| 1 | module principal_cshift_m |
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| 2 | |
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| 3 | IMPLICIT NONE |
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| 4 | |
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| 5 | CONTAINS |
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| 6 | |
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| 7 | SUBROUTINE principal_cshift(is2, xlon, xprimm) |
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| 8 | |
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| 9 | ! Add or subtract 2 pi so that xlon is near [-pi, pi], then cshift |
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| 10 | ! so that xlon is in ascending order. Make the same cshift on |
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| 11 | ! xprimm. |
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| 12 | |
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| 13 | USE lmdz_physical_constants, ONLY: twopi |
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| 14 | USE serre_mod, ONLY: clon |
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| 15 | |
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| 16 | include "dimensions.h" |
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| 17 | ! for iim |
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| 18 | |
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| 19 | INTEGER, INTENT(IN):: is2 |
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| 20 | REAL, INTENT(INOUT):: xlon(:), xprimm(:) ! (iim + 1) |
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| 21 | |
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| 22 | !----------------------------------------------------- |
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| 23 | |
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| 24 | IF (is2 /= 0) THEN |
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| 25 | IF (clon <= 0.) THEN |
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| 26 | IF (is2 /= 1) THEN |
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| 27 | xlon(:is2 - 1) = xlon(:is2 - 1) + twopi |
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| 28 | xlon(:iim) = cshift(xlon(:iim), shift = is2 - 1) |
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| 29 | xprimm(:iim) = cshift(xprimm(:iim), shift = is2 - 1) |
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| 30 | END IF |
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| 31 | else |
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| 32 | xlon(is2 + 1:iim) = xlon(is2 + 1:iim) - twopi |
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| 33 | xlon(:iim) = cshift(xlon(:iim), shift = is2) |
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| 34 | xprimm(:iim) = cshift(xprimm(:iim), shift = is2) |
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| 35 | end IF |
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| 36 | end if |
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| 37 | |
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| 38 | xlon(iim + 1) = xlon(1) + twopi |
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| 39 | xprimm(iim + 1) = xprimm(1) |
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| 40 | |
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| 41 | END SUBROUTINE principal_cshift |
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| 42 | |
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| 43 | END MODULE principal_cshift_m |
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