Ticket #36 (closed defect: invalid)
RMS command: difference to older versions
Reported by: | Franz | Owned by: | MarcusWalther |
---|---|---|---|
Priority: | high | Milestone: | |
Component: | SH | Severity: | major |
Keywords: | Cc: |
Description
From user's mailing list, see message http://list.seismic-handler.org/pipermail/users/2011-May/000092.html
There's a huge difference between recent new and old version using ShRms. The old result seems to be correct.
SeismicHandler version 5.0a 13-Jul-2006, Copyright (C) 2006 |sh> rms 1 0 3600 rms: 9.336159e+00 SeismicHandler version 5.5 February-2011, Copyright (C) 2011 |sh> rms 1 0 3600 rms: 2.505154e+03
Attachments
Change History
comment:2 Changed 13 years ago by MarcusWalther
This chance seems to be related to the fix in r373. Since the symbol "mean" was uninitialized, the result of RMS was unpredictable.
comment:3 Changed 13 years ago by MarcusWalther
For the records another result of CRESHARP test:
The value for the 2006 version is rms: 9.304403e-03
comment:4 follow-up: ↓ 5 Changed 13 years ago by MarcusWalther
Explaining the difference between 2008 and 2011:
If "main" was initialized with 0 at runtime, the summed values where not divided by sample number and square root was also not taken. If we catch up on these operations, we get in case of the CRESHARP test (1000 samples):
>>> import math >>> "%e" % math.sqrt(8.657193e+01/1000) '2.942311e-01'
This is the result of 2011 version. The result from 2006 cannot be explained that way.
comment:5 in reply to: ↑ 4 Changed 13 years ago by MarcusWalther
Replying to MarcusWalther:
If "main" was initialized with 0 at runtime, ...
Of course I meant "mean".
Changed 13 years ago by MarcusWalther
- Attachment cf22c76e0c33c4fb96262638a28bd52b.png added
Wikipedia RMS formula
The difference also exists between version 2008 and 2011:
So it should be related to a chance in or after 2008...