On 18 Aug 2009, at 19:52, joel wrote:
It means what it says, for the two functions you are timing there is no measurable difference in execution time that cannot be explained by chance. So, if you think A is faster than B or B is faster than A, you are mistaken.
The final figure for example, -5.22 --- +4.15, indicates that with a 95% chance the speedup of A relative to B lies between those extremes. Since these extremes clearly include zero you can't say there is a speedup. The best point estimate of the speedup is 0.053% (naff all!). This means A and B have the same execution time most of the time
Edward Grace wrote: then ?
No, it's more subtle than that. Almost all of the time there will be a difference between A and B, however this difference is just 'noise' around zero. In order for there to be a meaningful difference the natural random variations of the differences should be significantly different from zero. -ed