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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

911.0. "Want to know error in arcseconds" by CSC32::S_JOHNSON () Thu Jul 28 1988 16:01

    I have a customer who is using some FORTRAN intrinsic math functions
    which use the same algorithms as the RTL math routines.  He wants
    to know what the biggest error in arcseconds are when he calls atan2d
    or datan2d.  Does anyone know how to figure out what it is?
    
    Thanks in advance for any input.
    
    Scott Johnson  (217328)
    LST
    CSC CX03

                            
T.RTitleUserPersonal
Name
DateLines
911.1AITG::DERAMODaniel V. {AITG,ZFC}:: D'EramoThu Nov 17 1988 19:256
     Is there documentation on the math library that would answer
     this?  Maybe someone in the TLE::FORTRAN conference would
     have an answer.  (The conferences on node TLE are all
     scheduled to be moved to a new node soon).
     
     Dan
911.2CLT::GILBERTMultiple inheritence happensFri Nov 18 1988 09:249
                                <<< CLT::RTL >>>
================================================================================
Note 386.6         Want error in arcseconds for math functions            6 of 7
CLT::GILBERT                                          5 lines  10-AUG-1988 19:05
--------------------------------------------------------------------------------
    The maximum absolute errors are about:

	7.62939E-06 degrees for atan2d  (2.11928E-09 arcseconds)
	1.77636E-15 degrees for datan2d (4.93432E-19 arcseconds)
911.3An oops there.ERLTC::COOPERTopher CooperMon Nov 21 1988 12:206
RE: .2
    
    Looks to me like someone divided by 3600 when they should have
    multiplied.
    
    					Topher