"isfield" for hidden field in optimoptions

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Sargondjani
Sargondjani 2025-2-11
编辑： Matt J 2025-2-11
hi,
with Matlab 2019 it seems that:
options = optimoptions(@fsolve,'JacobPattern',speye(5))
isfield(options,'JacobPattern')
will return 0. But options.JacobPattern will return the speye(5).
I guess this is due to the hidden nature of JacobPattern. I want the code to check if the field is specified or not.
How do I do that?

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Walter Roberson
Walter Roberson 2025-2-11
编辑：Walter Roberson 2025-2-11
optimoptions returns on object of class optim.options.Fsolve not a struct.
You need to use
isprop(options,'JacobPattern')
However, more likely is that you want
isprop(options,'JacobPattern') && ~strcmp(options.JacobPattern), 'sparse(ones(Jrows,Jcols))')
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Walter Roberson
Walter Roberson 2025-2-11
I dunno. It is documented though
If S is not a structure array, then isfield returns 0.
I guess it makes it marginally easier to handle the situation where a function returns either a structure array or else []
Stephen23
Stephen23 2025-2-11
Such situations are also easily handled by the user: isstruct(S) && isfield(S,..)

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Matt J
Matt J 2025-2-11
编辑：Matt J 2025-2-11
Ran in:
One way:
options = optimoptions(@fsolve,'JacobPattern',speye(5));
isNonDefault = ~isequal(options.JacobPattern, optimoptions(@fsolve).JacobPattern )
isNonDefault = logical
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