Benchmark
=========

A developer friendly profiling class. Generates a simple html table as output indicating passed time and memory usage in human readable units. It supports multiple executions of profile blocks and calculates median values and average absolute median deviations over the entire series of measurements to indicate the spread of measurements.

Why does Benchmark show the median instead of the mean? "Calculation of medians is a popular technique in summary statistics and summarizing statistical data, since it is simple to understand and easy to calculate, while also giving a measure that is more robust in the presence of outlier values than is the mean".

Why average absolute median averages? "In statistics, the median absolute deviation (MAD) is a robust measure of the variability of a univariate sample of quantitative data". "Univariate refers to an expression, equation, function or polynomial of only one variable". Such as time, or memory. "Numerical data (or quantitative data) is data measured or identified on a numerical scale". Such as measurements of time and memory. So we should be better of using the median.

Why do you also show the mean? Because large differences between the median and the mean, means that the measurement data has outliers.

Caveats, this class is pretty simple. It does not try to exclude time spent "in itself". It does however automatically keep score of the total time from construction until the call to ->display().

sources, extra info:
- Median absolute deviation: http://en.wikipedia.org/wiki/Median_absolute_deviation
- Absolute deviation: http://en.wikipedia.org/wiki/Absolute_deviation
- Univariate: http://en.wikipedia.org/wiki/Univariate
- Numerical data: http://en.wikipedia.org/wiki/Quantitative_data

Example
=======

<?php
	include 'Benchmark.php';

	$benchmark = new Benchmark();
	$benchmark->start('section1');
	// do stuff
	$benchmark->stop('section1');
	$benchmark->start('section2');
	// do some stuff
	$benchmark->stop('section2');
	$benchmark->start('section2');
	// do some stuff again
	$benchmark->stop('section2');
	$benchmark->display();

Example Output:
section  #  |  Time                             |  Memory
            |  total mean  median   deviation   |  total mean  median   deviation
section2 2  |  0 ms  0 ms  0 ms     +/- 0 ms    |  512 B 256 B 256 B    +/- 0 B
section1 1  |  0 ms  0 ms  0 ms     +/- 0 ms    |  264 B 264 B 264 B    +/- 0 B
---------------------------------------------------------------------------------
total       |  1 ms                             |  2 kB