Re: gammaln(0) (octave-3.3.51+, MinGW)

[Tatsuro MATSUOKA]

Hello

> In gfortran DLGAMA() is intrinsically defined.  
> 
> If it is used, perhaps the error will be disappeared.
> http://gcc.gnu.org/onlinedocs/gfortran/LOG_005fGAMMA.html#LOG_005fGAMMA
> 
> In the case slatec gamma function, we cannot use it at x=0 so that special 
> treatment is
> required, for
> gammaln in octave, I think.
> 
> Am I wrong?

In gcc, lgamma, i.e.log(abs(gamma)) is defined. (also lgammaf) 
I have looked into "config.log" and found
configure:47767: checking for lgamma
<snip>
configure:47767: result: yes
configure:47767: checking for lgammaf
<snip>
configure:47767: result: yes

And in config.h, there exist

/* Define to 1 if you have the `lgamma' function. */
#define HAVE_LGAMMA 1

/* Define to 1 if you have the `lgammaf' function. */
#define HAVE_LGAMMAF 1


Perhaps for gamma() in the octave-3.3.51+ built by me, lgamma is used.  
However, for gammaln() in, subroutine dlgams in slatec is used.

Because I can see in the error message,
 error: lgamma: exception encountered in Fortran subroutine dlgams_

Is there any reason that buid-in lgamma in gcc is not used but the slatec 
dlgams is used, although
'configure' detects it ?

Regards

Tatsuro

--- Tatsuro MATSUOKA  wrote:

> Hello
> 
> > I cannot find source of xstopx in libcruft source files.
> > 
> > However when the code link against libcruft.dll.a, undefined symbol error 
> > messages for
> 'xstopx'
> > were
> > disappeared.
> 
> I found the reason. xstopx is defined in   misc/f77-fcn.h in libcruft.
> 
> > However
> > 
> >       program test
> >       DOUBLE PRECISION X, DLGAM, SGNGAM, DLNGAM
> >       X=0
> >       write(*,*) DGAMMA(X)
> >       end
> > 
> > The above code gives
> > 
> > $ ./test
> >                  +Infinity
> 
> This is reasonable.  In this case, dgamma intrinsic in gfortran  is used.
> If I add 'EXTERNAL DGAMMA', slatac dgamma is used and the same error as that 
> by the dlgams
> subroutime
> is caused.
> 
> In gfortran DLGAMA() is intrinsically defined.  
> 
> If it is used, perhaps the error will be disappeared.
> http://gcc.gnu.org/onlinedocs/gfortran/LOG_005fGAMMA.html#LOG_005fGAMMA
> 
> In the case slatec gamma function, we cannot use it at x=0 so that special 
> treatment is
> required, for
> gammaln in octave, I think.
> 
> Am I wrong?
> 
> Regards
> 
> Tatsuro
> 
> 
> 
> --- Tatsuro MATSUOKA  wrote:
> 
> > Hello
> > 
> > I have reported error in test beta.m.
> > Development source on July 2010 (platform MinGW, GCC-4.5.0)
> > 
> > 
> > http://octave.1599824.n4.nabble.com/error-in-test-beta-m-tc2303186.html#a2303407
> > 
> > This problem reduced to 'gammaln(0)'
> > 
> > octave:5> gammaln(0)
> >  ***MESSAGE FROM ROUTINE DGAMMA IN LIBRARY SLATEC.
> >  ***FATAL ERROR, PROG ABORTED, TRACEBACK REQUESTED
> >  *  X IS 0
> >  *  ERROR NUMBER = 4
> >  *
> >  ***END OF MESSAGE
> > 
> >  ***JOB ABORT DUE TO FATAL ERROR.
> > 0          ERROR MESSAGE SUMMARY
> >  LIBRARY    SUBROUTINE MESSAGE START             NERR     LEVEL     COUNT
> >  SLATEC     DGAMMA     X IS 0                       4         2         2
> > 
> > error: lgamma: exception encountered in Fortran subroutine dlgams_
> > 
> > I can fined symbol 'dlgams'
> > 
> > I have been trying to build simple test file using DLGAMS in slatec-fn like
> > 
> >       program test
> >       DOUBLE PRECISION X, DLGAM, SGNGAM, DLNGAM
> >       X=0
> >       call DLGAMS (X, DLGAM, SGNGAM)
> >       write (*,*) DLGAM, SGNGAM
> >       end
> > 
> > In the slatec-err routines (or other libcruft source files), I found 'call 
> > xstopx('messeage')'
> > but
> > I cannot find source of xstopx in libcruft source files.
> > 
> > However when the code link against libcruft.dll.a, undefined symbol error 
> > messages for
> 'xstopx'
> > were
> > disappeared.
> > 
> > And test result is 
> > 
> > $ gdb test
> > GNU gdb (GDB) 7.0.1
> > Copyright (C) 2009 Free Software Foundation, Inc.
> > License GPLv3+: GNU GPL version 3 or later 
> > <http://gnu.org/licenses/gpl.html>
> > This is free software: you are free to change and redistribute it.
> > There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
> > and "show warranty" for details.
> > This GDB was configured as "mingw32".
> > For bug reporting instructions, please see:
> > <http://www.gnu.org/software/gdb/bugs/>...
> > Reading symbols from 
> > c:\usr\Tatsu\mingwhome\octaves\dgammatest/test.exe...done.
> > (gdb) br test
> > Breakpoint 1 at 0x4013c9: file test.f, line 3.
> > (gdb) run
> > Starting program: c:\usr\Tatsu\mingwhome\octaves\dgammatest/test.exe
> > [New Thread 1048.0x8fc]
> > 
> > Breakpoint 1, test () at test.f:3
> > 3             X=0
> > Current language:  auto
> > The current source language is "auto; currently fortran".
> > (gdb) step
> > 4             call DLGAMS (X, DLGAM, SGNGAM)
> > (gdb) step
> >  ***MESSAGE FROM ROUTINE DGAMMA IN LIBRARY SLATEC.
> >  ***FATAL ERROR, PROG ABORTED, TRACEBACK REQUESTED
> >  *  X IS 0
> >  *  ERROR NUMBER = 4
> >  *
> >  ***END OF MESSAGE
> > 
> >  ***JOB ABORT DUE TO FATAL ERROR.
> > 0          ERROR MESSAGE SUMMARY
> >  LIBRARY    SUBROUTINE MESSAGE START             NERR     LEVEL     COUNT
> >  SLATEC     DGAMMA     X IS 0                       4         2         1
> > 
> > gdb: unknown target exception 0xc0000027 at 0x77be5464
> > 
> > Program received signal ?, Unknown signal.
> > 0x77be5464 in msvcrt!_global_unwind2 () from C:\WINDOWS\system32\msvcrt.dll
> > (gdb) bt
> > #0  0x77be5464 in msvcrt!_global_unwind2 () from 
> > C:\WINDOWS\system32\msvcrt.dll
> > #1  0x77be6d8c in msvcrt!longjmp () from C:\WINDOWS\system32\msvcrt.dll
> > #2  0x00000000 in ?? ()
> > 
> > I have obtained the same error gcc-4.4.0 / MinGW
> > 
> > Unfortunately I did not install gdb on cygwin but I could the following 
> > message in cygwin. 
> > 
> >  ***MESSAGE FROM ROUTINE DGAMMA IN LIBRARY SLATEC.
> >  ***FATAL ERROR, PROG ABORTED, TRACEBACK REQUESTED
> >  *  X IS 0
> >  *  ERROR NUMBER = 4
> >  *
> >  ***END OF MESSAGE
> > 
> >  ***JOB ABORT DUE TO FATAL ERROR.
> > 0          ERROR MESSAGE SUMMARY
> >  LIBRARY    SUBROUTINE MESSAGE START             NERR     LEVEL     COUNT
> >  SLATEC     DGAMMA     X IS 0                       4         2         1
> > 
> > ***********************************
> > 
> > The error message claim that X is 0 in DGAMMA.
> > 
> > However
> > 
> >       program test
> >       DOUBLE PRECISION X, DLGAM, SGNGAM, DLNGAM
> >       X=0
> >       write(*,*) DGAMMA(X)
> >       end
> > 
> > The above code gives
> > 
> > $ ./test
> >                  +Infinity
> > 
> > ???????
> > 
> > Any suggestions?
> > 
> > Regards
> > 
> > Tatsuro
> > 
> > 
> > 
> > 
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> 
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