我有一个句柄类:
classdef A<handle
properties
a;
end
methods
function obj = A(a)
obj.a=a;
end
end
end
我有一个 A
对象的元胞数组:
arr={};
for i=1:3
arr{i}=A(i);
end
我想做的是将该元胞数组传递给 parfor
循环,以便每个对象的值都会发生变化:
parfor i=1:3
arr{i}.a=i*5;
end
然而,这段代码根本没有改变arr
。事实上,here它指出
Changes made to handle classes on the workers during loop iterations are not automatically propagated to the client.
我怎样才能克服这个问题?
最佳答案
一个有趣的问题;我实际上从未遇到过这个问题。了解关于 parfor
限制的一切总是好的,所以我做了一些谷歌搜索并想出了 this :
I have received an answer to this issue from technical support. Apparently the Mathworks regard it as a 'feature' that changes to objects are not returned - though I can't see that it's a very useful feature. Anyway, the way to get modified class properties returned from a parfor loop is to make an explicit change which can be recognised by parfor. Here are two examples which work for the above example object:
parfor n = 1:num exArray(n).data = n:n+5; end
or
parfor n = 1:num temp = exArray(n); setData(temp,n:n+5); exArray(n) = temp; end
Actually, if you change any object property it also seems to work. So for example this also works, if there is a second property data2 which is set explicitly, both data and data2 are correctly returned:
parfor n = 1:num setData(exArray(n),n:n+5); exArray(n).data2 = n:n+5; end
示例对象由
给出classdef Example < handle
properties
data
end
methods
function obj = Example(data)
obj.data = data;
end
function setData(obj,data)
obj.data = data;
end
function data = getData(obj)
data = obj.data;
end
end
end
并且数组被简单地初始化为
% Initialise array of objects
for n = 1:num
exArray(n) = Example(zeros(1,6));
end
关于matlab - parfor 和句柄类,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12200236/