MathGroup Archive 2001

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Sun<-> PC

  • To: mathgroup at
  • Subject: [mg29540] Sun<-> PC
  • From: bernd at (Bernd Brandt)
  • Date: Sat, 23 Jun 2001 01:47:29 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

Dear group,

We have Mathematica  4.0.2 for PC and SUN Solaris.
During a minimization procedure of a numerical function defined by
NDSolve the behavior is different:
The PC (Pentium 500 Mhz) just returns a found minimum, the SUN 
(Ultra 10) produced a warning coming from NDSolve:

NDSolve::"ndsz": "At t == 11.465276734029507, step size is 
effectively zero; singularity suspected."

and then from the interpolation:

InterpolatingFunction::"dmval": "Input value 11.989 lies outside the 
range of data in the interpolating function. Extrapolation will be used.

The returned minimum on the SUN is smaller (0.03668 vs 0.03757), these
values  may not be compared because of the NDSolve errors.

We recentely have upgraded to 4.1. The FindMinimum in this  version is
not able to converge within the used nr of 50 iterations, and also show
these platform dependent 'errors'.

This also means that Numerical Integration on a Intel / AMD/ SUN
processors yield different outcomes (when values become very small
probably) and are dependent on the systems FPU units.

Has anyone come accross these platform dependent differences ?


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