[vtkusers] slow data load time (continued), memory mapping

[Kate Kerekes]

Do any vtk classes take advantage of windows memory mapping?  I am having
problems with the time it takes to load a 268 megabyte data set.

kate
----------------------------
Kate,

	What does c++ approach gives you:

#include "vtkImageReader2.h"

int main()
{
   vtkImageReader2 *reader = vtkImageReader2::New();
   reader->SetDataExtent (0, 511, 0, 511, 0, 511 );
   reader->SetDataScalarTypeToShort();
   reader->SetDataByteOrderToLittleEndian();
   reader->SetFilePrefix ("C:\\mouse512\\");
   reader->SetFilePattern ("%s%.4d.slice");
   reader->Update();
   reader->Delete();

   return 0;
}

With a CMakeLists.txt like this:
#
# Find VTK
#
FIND_PACKAGE(VTK)
IF (VTK_FOUND)
   INCLUDE (${VTK_USE_FILE})
ENDIF (VTK_FOUND)
ADD_EXECUTABLE(mouse mouse.cxx)
TARGET_LINK_LIBRARIES (mouse
   vtkIO
)


Thanks
Mathieu

Kate Kerekes wrote:
> I am using the binary version 4.2 (I have not updated to the new 
> release yet).
> 
> kate
> 
> -----Original Message-----
> From: Mathieu Malaterre [mailto:mathieu.malaterre at kitware.com]
> Sent: Monday, September 27, 2004 1:07 PM
> To: Kate Kerekes
> Cc: vtkusers at vtk.org
> Subject: Re: [vtkusers] slow data load time (compared to AMIRA)
> 
> Kate,
> 
> 	How did you compiled VTK ? Could you send us your compilation flags
> (both c and c++) ?
> 
> Thanks
> Mathieu
> 
> Kate Kerekes wrote:
> 
>>Hello All,
>>
>>I am having problems with the time it takes to load a series of slices 
>>of data 512x512, 512 slices of shorts.  For example, loading such a 
>>data set
> 
> in
> 
>>AMIRA software takes 22 seconds, while in my vtk tcl program (using
>>ImageReader2) shown below it takes 55 seconds.
>>
>>I do not think this is due to memory caching.  We have repeated this 
>>experiment on different machines restarting the machines in between
> 
> running
> 
>>the AMIRA load and the vtk load programs.
>>
>>I am running this on my laptop running Windows XP with service pack 2, 
>>AMD athlon 64 chipset 3000+, with 512 megs of memory.
>>
>>Does anyone know why there would be such a performance difference?  Am 
>>I using the right reader?
>>
>>Any help would be appreciated.
>>
>>Thanks,
>>Kate Kerekes
>>
>>#!/bin/sh
>>load vtkCommonTCL.dll
>>load vtkFilteringTCL.dll
>>load vtkGraphicsTCL.dll
>>load vtkIOTCL.dll
>>load vtkImagingTCL.dll
>>load vtkRenderingTCL.dll
>>load vtkHybridTCL.dll
>>source Interactor.tcl
>>source bindings-rw.tcl
>>source bindings-iw.tcl
>>source bindings.tcl
>>source setget.tcl
>>
>>console show
>>set time1 [clock clicks -milliseconds]
>>vtkImageReader2 reader
>>[reader GetOutput] ReleaseDataFlagOn
>>	reader SetDataExtent 0 511 0 511 0 511 
>>	reader SetDataScalarTypeToShort
>>	reader SetDataByteOrderToLittleEndian
>>	reader SetFilePrefix "C:\\mouse512\\"
>>	reader SetFilePattern "%s%.4d.slice"
>>
>>reader Update
>>set time2 [clock clicks -milliseconds]
>>puts "time=[expr ($time2*1.0-$time1*1.0)/1000] seconds"
>>
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