Opened 11 years ago
Closed 11 years ago
#5572 closed Bugs (fixed)
regression in lagged_fibonacci607
| Reported by: | Eric Niebler | Owned by: | Steven Watanabe |
|---|---|---|---|
| Milestone: | Boost 1.47.0 | Component: | random |
| Version: | Boost Release Branch | Severity: | Showstopper |
| Keywords: | lagged_fibonacci607 | Cc: |
Description
Many accumulators tests are now failing on both trunk and release. I have tracked it down to recent changes in Boost.Random. I don't know for how long this has been happening.
The accumulators tests use the lagged_fibonacci607 random number generator. The tests work by sending a large amount of random data through various statistical accumulators and checking that the results are within a certain tolerance of what they would be if the data were actually random. In Boost 1.45 and previous versions, this worked. (I haven't tested 1.46.) Trunk and release are hosed, leading me to suspect that this random number generator is no longer producing sufficiently random data.
I have verified this by replacing boost/random on trunk with the one from 1.45. With this change, the accumulators tests pass.
Steven, this seems like a regression. Can you look into this?
Change History (2)
comment:1 by , 11 years ago
| Owner: | changed from to |
|---|
comment:2 by , 11 years ago
| Resolution: | → fixed |
|---|---|
| Status: | new → closed |
The problem is not that the output is not sufficiently random, but that it changed. The Accumulators tests were tuned for the exact output that lagged_fibonacci607 used to produce. I adjusted the tests to so that they now pass again.