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C $Header: /u/u3/gcmpack/MITgcm/pkg/cal/cal_stepsforday.F,v 1.1.20.2 2003/10/07 20:46:37 adcroft Exp $ |
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C $Name: $ |
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|
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#include "CAL_OPTIONS.h" |
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|
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subroutine cal_StepsForDay( |
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I iday, |
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O firststep, |
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O laststep, |
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O nsteps, |
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I mythid |
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& ) |
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|
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c ================================================================== |
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c SUBROUTINE cal_StepsForDay |
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c ================================================================== |
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c |
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c o Given the current day of the integration this routine returns |
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c first, the last and the number of model steps the will have to |
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c be performed. |
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c |
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c This routine also checks consistency of variables quite |
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c extensively. |
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c |
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c started: Christian Eckert eckert@mit.edu 06-Apr-2000 |
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c |
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c changed: |
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c |
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c ================================================================== |
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c SUBROUTINE cal_StepsForDay |
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c ================================================================== |
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|
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implicit none |
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|
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c == global variables == |
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|
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#include "cal.h" |
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|
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c == routine arguments == |
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|
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integer iday |
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integer firststep |
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integer laststep |
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integer nsteps |
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integer mythid |
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|
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c == local variables == |
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|
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integer ierr |
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integer mdstep |
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integer numdays |
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integer numsteps |
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integer frac1 |
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integer frac2 |
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integer frac3 |
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integer frac4 |
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integer fullsteps |
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integer firstyear |
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integer firstmonth |
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integer firstday |
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integer lyfirst |
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integer startsecs |
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integer lastday |
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integer endsecs |
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|
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c == external == |
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|
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external cal_IntDays |
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integer cal_IntDays |
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external cal_IsLeap |
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integer cal_IsLeap |
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|
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c == end of interface == |
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|
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numdays = cal_IntDays( mythid ) |
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lyfirst = cal_IsLeap( firstyear, mythid ) |
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|
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mdstep = int(modelstep) |
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|
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firstyear = modelstartdate(1)/10000 |
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firstmonth = mod(modelstartdate(1)/100,100) |
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firstday = mod(modelstartdate(1),100) |
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lastday = mod(modelenddate(1),100) |
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|
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startsecs = (modelstartdate(2)/10000)*secondsperhour + |
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& mod(modelstartdate(2)/100,100)*secondsperminute + |
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& mod(modelstartdate(2),100) |
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endsecs = (modelenddate(2)/10000)*secondsperhour + |
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& mod(modelenddate(2)/100,100)*secondsperminute + |
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& mod(modelenddate(2),100) |
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|
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if ( numdays .eq. 1 ) then |
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if ( iday .eq. firstday ) then |
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c-- Get the number of steps in the first day. |
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if ( firstday .eq. lastday ) then |
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firststep = 1 |
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laststep = modelintsteps |
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else if ( mod(firstday+1,ndaymonth(firstmonth,lyfirst)) .eq. |
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& lastday ) then |
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c-- This can only happen if we end at midnight of the next day. |
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if ( modelenddate(2) .eq. 0 ) then |
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firststep = 1 |
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laststep = modelintsteps |
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c-- Note: This holds only if modelenddate was determined |
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c-- such that it coincides with the model's final time. |
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else |
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c-- We do not end at midnight of the first day of |
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c-- the next month. |
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ierr = 2604 |
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call cal_PrintError( ierr, mythid ) |
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stop ' stopped in cal_StepsForDay.' |
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endif |
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else |
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c-- The first and the last day are inconsistent with iday. |
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ierr = 2603 |
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call cal_PrintError( ierr, mythid ) |
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stop ' stopped in cal_StepsForDay.' |
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endif |
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else |
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c-- The variables numdays and iday are inconsistent; |
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c-- ( iday .gt. numdays ). |
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ierr = 2602 |
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call cal_PrintError( ierr, mythid ) |
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stop ' stopped in cal_StepsForDay.' |
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endif |
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|
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else if ( numdays .gt. 1 ) then |
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c-- More than one day of integration. |
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if ( iday .eq. 1 ) then |
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firststep = 1 |
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laststep = int((secondsperday - startsecs)/mdstep) |
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else if ( ( iday .gt. 1 ) .and. |
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& ( iday .lt. numdays) ) then |
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c-- Somewhere between first and last month. |
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c-- The first steps in iday. |
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fullsteps = int((secondsperday - startsecs)/mdstep) |
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numsteps = fullsteps |
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c-- What's left in the first day (frac1). |
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frac1 = (secondsperday - startsecs) - fullsteps*mdstep |
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fullsteps = int(secondsperday/modelstep) |
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c-- What's left in a complete day (frac2). |
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frac2 = secondsperday - fullsteps*mdstep |
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c-- What's left up to the current day (frac3). |
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frac3 = frac1 + frac2*(iday - 1) |
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numsteps = numsteps + (iday - 1)*fullsteps + |
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& frac3/mdstep |
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laststep = numsteps |
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firststep = laststep - secondsperday/mdstep + 1 |
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|
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else if ( iday .eq. numdays ) then |
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c-- The last day of integration. |
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c-- The first step in iday. |
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fullsteps = int((secondsperday - startsecs)/mdstep) |
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numsteps = fullsteps |
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c-- What's left in the first day (frac1). |
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frac1 = (secondsperday - startsecs) - fullsteps*mdstep |
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fullsteps = int(secondsperday/modelstep) |
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c-- What's left in a complete day (frac2). |
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frac2 = secondsperday - fullsteps*mdstep |
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c-- What's left up to the day before the last (frac3). |
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frac3 = frac1 + frac2*(iday - 2) |
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numsteps = numsteps + (iday - 2)*fullsteps |
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c-- The last step in iday. |
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if ( modelenddate(2) .eq. 0 ) then |
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c-- This can only happen if we end at midnight of the next day. |
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laststep = numsteps + fullsteps |
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firststep = numsteps + 1 |
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c-- Note: There should be no fraction left |
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c-- ( mod(frac3,mdstep) = frac3/mdstep ) if modelenddate |
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c-- is based on an integral number of timesteps. |
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else |
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frac4 = frac3 + endsecs |
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numsteps = numsteps + frac4/mdstep |
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laststep = numsteps |
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|
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c-- Note: There should be no fraction left |
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c-- ( mod(frac4,mdstep = frac4/mdstep ) if modelenddate |
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c-- is based on an integral number of timesteps. |
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|
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firststep = laststep - endsecs/mdstep + 1 |
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endif |
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else |
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c-- The variables iday and numdays are inconsistent. |
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ierr = 2605 |
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call cal_PrintError( ierr, mythid ) |
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stop ' stopped in cal_DaysForMonth.' |
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endif |
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else |
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c-- The number of days to integrate is wrong; check cal_IntDays. |
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ierr = 2601 |
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call cal_PrintError( ierr, mythid ) |
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stop ' stopped in cal_StepsForDay.' |
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endif |
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|
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c-- The number of days to integrate in the given month. |
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nsteps = laststep - firststep + 1 |
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|
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return |
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end |
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