elapsedtimer

classdef elapsedtimer < handle
%
% Print elapsed time and extrapolate remaining time of a lengthy
% computation. Smarter than tic and toc, but not as complex as the Matlab 
% timer class. Currently there can be only one elapsedtimer running.
%
% Easiest:
%   Before computation: etimer = elapsedtimer;
%   At each step: steptimer(etimer);
%
% Print only every nth step, when computation has many steps, or steps are short:
%   Before computation: etimer = elapsedtimer(n);
%
% When we know there will be 100 steps and we want remaining time displayed:
%   Before computation: etimer = elapsedtimer([],100);
%
% If there are 100 steps but we only want to print every 10th:
%   Before computation: etimer = elapsedtimer(10,100);
%
% Matt Caywood
% version 0.1: published 2010.07.20
% version 0.2: made object-oriented, simplified calling 2010.07.29
% version 0.21: fixed initialization bugs

properties (SetAccess = private)
   tstart = 0;
   step = 0;
   totalsteps = 0;
   modulo = 1;
end 

methods
   function etimer = elapsedtimer(modulo,totalsteps)
       if exist('totalsteps','var'), etimer.totalsteps = totalsteps; else etimer.totalsteps = 0; end
       if exist('modulo','var') && ~isempty(modulo), etimer.modulo = modulo; else etimer.modulo = 1; end
       etimer.tstart = now;
       etimer.step = 0;
   end

   function steptimer(etimer)
       etimer.step = etimer.step + 1;

       if mod(etimer.step,etimer.modulo) == 0
           tnow = now;
           telapsed = tnow - etimer.tstart;
           tstepmean = telapsed / etimer.step;
           tremaining = tstepmean * max(0,etimer.totalsteps - etimer.step);
           
           elapsedstr = datestr(telapsed,13);
           stepmeanstr = datestr(tstepmean,13);

           if etimer.totalsteps > 0
                remainingstr = datestr(tremaining,13);
                fprintf('Elapsed time: %s Time per step: %s Time remaining: %s\n',elapsedstr,stepmeanstr,remainingstr);
           else
                fprintf('Elapsed time: %s Time per step: %s\n',elapsedstr,stepmeanstr);
           end
       end

   end
end

end