
Here is one solution for a 1D column of OptimizationVariable objects and another solution for a 1D column of OptimizationExpression objects. The latter requires a temporary variable and can't be done in one statement. However, it is able to handle both cases. If I write an source m-file for the conversion function, therefore, I would use the 2nd scheme.
Both schemes assume a 1D column of objects. If the table column consists of a 2D array (which it can!), more sophisticated coding is needed.
% Scheme 1: Test data table with column of OptimizationVariable objects
myTable = table( [1:3]' , ...
optimvar( 'IFpvfd' , 3 , 1 , 'Type','integer' , ...
'LowerBound',0 , 'UpperBound',1 ) , ...
'VariableNames' , {'RowNbr' 'IFpvfd'} );
% Scheme 1: Render OptimizationVariable column into strings
myTable.strIFpvfd = splitlines( string( regexprep( ...
strtrim( evalc( 'showvar( myTable.IFpvfd )' ) ) , ...
'[ \[\]]' , '' ) ) );
myTable = 3×3 table
RowNbr IFpvfd strIFpvfd
______ ___________________________________________ ___________
1 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(1)"
2 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(2)"
3 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(3)"
% Scheme 2: Test data table with column of OptimizationExpression objects
myTable.IFpvfd2 = 0 + myTable.IFpvfd;
% Scheme 2: Render OptimizationExpression column into strings
noisyIFpvfd2 = splitlines( string( regexprep( ...
strtrim( evalc( 'showexpr( myTable.IFpvfd2 )' ) ), ...
'[ \[\]]' , '' ) ) );
myTable.strIFpvfd2 = noisyIFpvfd2(3:4:end)
myTable = 3×5 table
RowNbr IFpvfd strIFpvfd IFpvfd2 strIFpvfd2
______ ___________________________________________ ___________ _____________________________________________ ___________
1 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(1)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(1)"
2 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(2)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(2)"
3 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(3)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(3)"
% Show that Scheme 2 also works with OptimizationVariable
noisyIFpvfd2 = splitlines( string( regexprep( ...
strtrim( evalc( 'showexpr( myTable.IFpvfd )' ) ), ...
'[ \[\]]' , '' ) ) );
noisyIFpvfd2(3:4:end)
ans = 3×1 string array
"IFpvfd(1)"
"IFpvfd(2)"
"IFpvfd(3)"
So the function is:
% strOptVarExpr.m
%----------------
% Convert 1D column of OptimizationVariable or OptimizationExpression
% objects into string representation of the symbolic representation
function strOut = strOptVarExpr( OptVarExpr )
strOut = splitlines( string( regexprep( ...
strtrim( evalc( 'showexpr( OptVarExpr )' ) ), ...
'[ \[\]]' , '' ) ) );
strOut = strOut(3:4:end);
end
The result is:
myTable.strIFpvfd = strOptVarExpr( myTable.IFpvfd );
myTable.strIFpvfd2 = strOptVarExpr( myTable.IFpvfd2 )
myTable = 3×5 table
RowNbr IFpvfd strIFpvfd IFpvfd2 strIFpvfd2
______ ___________________________________________ ___________ _____________________________________________ ___________
1 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(1)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(1)"
2 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(2)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(2)"
3 [1x1 optim.problemdef.OptimizationVariable] "IFpvfd(3)" [1x1 optim.problemdef.OptimizationExpression] "IFpvfd(3)"

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