set_location followed by get_location does not necessarily return the same value #621
Description
This was a Jira issue DART-12
see example program below:
program bitwise_creep
use types_mod, only : r8
use location_mod, only : location_type, VERTISLEVEL, set_location, get_location
use utilities_mod, only : initialize_utilities
implicit none
real(r8) :: lon, lat, lev
real(r8) :: lon_lat_lev(3)
type(location_type) :: location
integer :: i
call initialize_utilities()
lon = -91.868560791015625_r8
lat = 16.901844024658203_r8
lev = 1.0_r8
! dart expects longitude [0,360]
do while (lon < 0.0_r8)
lon = lon + 360.0_r8
end do
do while (lon > 360.0_r8)
lon = lon - 360.0_r8
end do
do i = 1, 10
print*, 'lon, lat', lon, lat
location = set_location(lon, lat, lev, VERTISLEVEL)
lon_lat_lev = get_location(location)
print*, 'lon, lat', lon_lat_lev(1), lon_lat_lev(2)
enddo
end program bitwise_creep
hkershaw@cisl-fisher work (main) $ ./bitwise-creep
--------------------------------------
Starting ... at YYYY MM DD HH MM SS =
2024 1 12 10 9 1
--------------------------------------
set_nml_output Echo NML values to log file only
lon, lat 268.13143920898438 16.901844024658203
location_mod: using code with optimized cutoffs
location_mod: Including vertical separation when computing distances:
location_mod: # pascals ~ 1 horiz radian: 6666666.70000
location_mod: # meters ~ 1 horiz radian: 5000000.00000
location_mod: # model levels ~ 1 horiz radian: 2666.70000
location_mod: # scale heights ~ 1 horiz radian: 10.00000
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203
lon, lat 268.13143920898438 16.901844024658203
lon, lat 268.13143920898443 16.901844024658203