[Insight-developers] Rounding functions in itkMacro.h

Tom Vercauteren tom.vercauteren at m4x.org
Tue May 12 17:26:04 EDT 2009 

Hi Luis,

I think I got the culprit. It didn't make sense to me how
vnl_math_rnd_halfintup could be undeclared. I am using ubuntu 9.04
with gcc 4.3 and every thing works out fine. Se for example this debug
build with sse2 rounding:
http://www.cdash.org/CDash/buildSummary.php?buildid=331407
http://www.cdash.org/CDash/testDetails.php?test=22870870&build=331407

The only possible reason for a mising vnl_math_rnd_halfintup is a
missing or outdated vnl_math.h. Looking back at the code
  http://public.kitware.com/cgi-bin/viewcvs.cgi/Code/Common/itkMacro.h?root=Insight&view=markup
I see that vnl_math.h is only included if ITK_USE_PORTABLE_ROUND is
ON. I wasn't using this variable...

Could you please try and recompile by changing
  #ifndef ITK_USE_PORTABLE_ROUND
  #include "vnl/vnl_math.h"
  #endif
by
  #include "vnl/vnl_math.h"
in
  itkMacro.h
?

Sorry for not giving you a patch but I don't have a development machine at hand.

Also, I saw from your previous email that you had set
VNL_CONFIG_ENABLE_SSE2 to ON. This is not used by the sse2 rounding
functions which only relies on VNL_CONFIG_ENABLE_SSE2_ROUNDING. Since
VXL developers aresaying that VNL_CONFIG_ENABLE_SSE2 is unstable, I
wouldn't recommend turning this option on.

Hope this helps,
Tom


On Tue, May 12, 2009 at 18:14, Luis Ibanez <luis.ibanez at kitware.com> wrote:
> HI Tom,
>
> Thanks for the new patch.
>
> Unfortunately it is not compiling for me.
>
>
> Here is what I got:
>
>
> [ 41%] Building CXX object Code/Common/CMakeFiles/ITKCommon.dir/itkBarrier.o
> In file included from /home/ibanez/src/Insight/Code/Common/itkTimeStamp.h:23,
>                 from /home/ibanez/src/Insight/Code/Common/itkLightObject.h:21,
>                 from /home/ibanez/src/Insight/Code/Common/itkBarrier.h:20,
>                 from /home/ibanez/src/Insight/Code/Common/itkBarrier.cxx:17:
> /home/ibanez/src/Insight/Code/Common/itkMacro.h: In function ‘int
> itk::Math::RoundHalfIntegerUp(float)’:
> /home/ibanez/src/Insight/Code/Common/itkMacro.h:979: error:
> ‘vnl_math_rnd_halfintup’ was not declared in this scope
> /home/ibanez/src/Insight/Code/Common/itkMacro.h: In function ‘int
> itk::Math::RoundHalfIntegerUp(double)’:
> /home/ibanez/src/Insight/Code/Common/itkMacro.h:980: error:
> ‘vnl_math_rnd_halfintup’ was not declared in this scope
> /home/ibanez/src/Insight/Code/Common/itkMacro.h: In function ‘int
> itk::Math::RoundHalfIntegerToEven(float)’:
> /home/ibanez/src/Insight/Code/Common/itkMacro.h:981: error:
> ‘vnl_math_rnd_halfinttoeven’ was not declared in this scope
> /home/ibanez/src/Insight/Code/Common/itkMacro.h: In function ‘int
> itk::Math::RoundHalfIntegerToEven(double)’:
> /home/ibanez/src/Insight/Code/Common/itkMacro.h:982: error:
> ‘vnl_math_rnd_halfinttoeven’ was not declared in this scope
> make[2]: *** [Code/Common/CMakeFiles/ITKCommon.dir/itkBarrier.o] Error 1
> make[1]: *** [Code/Common/CMakeFiles/ITKCommon.dir/all] Error 2
>
>
>
> and the SSE flags in my build are ON
>
>  grep ENABLE_SSE MakeCache.txt
>
> VNL_CONFIG_ENABLE_SSE2:BOOL=ON
> VNL_CONFIG_ENABLE_SSE2_ROUNDING:BOOL=ON
> //Advanced flag for variable: VNL_CONFIG_ENABLE_SSE2
> VNL_CONFIG_ENABLE_SSE2-ADVANCED:INTERNAL=1
> //Modified flag for variable: VNL_CONFIG_ENABLE_SSE2
> VNL_CONFIG_ENABLE_SSE2-MODIFIED:INTERNAL=1
> //Advanced flag for variable: VNL_CONFIG_ENABLE_SSE2_ROUNDING
> VNL_CONFIG_ENABLE_SSE2_ROUNDING-ADVANCED:INTERNAL=1
> //Modified flag for variable: VNL_CONFIG_ENABLE_SSE2_ROUNDING
> VNL_CONFIG_ENABLE_SSE2_ROUNDING-MODIFIED:INTERNAL=1
>
>
> BTW: This is a Debug build in gcc 4.3.2, Linux Ubuntu 8.10.
>
>
>      Luis
>
>
> =========================================
> On Tue, May 12, 2009 at 8:48 AM, Tom Vercauteren
> <tom.vercauteren at m4x.org> wrote:
>> Luis,
>>
>> I have put an updated patch on the bug tracker:
>> http://public.kitware.com/Bug/file_download.php?file_id=2236&type=bug
>>
>> In addition to the changes I mentioned earlier, it includes some small
>> modifications to some CMakeLists.txt in order to ease turning on SSE2
>> rounding.
>>  cmake -DVNL_CONFIG_ENABLE_SSE2_ROUNDING=ON <path_to_itk>
>> and
>>  ccmake <path_to_itk>
>>  switch VNL_CONFIG_ENABLE_SSE2_ROUNDING to on
>> now also works with gcc
>>
>> Let me know if it works for you.
>>
>> Tom
>>
>> On Tue, May 12, 2009 at 12:43, Tom Vercauteren <tom.vercauteren at m4x.org> wrote:
>>> Hi Luis,
>>>
>>> I have almost the same system so this will ease the process.
>>>
>>> The problem is indeed related to the -msse2 flag. Running
>>>  cmake -DCMAKE_C_FLAGS="-msse2" -DCMAKE_CXX_FLAGS="-msse2"
>>> -DVNL_CONFIG_ENABLE_SSE2_ROUNDING=ON <path_to_itk>
>>> works correctly.
>>>
>>> So it looks like the cmake magic used by vxl to detect and add sse2
>>> support is wrong. Actually running
>>>  cmake -DVNL_CONFIG_ENABLE_SSE2_ROUNDING=ON <path_to_itk>
>>> leads to a cmake error.
>>>
>>> This is not specific to the patched itk version as the same behavior
>>> is observed on a pristine checkout of the vxl svn trunk.
>>>
>>> There are at least two errors I can see from the cmake scripts in vxl
>>> svn trunk when VNL_CONFIG_ENABLE_SSE2_ROUNDING is ON.
>>>
>>> 1)  ADD_DEFINITIONS( -msse2 ) is called after vxl tries to detect
>>> whether it has sse2 support. However this flag is required for gcc
>>> (4.3) to find emmintrin.h and use the sse2 intrinsics.
>>>
>>> 2) Even if ADD_DEFINITIONS( -msse2 ) was called prior to
>>>  PERFORM_CHECK_HEADER(emmintrin.h VXL_HAS_EMMINTRIN_H)
>>> and
>>>  PERFORM_CMAKE_TEST_RUN(vxl_platform_tests.cxx VXL_HAS_SSE2_HARDWARE_SUPPORT)
>>> it wouldn't make a difference since PERFORM_CHECK_HEADER and
>>> PERFORM_CMAKE_TEST_RUN do not rely on such ADD_DEFINITIONS.
>>>
>>> I am not sure how to fix this right now as I am not a cmake expert.
>>> Any help would be appreciated.
>>>
>>>
>>> Note this this issue does not affect the case when
>>> VNL_CONFIG_ENABLE_SSE2_ROUNDING is OFF. In such a case, on your
>>> system, the implementation will fallback to the gcc assembly calls,
>>> e.g.
>>>  inline int vnl_math_rnd_halfinttoeven(float  x) { int r; __asm__
>>> __volatile__ ("fistpl %0" : "=m"(r) : "t"(x) : "st"); return r; }
>>>
>>> I'll report back if I find a patch for the cmake scripts that I find reasonable.
>>>
>>> Tom
>>>
>>> On Tue, May 12, 2009 at 04:27, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>>>> Hi Tom,
>>>>
>>>> I'm testing this on a Laptop:
>>>>
>>>>    Linux Ubuntu 8.10
>>>>    gcc 4.3.2
>>>>    Intel(R) Core(TM)2 Duo CPU     T9600  @ 2.80GHz
>>>>
>>>>
>>>> The error was a link error.
>>>> Missing symbols.
>>>>
>>>> lshw returns the following data from the CPU:
>>>>
>>>>  *-cpu
>>>>          description: CPU
>>>>          product: Intel(R) Core(TM)2 Duo CPU     T9600  @ 2.80GHz
>>>>          vendor: Intel Corp.
>>>>          physical id: 400
>>>>          bus info: cpu at 0
>>>>          version: 6.7.6
>>>>          slot: Microprocessor
>>>>          size: 2801MHz
>>>>          capacity: 2801MHz
>>>>          width: 64 bits
>>>>          clock: 266MHz
>>>>          capabilities: fpu fpu_exception wp vme de pse tsc msr pae
>>>> mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr
>>>> sse sse2 ss ht tm pbe nx x86-64 constant_tsc arch_perfmon pebs bts pni
>>>> monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr sse4_1 lahf_lm cpufreq
>>>>          configuration: id=0
>>>>
>>>> --
>>>>
>>>>      Luis
>>>>
>>>>
>>>> ------------------------------
>>>> On Mon, May 11, 2009 at 7:16 PM, Tom Vercauteren
>>>> <tom.vercauteren at m4x.org> wrote:
>>>>> Luis,
>>>>>
>>>>> Can you provide some information on your configuration (OS, compiler,
>>>>> cpu)? Also did you get a compilation error or a link error?
>>>>>
>>>>> One potential thing to look at is whether your machine actually
>>>>> supports sse2 and whether vxl correctly detects it. It looks like I
>>>>> missed a patch to the sse2 detection in the list I gave you:
>>>>> http://vxl.svn.sourceforge.net/viewvc/vxl/trunk/config/cmake/config/CMakeLists.txt?r1=23457&r2=23456&pathrev=23457
>>>>> http://vxl.svn.sourceforge.net/viewvc/vxl/trunk/config/cmake/config/vxl_platform_tests.cxx?r1=23457&r2=23456&pathrev=23457
>>>>>
>>>>> No matter this patch, setting  VNL_CONFIG_ENABLE_SSE2_ROUNDING to OFF
>>>>> should definitely not remove the declarations of the new rounding
>>>>> methods. It should simply fallback to another implementation than the
>>>>> SSE2 one (gcc-specific or msvc-specific or vanilla c).
>>>>>
>>>>> Since I don't have access to my computer right now, it's a bit
>>>>> difficult for me to provide you more information right now.
>>>>>
>>>>> Tom
>>>>>
>>>>> On Tue, May 12, 2009 at 00:44, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>>>>>> Hi Tom,
>>>>>>
>>>>>> Setting  VNL_CONFIG_ENABLE_SSE2_ROUNDING to OFF
>>>>>> removes the declarations of the new rounding methods in
>>>>>> vnl_math.h.
>>>>>>
>>>>>> I'm probably doing something wrong here.
>>>>>>
>>>>>> I have generated a patch with the changes and uploaded it
>>>>>> to the bug tracker:
>>>>>>
>>>>>> You will find it in:
>>>>>>    http://public.kitware.com/Bug/view.php?id=6558
>>>>>>
>>>>>> is the patch named:
>>>>>>
>>>>>>          PortableRound-May-11-2009.patch
>>>>>>
>>>>>>
>>>>>> If you have a chance,
>>>>>> could you help me find out what I'm missing ?
>>>>>>
>>>>>>
>>>>>>      Thanks
>>>>>>
>>>>>>
>>>>>>            Luis
>>>>>>
>>>>
>>>
>>
>

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