Defects Index | Documentation Table of Contents
99/05/05 DEFECT IN PROGRAM pages
SYMPTOM: Wildly erroneous tropo estimates were reported when one site's,
gold, was set to be global and therefore passed on in the
normal matrix file. Site ybhb reported a singularity caused
by no date which was not seen if gold's tropo was not stored as
a global parameter.
PROBLEM: Until the end of 1998, the tropo parameters were accessed in
a position (in the matrix) specific manner relative to each other.
At the end of 1998, when pages was generalized to allow most
parameters to be global, this relative referencing no longer held
true and the program was modified to match this situation.
Unfortunately, one routine, pwlswap, which ensures that both
parts of a piece-wise, linear parameter were forward reduced,
still contained a loop which attempted to handle only the
non-global tropo parameters. In this case, because the last
site in the matrix was non-global but another was global, the
tropo's for the last site in the matrix were not being forward
reduced and eliminated properly.
CORRECTION: pwlswap.f: Correct limits for tropo loop.
FOUND BY: Mike Morrison 99/05/05
FIXED BY: Steve Hilla 99/05/05
NOTES: If none or all of the sites were tropos were specified as
global, i.e., typical baseline or orbit processing respectively,
the defective version of the program would have run correctly.
June 25, 1999