Extract a value from MATLAB codistributed array - matlab

Question

I am attempting to build a distributed array of handle class objects in MATLAB and I would like to extract a specific handle from this vector for use on the command line. Given the code below, I would like the following to execute. I am running this on with two labs (matlabpool 2). The getValue function is what I need assistance with, thanks...
vec = buildArray;
h = getValue(vec,6);
h.id
ClassA.m:
A class that I would like to distribute in parallel.
classdef ClassA < handle
properties
id;
end
methods
function obj = ClassA(id)
obj.id = id;
end
end
end
buildArray.m:
A function to build codistributed array from local instances of ClassA.
function vec = buildArray
X(:,1) = 1:10; % create ids
gsize = size(X); % the global size
X = distributed(X); % distribute the ids
spmd
x = getLocalPart(X); % extract the local ids
local = cell(length(x),1); % create local storage for handles
% Create the class instances
for i = 1:length(x);
local{i} = ClassA(x(i));
end
% Build the codistributed array of handles
codist = codistributor1d(codistributor1d.unsetDimension, ...
codistributor1d.unsetPartition, gsize);
vec = codistributed.build(local,codist);
end
getValue.m:
This is the function that I need help with, currently it just displays what lab that contains the class with the specified id. I would like for it to return the handle so it may be used from the command line. How is this done?
function h = getValue(vec, id)
h = []; % just so it will not throw an error
spmd
local = getLocalPart(vec);
for i = 1:length(local);
if local{i}.id == id;
% Export h here
disp(['ID ', num2str(id), ' is on lab ', num2str(labindex)]);
break;
end
end
end

Answer 1

I was able to get my problem working using this for getValue.m, is there a better way?
function h = getValue(vec, id)
spmd
local = getLocalPart(vec);
idx = [];
for i = 1:length(local);
if local{i}.id == id;
idx = i;
break;
end
end
codist = codistributor1d(codistributor1d.unsetDimension, ...
codistributor1d.unsetPartition, [numlabs,1]);
IDX = codistributed.build(idx, codist);
end
c = gather(vec(IDX));
h = c{1};