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POMatlab Get Property function causing performance problems
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copied!<p>I have a property in one of the classes I created that currently has an unnecessary get function associated with it. I initially made it to do useful things before returning the value, but now I just need the property value, so the get function has been reduced to this:</p> <blockquote> <pre><code> function value = get.error(obj) value = obj.error; end </code></pre> </blockquote> <p>Now, seeing as this code is completely redundant, I decided to delete the get function all together, but this leads to an <em>incredible</em> slowdown in one section of my code where the 'error' property is accessed repeatedly.</p> <p>In this section of code, the profiler doesn't <em>explicitly say</em> that the missing get function is the cause of the problem (it says all of the time is wasted at the 'end' of a 'for' loop), but when I add the functionally useless code back in, the performance problem goes away.</p> <p>Why would deleting this useless get function slow down my code?</p> <p>EDIT: I've isolated the problem enough to post some code samples.</p> <p>Here's a dummy version of the method call that has the problem: <img src="https://i.stack.imgur.com/hv2Cp.png" alt="enter image description here"></p> <p>Here's the code profile without the useless getter: <img src="https://i.stack.imgur.com/a6Rto.png" alt="enter image description here"></p> <p>and with the magical useless getter: <img src="https://i.stack.imgur.com/ASOhp.png" alt="enter image description here"></p> <p>Note that the requires for the performance appear to be as follows:</p> <ol> <li><p>use some property of my 'pool' object in a computation set to any variable. The 'error' property is the one that caught my attention, but the bug happens with all properties in the same situation.</p></li> <li><p>the computation involves anything, even '.* 0' causes this slowdown, but a single term being set is slowdown free (e.g. obj.pools(i).delta = obj.pools(i).error)</p></li> </ol> <p>EDIT 2:</p> <p>Here's the full pool class; perhaps it'll help:</p> <pre><code>classdef pool < handle properties name; unit_count; activation; net_input = 0; %all projections now incoming projections = []; error; % same is dEd net for rbp target; clamped_error = false; delta; clamped_activation = 0; %0 no clamp, 1 soft clamp, 2 hard clamp copyback = false; copy_from; type = 'hidden'; activation_history; error_history; end methods function obj = pool(name,count,type,copy_from) obj.name = name; assignin('caller', name, obj); obj.unit_count = count; obj.error = zeros(1,count); obj.target = zeros(1,count); obj.delta = zeros(1,count); obj.activation = zeros(1,count); obj.net_input = zeros(1,count); obj.activation_history(:,1) = zeros(1,count); obj.error_history(:,1) = zeros(1,count); if nargin > 2 obj.type = type; if nargin == 4 obj.clamped_activation = 2; obj.activation = ones(1,count)/2; obj.copy_from = copy_from; obj.copyback = true; end else obj.type = 'hidden'; end switch obj.type case 'input' obj.clamped_activation = 2; case 'output' obj.clamped_error = true; case 'bias' obj.clamped_activation = 2; obj.activation = 1; case 'hidden' end end function proj = connect(obj,send_pool,proj_var) %see if you need a new projection or if the user provided one if nargin == 2 proj = projection(obj, send_pool); else proj = proj_var; end obj.projections = [obj.projections struct('from',send_pool,'using',proj)]; end function value = get.error(obj) value = obj.error; end end end </code></pre>

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