this bug's URL: http://intevation.de/rt/webrt?serial_num=823
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Subject: rast problems dealing with null maps on DEC Alpha (Linux)
Platform: Linux/Alpha64
Linux distro: Debian
linux cpu: Alpha
Xwindows version: XFree 4.1.0
Xwindows manager: KDE 2.x
TclTk version: tcl/tk 8.3
grass downloaded at: Baylor site
grass binary for platform: I compiled the sources myself
grass sources source: no, I got a source code package from the server,
5.0.0pre2
c compiler name: gcc
Anything to do with floating point raster maps with null map on a DEC Alpha
causes a
floating point exception... FIX taken from source of Grass 4.2.1 with FP +
NULL patches is to not use NaN to mark nulls in floating point maps but
rather to use FLT_MAX...
I could probably make a patch available if required... but if is #if 0
marked on code I am using here...
-------------------------------------------- Managed by Request Tracker
Request Tracker wrote:
Subject: rast problems dealing with null maps on DEC Alpha (Linux)
Anything to do with floating point raster maps with null map on a DEC Alpha
causes a
floating point exception... FIX taken from source of Grass 4.2.1 with FP +
NULL patches is to not use NaN to mark nulls in floating point maps but
rather to use FLT_MAX...
That isn't a fix, but a workaround.
Do you have any idea what causes the FP exception? Or is it any
attempt to perform FP operations on NaN values?
--
Glynn Clements <glynn.clements@virgin.net>
Request Tracker wrote:
this bug's URL: http://intevation.de/rt/webrt?serial_num=823
-------------------------------------------------------------------------
Subject: rast problems dealing with null maps on DEC Alpha (Linux)
Platform: Linux/Alpha64
Linux distro: Debian
linux cpu: Alpha
Xwindows version: XFree 4.1.0
Xwindows manager: KDE 2.x
TclTk version: tcl/tk 8.3
grass downloaded at: Baylor site
grass binary for platform: I compiled the sources myself
grass sources source: no, I got a source code package from the server,
5.0.0pre2
c compiler name: gcc
Anything to do with floating point raster maps with null map on a DEC Alpha
causes a
floating point exception... FIX taken from source of Grass 4.2.1 with FP +
NULL patches is to not use NaN to mark nulls in floating point maps but
rather to use FLT_MAX...
Can you try compiling with the "-mieee" switch, e.g.
CFLAGS=-mieee ./configure ...
The "gcc" Info file suggests that the Alpha's floating-point support
takes some shortcuts, which result in NaN and infinity not working:
`-mieee'
The Alpha architecture implements floating-point hardware
optimized for maximum performance. It is mostly compliant with
the IEEE floating point standard. However, for full compliance,
software assistance is required. This option generates code fully
IEEE compliant code _except_ that the INEXACT FLAG is not
maintained (see below). If this option is turned on, the CPP
macro `_IEEE_FP' is defined during compilation. The option is a
shorthand for: `-D_IEEE_FP -mfp-trap-mode=su -mtrap-precision=i
-mieee-conformant'. The resulting code is less efficient but is
able to correctly support denormalized numbers and exceptional
IEEE values such as not-a-number and plus/minus infinity. Other
Alpha compilers call this option `-ieee_with_no_inexact'.
--
Glynn Clements <glynn.clements@virgin.net>