Graphics argument validation for function in parfor loop
Mostrar comentarios más antiguos
I have a function that I'd like to run serially but also sometimes inside a parfor loop, with the ability to optionally plot output. Understandably, I can't plot or modify graphics within a parpool thread, but I find even having unused relevant argument validation that draws from matlab.graphics.axis.Axes class properties causes a parallel:threadpool:NonConcurrentLibrary error to be thrown during parallel execution. Attached is a code snippet demonstrating what I mean.
I suppose I have two questions. First, is this expected behaviour, given that args is not even invoked in the body of the function? Second, is there any way to retain automatic argument validation for an axis object that plays nicely with parfor, in cases where these arguments are used conditionally and never during parallel execution?
function ArgValidationParForTest()
pool = gcp();
fprintf('Parallel pool initialised with %d workers\n', pool.NumWorkers)
ntests = 10;
parfor i = 1:ntests
TestFunc()
end
end
function TestFunc(args)
arguments
args.?matlab.graphics.axis.Axes
end
fprintf('Called\n')
end
Respuesta aceptada
If you use a process-based pool, it will work --
parpool('Processes')
Más respuestas (1)
Second, is there any way to retain automatic argument validation for an axis object that plays nicely with parfor, in cases where these arguments are used conditionally and never during parallel execution?
You would probably have to hand off to a separate validation routine,
function TestFunc(varargin)
fprintf('Called\n')
args=handOff(varargin{:});
end
function args=handOff(varargin)
p = gcp('nocreate');
args=[];
if isempty(p) || ~isa(p,'parallel.ThreadPool')
args=validateGraphics(varargin{:});
elseif ~isempty(varargin)
error 'Handle graphics aren''t supported in threadpools'
end
end
function args=validateGraphics(args)
arguments
args.?matlab.graphics.axis.Axes
end
end
2 comentarios
Jake
el 20 de Mayo de 2026 a las 8:46
You can recover some of the benefits of CLI by adding an explicit argument list, i.e., by copy-pasting the following auto-generated argument list into your TestFunc arguments block. This block knows only the names of the name/value parameters, and not any of the defaut values and type restrictions. So you would still need to use the handOff function to do the validation proper. However, it at least it will complete the parameter names for you.
disp(char( " args."+properties("matlab.graphics.axis.Axes") ))
Categorías
Más información sobre Parallel for-Loops (parfor) en Centro de ayuda y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
