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TIFF and LibTiff Mail List Archive

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2003.09.05 18:14 "[Tiff] read in whole tiff file", by Pushkar Pradhan
2003.09.10 02:25 "[Tiff] read in whole tiff file", by Pushkar Pradhan
2003.09.10 07:03 "[Tiff] read in whole tiff file", by Andrey Kiselev
2003.09.10 13:04 "[Tiff] read in whole tiff file", by Frank Warmerdam
2003.09.10 13:20 "[Tiff] read in whole tiff file", by Tom Kacvinsky
2003.09.10 17:51 "[Tiff] read in whole tiff file", by Pushkar Pradhan
2003.09.10 18:36 "[Tiff] read in whole tiff file", by Phillip Crews

2003.09.10 17:51 "[Tiff] read in whole tiff file", by Pushkar Pradhan

This is exactly what I wish to do: parallelize the RGB TO LHS transform. Some researchers suggested me to read in the whole image before distributing tiles/strips to different processors to achieve linear speedup. Maybe reading in the image in one call (TIFFClientOpen?) can save I/O overhead instead of multiple calls to TIFFReadTile etc.

BTW I can't find any manual entry for TIFFClientOpen?

Thanks all who replied.

-----Original Message-----

From: Tom Kacvinsky [mailto:tjk@ams.org]
Sent: Wednesday, September 10, 2003 8:20 AM
To: Frank Warmerdam
Cc: Pushkar Pradhan; tiff@remotesensing.org
Subject: Re: [Tiff] read in whole tiff file

I beleive Pushkar is trying to chunk the image up into pieces for processing on different processors. Perhaps the way to chunk the file up is to use either the tiles or strips. Say there are 5 strips and 2 processors. Then 2 strips go to each processor, and the remaining strip goes to one processor or the other... Ditto for tiles. I remember using MPI to parallelize the LDU decomposition of a matrix. It got to be rather heinous, but I was a math magor, not a comp. sci. magor. :-)

Tp,

Is there a way to read in the complete TIFF file in one READ call? I need to do this. Thanks,

I find it almost impossible to imagine a compelling need to read an entire TIFF file in one call. Computer programming languages include looping constructs in order to allow us to complete an aggregate result by a series of small operations, and subroutines so we can bundle them into packages as needed.

However, the TIFFReadRGBAImage() call will read a whole open TIFF image into a memory array in RGBA (red/green/blue/alpha) form in a single call. Try reading over the man page on it and see if it is suitable to your needs.

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