[gdal-dev] Issue with gdalchksum on Fedora 21 ppc64le?
Gawade P
gawade.oefp at gmail.com
Mon Aug 24 01:58:49 PDT 2015
Thanks, Even!
This change solved the issue I was seeing. Appreciate your help on this!
On Mon, Aug 24, 2015 at 1:18 PM, Even Rouault
<even.rouault at spatialys.com> wrote:
> Hi,
>
> Looking at the first difference, 371 - 115 = 256. Those gaps of +256 appear each
> time a value at col n+1 is lesser than the value at col n (when looking the
> reference x86 data). Knowing that HF2 data is delta encoded and that for this
> row the delta between consecutive values is in the [-128,127] range, so
> elligible for 1 byte delta encoding, I think I've found the issue. Apparently
> (according to https://ajax.fedorapeople.org/is-char-signed-or-not.txt), "char"
> on ppc (and other platforms) is "unsigned char", whereas it is "signed char"
> on x86...
>
> Could you try changing line 201 from :
> nVal += ((char*)pabyData)[i-1];
> to
> nVal += ((signed char*)pabyData)[i-1];
>
>
> For clarity, on the encoding side, lines 963 and 1032 that have
> char chDiff = (char)nDiff;
> should be changed to
> signed char chDiff = (signed char)nDiff;
> Although in that case, it apparently doesn't make difference on the end result.
>
> I wouldn't be surprised that similar issues would appear elsewhere in the code
> base.
>
> Even
>
> Le lundi 24 août 2015 05:16:50, vous avez écrit :
>> Thanks a lot for you response Even
>> out.asc is clearly different on the two platforms (x86 and ppc64le).
>>
>> On x86 the content is as follows:
>> ncols 20
>> nrows 20
>> xllcorner 440720.000000000000
>> yllcorner 3750120.000000000000
>> cellsize 60.000000000000
>> 107 123 132 115 132 132 140 132 132 132 107 132 107 132 132 107 123 115
>> 156 148 115 132 107 123 148 115 165 115 140 107 123 123 99 132 123 132 132
>> 132 99 156 115 132 140 132 123 115 140 107 140 115 132 123 107 132 132 115
>> 115 107 115 107 148 132 123 123 115 132 132 123 115 123 115 123 107 115
>> 148 107 115 140 115 132 132 156 132 140 132 132 115 115 115 123 148 123
>> 165 123 132 107 107 132 156 123 189 173 173 148 148 115 148 123 107 132
>> 115 132 156 99 123 115 132 132 206 107 197 173 148 140 140 132 99 132 123
>> 115 140 132 132 99 132 123 132 173 123 115 148 123 148 115 148 123 140 123
>> 107 115 132 115 107 115 99 123 99 181 99 107 123 115 132 115 123 132 115
>> 132 132 123 123 132 99 115 99 123 132 115 115 107 140 140 99 140 99 115
>> 123 107 132 107 115 107 115 123 132 123 107 123 132 132 132 132 132 123 99
>> 132 123 107 148 99 115 123 140 173 123 107 123 123 123 107 123 123 123 107
>> 140 123 123 115 115 90 107 173 107 107 107 107 99 132 123 115 173 148 99
>> 123 123 107 123 99 107 189 173 107 115 115 107 99 140 107 173 140 148 132
>> 132 107 123 99 99 115 99 132 99 140 115 148 123 99 132 123 148 140 140 107
>> 140 90 107 115 107 90 99 123 115 115 115 123 123 148 115 148 99 132 165
>> 148 156 123 107 107 107 115 140 99 115 99 99 107 115 132 115 90 123 115
>> 189 173 140 140 165 115 132 90 99 115 90 99 99 107 99 132 99 107 132 132
>> 156 181 140 173 123 132 99 115 123 74 115 99 123 140 156 132 165 140 140
>> 99 173 247 255 206 132 107 140 123 148 132 165 165 148 140 132 123 107 123
>> 107 123 181 181 156 148 156 156 156 181 132 148 115 132 107 107 107 107
>> 107 115 99 107
>>
>> On ppc64le:
>> ncols 20
>> nrows 20
>> xllcorner 440720.000000000000
>> yllcorner 3750120.000000000000
>> cellsize 60.000000000000
>> 107 123 132 371 388 388 396 644 644 644 875 900 1131 1156 1156 1387
>> 1403 1651 1692 1940
>> 115 132 363 379 404 627 677 883 908 1131 1147 1147 1379 1412 1659
>> 1668 1668 1668 1891 1948
>> 115 132 140 388 635 883 908 1131 1164 1395 1412 1659 1899 1924 1924
>> 2163 2163 2411 2419 2667
>> 148 388 635 635 883 900 900 1147 1395 1403 1651 1659 1899 1907 1940
>> 2155 2163 2188 2419 2436
>> 132 156 388 396 644 644 883 883 883 891 916 1147 1189 1403 1412 1643
>> 1643 1668 1692 1915
>> 189 429 429 660 660 883 916 1147 1387 1412 1651 1668 1692 1891 1915
>> 2163 2180 2180 2254 2411
>> 197 429 660 908 908 1156 1379 1412 1659 1907 1932 2180 2180 2403 2436
>> 2683 2692 2733 2939 3187
>> 148 379 404 627 660 891 908 1147 1387 1395 1412 1651 1899 1907 2147
>> 2171 2403 2485 2659 2667
>> 123 371 388 627 635 644 883 900 900 1147 1147 1156 1379 1395 1635
>> 1659 1668 1907 1907 2155
>> 140 140 355 396 611 627 635 875 900 1131 1139 1387 1395 1403 1412
>> 1659 1899 1915 1924 1924
>> 132 132 132 379 611 644 891 1131 1172 1379 1395 1403 1420 1453 1659
>> 1899 1915 1915 1915 2155
>> 123 123 123 363 396 635 635 883 883 1114 1131 1197 1387 1387 1387
>> 1387 1635 1668 1915 2163
>> 173 404 611 635 635 875 891 1123 1131 1213 1453 1643 1651 1651 1899
>> 2147 2188 2411 2477 2700
>> 148 388 388 619 635 867 867 883 1123 1156 1379 1420 1651 1684 1915
>> 2147 2180 2427 2452 2700
>> 140 363 396 602 619 627 875 1114 1123 1147 1395 1395 1395 1403 1403
>> 1428 1651 1684 1891 1924
>> 165 404 412 635 875 875 875 883 908 1123 1139 1379 1379 1387 1395
>> 1412 1651 1882 1915 2163
>> 189 429 652 652 677 883 900 1114 1123 1139 1370 1379 1379 1387 1635
>> 1668 1891 1899 1924 1924
>> 156 181 396 429 635 644 867 883 891 1098 1139 1379 1403 1420 1436
>> 1668 1701 1932 1932 2147
>> 173 247 255 462 644 875 908 1147 1172 1412 1445 1445 1684 1932 2180
>> 2427 2667 2683 2923 2939
>> 181 181 412 660 668 668 668 693 900 916 1139 1156 1387 1387 1387 1387
>> 1387 1395 1635 1643
>>
>> I will try to dig into this more. Thanks!
>>
>> On Sat, Aug 22, 2015 at 1:57 AM, Even Rouault
>>
>> <even.rouault at spatialys.com> wrote:
>> > Le vendredi 21 août 2015 07:01:41, Gawade P a écrit :
>> >> Hi All,
>> >>
>> >> I am performing the following operation on a Fedora 21 ppc64le machine:
>> >>
>> >> gdal_translate -of HF2 byte.tif byte.tif.tst
>> >>
>> >> Here byte.tiff is TIFF image data
>> >> [root at pts0433-vm12 test]# file byte.tif
>> >> byte.tif: TIFF image data, little-endian, direntries=15, height=20,
>> >> bps=8, compression=none, PhotometricIntepretation=BlackIsZero,
>> >> width=20
>> >>
>> >> The operation completes without issues.
>> >>
>> >> However,
>> >> gdalchksum.py byte.tif
>> >>
>> >> gives me 4672
>> >>
>> >> and
>> >> gdalchksum.py byte.tif.tst
>> >> give me 4716
>> >>
>> >> I have installed gdal and gdal-python using the following rpm packages:
>> >> gdal-1.11.2-4.fc21.ppc64le.rpm
>> >> gdal-python-1.11.2-4.fc21.ppc64le.rpm
>> >>
>> >> The above commands give the same output on Intel (x86) platform i.e.
>> >> 4672. Also, if I transfer the output file byte.tif.tst to an x86
>> >> machine, I get the correct output, i.e. 4672.
>> >>
>> >> Can anyone please guide me on what is the expected output
>> >
>> > In theory this should be 4672 on all platforms. The behaviour you get
>> > would mean that the writing side is OK on PPC64LE, but the reading side
>> > is not.
>> >
>> > The issue is probably in HF2RasterBand::IReadBlock() in
>> > frmts/hf2/hf2dataset.cpp if you want to give a try to debug it.
>> >
>> > A quick way of having an overview of the differences would be to run the
>> > following on x86 and PPC64LE and compare out.asc:
>> >
>> > gdal_translate byte.tif.tst out.asc -of aaigrid
>> >
>> >> Thanks in advance!
>> >> _______________________________________________
>> >> gdal-dev mailing list
>> >> gdal-dev at lists.osgeo.org
>> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>> >
>> > --
>> > Spatialys - Geospatial professional services
>> > http://www.spatialys.com
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
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