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Bug 557977

Summary:	dlamch is miscompiled
Product:	Red Hat Enterprise Linux 5	Reporter:	Susi Lehtola <susi.lehtola>
Component:	lapack	Assignee:	Frantisek Kluknavsky <fkluknav>
Status:	CLOSED NEXTRELEASE	QA Contact:	BaseOS QE - Apps <qe-baseos-apps>
Severity:	medium	Docs Contact:
Priority:	low
Version:	5.4	CC:	alex, ovasik, rvokal
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-03-11 14:14:51 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Susi Lehtola 2010-01-22 22:52:31 UTC

My compilation of Octave 3.2.3 in EPEL 5 at
 http://koji.fedoraproject.org/koji/buildinfo?buildID=152477
fails on i386 with

make[2]: Entering directory `/builddir/build/BUILD/octave-3.2.3/test'
./build_sparse_tests.sh
../run-octave --norc --silent --no-history ./fntests.m .
fatal: lo_ieee_init: floating point format is not IEEE!  Maybe DLAMCH is miscompiled, or you are using some strange system without IEEE floating point math?

The same bug was encountered on Fedora 12
 https://bugzilla.redhat.com/show_bug.cgi?id=510841#c35
and the problem was revealed to be a wrong compilation flag used for dlamch
 https://bugzilla.redhat.com/show_bug.cgi?id=520518#c0
which I suspect is behind the problems on RHEL 5, too.

Comment 1 Susi Lehtola 2010-01-24 12:27:28 UTC

I have verified that this is the case:

$ gfortran -o dlamchtst dlamchtst.f -llapack
$ ./dlamchtst 
  Epsilon                      =   2.220446049250313E-016
  Safe minimum                 =   2.225073858507201E-308
  Base                         =    2.00000000000000     
  Precision                    =   4.440892098500626E-016
  Number of digits in mantissa =    53.0000000000000     
  Rounding mode                =    0.00000000000000     
  Minimum exponent             =   -1021.00000000000     
  Underflow threshold          =   2.225073858507201E-308
  Largest exponent             =    1024.00000000000     
  Overflow threshold           =   1.797693134862316E+308
  Reciprocal of safe minimum   =   4.494232837155790E+307

according to bug #520518, the result should be

 Epsilon                      =   1.11022302462515654E-016
  Safe minimum                 =   2.22507385850720138E-308
  Base                         =    2.0000000000000000     
  Precision                    =   2.22044604925031308E-016
  Number of digits in mantissa =    53.000000000000000     
  Rounding mode                =    1.0000000000000000     
  Minimum exponent             =   -1021.0000000000000     
  Underflow threshold          =   2.22507385850720138E-308
  Largest exponent             =    1024.0000000000000     
  Overflow threshold           =   1.79769313486231571E+308
  Reciprocal of safe minimum   =   4.49423283715578977E+307

Comment 2 Susi Lehtola 2010-04-19 16:23:07 UTC

ping?

Comment 3 Ondrej Vasik 2010-04-20 05:29:55 UTC

If you really want this fixed anytime soon, please contact www.redhat.com/support to raise priority of this issue. Bugzilla is just bug tracker (for the case of RHEL bugs), package bugfix updates are scheduled based on support requests.

Comment 10 Frantisek Kluknavsky 2013-03-11 14:14:51 UTC

I am sorry, but it is now too late in the RHEL-5 release cycle.
RHEL-5.10 (the next RHEL-5 minor release) is going to be the first
production phase 2 [1] release of RHEL-5. Since phase 2 we'll be
addressing only security and critical issues.
This issue will be fixed in RHEL-7 therefore I am closing the bug as
NEXTRELEASE.