help - s.surf.tps "segmentation fault" error

[Tim Martin; FSO; Soil Sciences]

I am getting segmentation faults (core dumped) under some conditions,
running s.surf.tps, but not under others.  In general, if I
use the default settings for tension, and npmin < 200, things run ok.
But my map ends up with effects between "segments", and 
with "overshoots" due to extreme topography.  From the manual,
I gather I should then increase both tension and npmin. But if I
increase the tension, or use npmin > 200 (not thoroughly
tested) I get a crash, immediately after the map has been "read",
just before the any "percent done" value shows up.

Computer: RS6000 model 340.

Grass:    4.0 with (I think) all the updates.

Map:      -digitized using v.digit, topography of a province in
           Thailand, with extreme topography changes: flat valleys 
           between very steep mountains.
          -converted to a site list, using v.out.point | s.in.ascii
          -about 240,000 points.
          -testing s.surf.tps on smaller regions of 2000 - 5000 points.

Results:
 set segmax=35 npmin=200, others default:       runs ok, poor surface
 set segmax=35 npmin=250 tension=80:            crash
 set segmax=25 npmin=200 tension=80:            crash
 set segmax=35 npmin=300, others default:       crash
 set segmax=35 npmin=250, others default:       crash

where each crash is a "segmentation fault (core dumped)", when the
"percent done:" message shows up, but no percent is done yet.

Can anyone help?

Tim.

 -------------------------------------------------------------
  Tim Martin                   *
  Spatial Information Systems  *   These opinions are my own:
  University of Alberta        *      My employer has none!
  martin at cs.ualberta.ca        *
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