It certainly isn't particularly fast, but it takes about 21s on my computer (R2019a) to create a 1 million elements object array and the mat files is only around 38 kB. Nowhere near 15 minutes.
You're still better off having a scalar class though. I'm a bit unclear on where you're stuck though. Having some example class code may help clarify.
For what is worth, this is the class I tested with (not production worthy code at all):
classdef gridelem < handle
properties (SetAccess = private)
ID(:, 1) uint64;
Location(:, 3) double;
end
methods
function this = gridelem(locations)
if nargin~= 0 %nargin == 0 happens when the array is created on the next line.
this(size(locations, 1), 1) = gridelem; %allocate object array, before filling up location
locations = num2cell(locations, 2);
[this.Location] = locations{:};
end
IDs = num2cell(1:numel(this)); %fill up IDs even if no location was provided.
[this.ID] = IDs{:};
end
end
end
%testing class
g = gridelem(rand(1e6, 3))
