Bug 121566

Summary:	rms scalar is wrong
Product:	[Applications] kst	Reporter:	Enzo Pascale <enzo>
Component:	general	Assignee:	kst
Status:	RESOLVED FIXED
Severity:	normal
Priority:	NOR
Version First Reported In:	1.x
Target Milestone:	---
Platform:	unspecified
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Enzo Pascale 2006-02-08 01:10:52 UTC

Version:           1.2.0_svn_489756 (using KDE 3.3.2,  (3.1))
Compiler:          gcc version 3.3.5 (Debian 1:3.3.5-13)
OS:                Linux (i686) release 2.6.8-2-686-smp

in
void KstVector::updateScalars()

it is

_scalars["sigma"]->setValue(sumsq = sqrt((_scalars["sumsquared"]->value() - sum * sum / double(_nsum)) / double(_nsum-1)));
_scalars["rms"]->setValue(sqrt(sumsq/double(_nsum)));


it should be
_scalars["rms"]->setValue(sqrt(_scalars["sumsquared"]->value()/double(_nsum)));

Comment 1 George Staikos 2006-02-08 05:33:38 UTC

SVN commit 506997 by staikos:

correct RMS
Looks like a refactoring gone wrong...  Ok for 1.2.0 and trunk?
CCBUG: 121566


 M  +2 -2      kstvector.cpp  


--- branches/kst/hfi_calib/kst/kst/kstvector.cpp #506996:506997
@@ -195,9 +195,9 @@
 
     if (_nsum >= 2) {
       double sum = _scalars["sum"]->value();
-      double sumsq;
+      double sumsq = _scalars["sumsquared"]->value();
       _scalars["mean"]->setValue(_mean = sum/double(_nsum));
-      _scalars["sigma"]->setValue(sumsq = sqrt((_scalars["sumsquared"]->value() - sum * sum / double(_nsum)) / double(_nsum-1)));
+      _scalars["sigma"]->setValue(sqrt((sumsq - sum * sum / double(_nsum)) / double(_nsum-1)));
       _scalars["rms"]->setValue(sqrt(sumsq/double(_nsum)));
     } else {
       _scalars["sigma"]->setValue(_max - _min);

Comment 2 Netterfield 2006-02-08 05:37:03 UTC

Yes.
cbn

On February 7, 2006 08:33 pm, George Staikos wrote:
[bugs.kde.org quoted mail]

Comment 3 Matthew Truch 2006-02-08 05:40:40 UTC

> correct RMS
> Looks like a refactoring gone wrong...  Ok for 1.2.0 and trunk?
> CCBUG: 121566


I don't know if I'm in the "reviewer's list", but looks good to me.

Comment 4 George Staikos 2006-02-08 05:50:17 UTC

SVN commit 506998 by staikos:

fix RMS computation
BUG: 121566


 M  +2 -2      kstvector.cpp  


--- trunk/extragear/graphics/kst/kst/kstvector.cpp #506997:506998
@@ -195,9 +195,9 @@
 
     if (_nsum >= 2) {
       double sum = _scalars["sum"]->value();
-      double sumsq;
+      double sumsq = _scalars["sumsquared"]->value();
       _scalars["mean"]->setValue(_mean = sum/double(_nsum));
-      _scalars["sigma"]->setValue(sumsq = sqrt((_scalars["sumsquared"]->value() - sum * sum / double(_nsum)) / double(_nsum-1)));
+      _scalars["sigma"]->setValue(sqrt((sumsq - sum * sum / double(_nsum)) / double(_nsum-1)));
       _scalars["rms"]->setValue(sqrt(sumsq/double(_nsum)));
     } else {
       _scalars["sigma"]->setValue(_max - _min);