Has there been a fundamental change in how GRASS displays with commands like
d.rast between 4.3 and 5.0.0 or 5.0.1? I made some comparisons and it is
definitely much slower with newer versions. I displayed 13 grids in succession
as a test
Version Time
------- ----
4.3 pre-compiled 4 sec
5.0.0 pre-compiled 9 seconds
5.0.1 compiled from src 7 seconds
The compiled from src executables were created on a SUN using the SUNWorkshop C
compiler with switches "-fast -xtarget=ultra2 -xarch=v8plusa". Those basically
expand to an optimized version for the hardware and an O3-O5 optimization level.
Should run very fast but that isn't the case.
Thanks,
Wayne
-----------------------
Wayne Gibson
Oregon State University
gibson@coas.oregonstate.edu
(541) 737-5696
Wayne Gibson wrote:
Has there been a fundamental change in how GRASS displays with commands like
d.rast between 4.3 and 5.0.0 or 5.0.1?
Yes; the display system has been substantially re-written.
I made some comparisons and it is definitely much slower with newer
versions. I displayed 13 grids in succession as a test
There are a number of possible reasons why it might run slower; the
most likely ones are:
a) The display library might be using more colours.
b) The monitor (XDRIVER) always draws into a background pixmap rather
than directly onto the screen; this results in more work for the X
server.
If the difference is (primarily) due to a) above, the difference
between 4.3 and 5.0 will be a constant, regardless of the size of the
raster or the size of the monitor window. If it's due to b), enlarging
the monitor window will increase the difference.
There could also be other reasons.
--
Glynn Clements <glynn.clements@virgin.net>