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module conf_dat2d_m |
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|
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! This module is clean: no C preprocessor directive, no include line. |
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! From conf_dat2d.F, version 1.2 2006/01/27 15:14:22 |
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|
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IMPLICIT NONE |
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|
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contains |
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|
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SUBROUTINE conf_dat2d(xd, yd, xf, yf, champd, interbar) |
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|
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! Auteur : P. Le Van |
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|
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! Ce sous-programme configure le champ de données 2D 'champd' et |
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! les longitudes et latitudes de telle façon qu'on ait - pi à pi |
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! en longitude et pi/2 à - pi/2 en latitude. |
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|
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! This procedure receives a 2D field, with the corresponding |
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! coordinate variables: longitude and latitude. |
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! The procedure converts longitude and latitude to radians, if the |
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! input values are in degrees. |
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! If the input longitudes are between 0 and 2 pi, the procedure |
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! computes the congruent longitudes between -pi and pi, and permutes |
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! them so they stay in increasing order. |
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! If the input latitudes are from south pole to north pole, the |
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! procedure permutes them so they become from north to south. |
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! Any change on longitudes or latitudes induces a change on the 2D field. |
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! If required, the longitudes and latitudes are finally replaced |
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! by their mid-values. |
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|
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use nrutil, only: assert_eq |
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use comconst, only: pi |
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|
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REAL, intent(in):: xd(:) |
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! (longitudes, in degrees or radians, in increasing order, from 0° |
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! to 360° or -180° to 180°) |
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|
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REAL, intent(in):: yd(:) |
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! (latitudes, in degrees or radians, in increasing or decreasing |
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! order, from pole to pole) |
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|
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LOGICAL, intent(in), optional:: interbar |
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REAL, intent(out):: xf(:), yf(:) ! longitudes and latitudes, in rad |
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REAL, intent(inout):: champd(:, :) |
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|
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! Variables locales: |
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|
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INTEGER lons, lats |
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LOGICAL radianlon ! "xd" is in degrees |
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logical invlon ! "xd" contains longitudes between 0 and 2 pi |
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logical radianlat ! "yd" is in rad |
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REAL rlatmin, rlatmax, old_xf_1 |
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INTEGER i, j |
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logical mid_values |
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|
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!------------------------------ |
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|
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lons = assert_eq(size(xd), size(xf), size(champd, 1), "conf_dat2d lons") |
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lats = assert_eq(size(yd), size(yf), size(champd, 2), "conf_dat2d lats") |
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|
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IF (xd(1) >= - pi -0.5 .AND. xd(lons) <= pi + 0.5) THEN |
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radianlon = .TRUE. |
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invlon = .FALSE. |
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ELSE IF (xd(1) >= -0.5 .AND. xd(lons) <= 2 * pi+0.5) THEN |
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radianlon = .TRUE. |
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invlon = .TRUE. |
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ELSE IF (xd(1) >= -180.5 .AND. xd(lons) <= 180.5) THEN |
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radianlon = .FALSE. |
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invlon = .FALSE. |
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ELSE IF (xd(1) >= -0.5 .AND. xd(lons) <= 360.5) THEN |
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radianlon = .FALSE. |
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invlon = .TRUE. |
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ELSE |
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stop '"conf_dat2d": problem with longitudes' |
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ENDIF |
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|
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rlatmin = MIN(yd(1), yd(lats)) |
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rlatmax = MAX(yd(1), yd(lats)) |
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|
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IF (rlatmin >= -pi / 2 - 0.5 .AND. rlatmax <= pi / 2 + 0.5)THEN |
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radianlat = .TRUE. |
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ELSE IF (rlatmin >= -90. - 0.5 .AND. rlatmax <= 90. + 0.5) THEN |
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radianlat = .FALSE. |
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ELSE |
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stop '"conf_dat2d": problem with latitudes' |
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ENDIF |
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|
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IF (radianlon) THEN |
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xf(:) = xd(:) |
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else |
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xf(:) = xd(:) * pi / 180. ! convert to rad |
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ENDIF |
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|
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IF (radianlat) THEN |
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yf(:) = yd(:) |
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else |
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yf(:) = yd(:) * pi / 180. ! convert to rad |
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ENDIF |
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|
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IF (invlon) THEN |
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! On tourne les longitudes pour avoir - pi à + pi : |
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|
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! Get the index of the first longitude > pi: |
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i = 1 |
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do while (xf(i) <= pi) |
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i = i + 1 |
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end do |
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|
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xf(i:) = xf(i:) - 2 * pi |
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xf(:) = cshift(xf, shift=i - 1) |
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champd(:, :) = cshift(champd, shift=i - 1) |
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ENDIF |
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|
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IF (yd(1) < yd(lats)) THEN |
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! "yd" contains latitudes from south pole to north pole, |
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! reverse their order in "yf": |
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yf(lats:1:-1) = yf(:) |
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champd(:, lats:1:-1) = champd(:, :) |
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ENDIF |
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|
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if (present(interbar)) then |
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mid_values = interbar |
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else |
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mid_values = .true. ! default |
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end if |
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if (mid_values) then |
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! Replace longitudes and latitudes by their mid-values: |
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old_xf_1 = xf(1) |
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forall (i = 1: lons - 1) xf(i) = 0.5 * (xf(i) + xf(i+1)) |
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xf(lons) = 0.5 * (xf(lons) + old_xf_1 + 2 * pi) |
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|
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forall (j = 1: lats - 1) yf(j) = 0.5 * (yf(j) + yf(j+1)) |
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end if |
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|
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END SUBROUTINE conf_dat2d |
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|
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end module conf_dat2d_m |
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