[gdal-dev] Re: Performance improvment for gdal_retile

[christian.mueller at nvoe.at]

Ah, things get complicated :-(. I am working on openSUSE 11.3, 32 Bit  
and Ubuntu 10.10 64 Bit. Additionally, I have SUSE Linux Enterprise on  
IBM pSeries and IBM zSeries (Mainframe). Some times I even use gdal on  
AIX.

I compile against gdal 1.7, no debug mode.

The important fact is that your builds work.

What about checking the check sum against a list of possible values ?

I have developed some test cases for my own and thought about  
integrating them into test_gdal_retile.py.  Unfortunately this is not  
be possible if I use checksums because I cannot produce the correct  
numbers.

For the moment, we can leave it as it is.

Christian



Quoting Even Rouault <even.rouault at mines-paris.org>:

> Le samedi 18 décembre 2010 14:31:21, christian.mueller at nvoe.at a écrit :
>> Some last comment about the test case, the current source checks
>>
>> test_gdal_retile_2()
>>
>> ds.GetRasterBand(4).Checksum() != 35
>> ds.GetRasterBand(4).Checksum() != 35
>>
>> If I run this on a Linux Intel 32 bit configuration, it has to be
>>
>> ds.GetRasterBand(4).Checksum() != 283
>> ds.GetRasterBand(4).Checksum() != 122
>>
>> Doing the same on a Linux AMD 64 Bit configuration, the values should be
>>
>> ds.GetRasterBand(4).Checksum() != 283
>> ds.GetRasterBand(4).Checksum() != 126
>>
>> It seems that the cecksum is dependent on the  platform. Is this
>> desirable ? Could this cause some headaches later ?
>
> Yes, this is a bit annoying.
>
> I guess this is related to some compiler difference that impacts numerical
> precision with the bilinear resampling. What is your OS and compiler versions
> ? Do you compile in debug or optimized mode ? Do you use your script against
> GDAL trunk, or do you use it against GDAL 1.7 ?
>
> 35 works for me on Ubuntu 10.04 64bits, and it also works on all Windows
> builds of Tamas (http://vbkto.dyndns.org/sdk/) that test 7 combinations of
> 32/64 bit and MSVC 1310, 1400, 1500 and 1600.
>
>>
>> Cheers
>> Christian
>>
>>
>>
>>
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