function [ w, f ] = jed_to_weekday ( jed ) %*****************************************************************************80 % %% JED_TO_WEEKDAY computes the day of the week from a JED. % % Discussion: % % BC 4713/01/01 => JED = 0.0 was noon on a Monday. % % jedmod = mod ( 0.0D+00, 7.0D+00 ) = 0.0D+00 % j = mod ( nint ( 0 ), 7 ) = 0 % f = ( 0.0D+00 + 0.5D+00 ) - real ( j ) = 0.5D+00 % w = i4_wrap ( 0 + 2, 1, 7 ) = 2 = MONDAY % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 28 April 2010 % % Author: % % John Burkardt % % Reference: % % Edward Richards, % Mapping Time, The Calendar and Its History, % Oxford, 1999. % % Parameters: % % Input, real JED, the Julian Ephemeris Date. % % Output, integer W, the day of the week of the date. % The days are numbered from Sunday through Saturday, 1 through 7. % % Output, real F, the fractional part of the day. % jedmod = mod ( jed, 7.0 ); j = mod ( floor ( jedmod ), 7 ); f = ( jedmod + 0.5 ) - j; w = i4_wrap ( j + 2, 1, 7 ); return end