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Diffstat (limited to 'src/slalib/dr2af.f')
-rw-r--r-- | src/slalib/dr2af.f | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/slalib/dr2af.f b/src/slalib/dr2af.f new file mode 100644 index 0000000..3f9dbf3 --- /dev/null +++ b/src/slalib/dr2af.f @@ -0,0 +1,58 @@ + SUBROUTINE sla_DR2AF (NDP, ANGLE, SIGN, IDMSF) +*+ +* - - - - - - +* D R 2 A F +* - - - - - - +* +* Convert an angle in radians to degrees, arcminutes, arcseconds +* (double precision) +* +* Given: +* NDP i number of decimal places of arcseconds +* ANGLE d angle in radians +* +* Returned: +* SIGN c '+' or '-' +* IDMSF i(4) degrees, arcminutes, arcseconds, fraction +* +* Notes: +* +* 1) NDP less than zero is interpreted as zero. +* +* 2) The largest useful value for NDP is determined by the size +* of ANGLE, the format of DOUBLE PRECISION floating-point +* numbers on the target machine, and the risk of overflowing +* IDMSF(4). For example, on the VAX, for ANGLE up to 2pi, the +* available floating-point precision corresponds roughly to +* NDP=12. However, the practical limit is NDP=9, set by the +* capacity of the 32-bit integer IDMSF(4). +* +* 3) The absolute value of ANGLE may exceed 2pi. In cases where it +* does not, it is up to the caller to test for and handle the +* case where ANGLE is very nearly 2pi and rounds up to 360 deg, +* by testing for IDMSF(1)=360 and setting IDMSF(1-4) to zero. +* +* Called: sla_DD2TF +* +* P.T.Wallace Starlink 19 March 1999 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + INTEGER NDP + DOUBLE PRECISION ANGLE + CHARACTER SIGN*(*) + INTEGER IDMSF(4) + +* Hours to degrees * radians to turns + DOUBLE PRECISION F + PARAMETER (F=15D0/6.283185307179586476925287D0) + + + +* Scale then use days to h,m,s routine + CALL sla_DD2TF(NDP,ANGLE*F,SIGN,IDMSF) + + END |