[gdal-dev] Issue with gdalchksum on Fedora 21 ppc64le?
Even Rouault
even.rouault at spatialys.com
Mon Aug 24 02:02:09 PDT 2015
Le lundi 24 août 2015 10:58:49, Gawade P a écrit :
> Thanks, Even!
> This change solved the issue I was seeing. Appreciate your help on this!
Great. Could you please file a ticket about that on
https://trac.osgeo.org/gdal/newticket ?
>
> 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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