Updates for SOFA Release 16 : 2020 July 21
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Summary of Changes
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The changes fall into the following categories:
1. Correction of a sign in routine P06E.
2. Correction in the ANSI C macro function dnint in the include file
sofam.h, to improve rounding.
3. Improvements in precision and rounding (see 2 and 3 below).
4. Miscellaneous typographical corrections and improvements to
various other documents.
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FORTRAN 77 Library
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1. iau_P06E Correction. The series are taken from Table 1 of
Hilton, J. et al., 2006, Celest. Mech. Dyn. Astron.
94, 351., and it has been discovered that the one
for general precession, p_A, had the wrong sign for
the t^5 coefficient. The error in the paper has
been corrected in the SOFA code. The correct value
is -0.0000000383 arcsec. (Even after five centuries
the error would be lower than 250 microarcsec.)
2. iau_PB06 Improvements in the method of decomposing the rotation
matrix by ensuring that angles near zero are preferred.
3. iau_JD2CAL Improvements by ensuring precision is not lost when
iau_JDCALF splitting date and time.
4. iau_DAT Release year updated.
5. t_sofa_f.for Updated due to the correction in iau_P06E.
6. iau_FK524 Minor corrections/improvements to the documentation.
iau_FW2M
iau_GMST82
iau_TRXP
iau_XYS00A
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ANSI C Library
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1. iauP06e Correction. The series are taken from Table 1 of
Hilton, J. et al., 2006, Celest. Mech. Dyn. Astron.
94, 351., and it has been discovered that the one
for general precession, p_A, had the wrong sign for
the t^5 coefficient. The error in the paper has
been corrected in the SOFA code. The correct value
is -0.0000000383 arcsec. (Even after five centuries
the error would be lower than 250 microarcsec.)
2. sofam.h Correction to dnint(A).
The existing dnint macro could incorrectly round
numbers just over -0.5 and just under +0.5 due to
the loss of precision when calculating ceil(A-0.5)
or floor(A+0.5). A preliminary test for |A|<0.5
has been added to ensure that such numbers always
round to zero. As none of the SOFA C functions
depend critically on perfect rounding, the change
is unlikely to affect user applications noticeably,
though critical round-trip tests may see an
improvement.
3. iauPb06 Improvements in the method of decomposing the rotation
matrix by ensuring that angles near zero are preferred.
4. iauJd2cal Improvements by ensuring precision is not lost when
iauJdcalf splitting date and time.
5. iauDat Release year updated.
6. t_sofa_c.c Updated due to the correction in iauP06e.
7. iauA2af Minor corrections/improvements to the documentation.
iauA2tf
iauD2tf
iauFk524
iauFw2m
iauGmst82
iauTrxp
iauXys00a
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+ SOFA thanks all those who have reported the various issues that go
+ to ensuring the libraries and documentation are kept up-to-date and
+ relevant.
+
+ End of updates
+ 2020 June 22
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