Does the access method of a dependent property get called twice when the property is indexed into?

2 visualizaciones (últimos 30 días)
I have a class with a dependent property z. The method get.z(obj) returns a vector. This:
y = myObj.z(end);
appears to call get.z twice! The profiler shows 2 calls from the parent function and the run time is twice the expected run time. On the other hand:
x = myObj.z;
y = x(end);
calls get.z once and cuts down run time by half. Is this the intended behavior?
  1 comentario
Walter Roberson
Walter Roberson el 13 de Oct. de 2016
I speculate that one of the two is due to the "end", as it would need to find the size . This is just speculation on my part, though.

Iniciar sesión para comentar.

Respuesta aceptada

Naor Movshovitz
Naor Movshovitz el 13 de Oct. de 2016
Confirmed Walter's comment. Indeed the culprit is the keyword end. Here is minimal working example.
classdef Untitled
properties (Dependent)
x;
end
methods
function val = get.x(~)
fprintf('called\n')
val = [1,2,3];
end
end
end
>> obj = Untitled;
>> obj.x(2);
called
ans =
2
>> obj.x(end)
called
called
ans =
3
This behavior is mostly benign but occasionally troublesome, and easy to fix. I think this is a case for an m-lint message at least.

Más respuestas (0)

Categorías

Más información sobre Software Development Tools en Help Center y File Exchange.

Etiquetas

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by