dgoldberg/streamice/eta_gl_streamice_prime.F

#include "CPP_OPTIONS.h"

      _RL FUNCTION ETA_GL_STREAMICE_PRIME (X, M1, M2, Y0, W)

!      This function returns the derivative of ETA_GL_STREAMICE
!      w.r.t. its first argument


!     X: input variable
!     M1: slope of y where x<0
!     M2: slope of y where x>0
!     Y0: value of y at 0
!     W: width of smoothing

       _RL X, M1, M2, Y0, W
       _RL TMP1, PI

       IF (X<-1.0*W/2.0) THEN
         ETA_GL_STREAMICE_PRIME = M1
       ELSEIF(X>W/2.0) THEN
         ETA_GL_STREAMICE_PRIME = M2
       ELSE
         PI = 3.14159265358979323844D0
         TMP1 = SIN (PI*X/W)
         ETA_GL_STREAMICE_PRIME = 
     &     M1/2 * (1+TMP1) + 
     &     M2/2 * (1-TMP1)
       ENDIF

       RETURN
       END 
1	#include "CPP_OPTIONS.h"
2
3	_RL FUNCTION ETA_GL_STREAMICE_PRIME (X, M1, M2, Y0, W)
4
5	! This function returns the derivative of ETA_GL_STREAMICE
6	! w.r.t. its first argument
7
8
9	! X: input variable
10	! M1: slope of y where x<0
11	! M2: slope of y where x>0
12	! Y0: value of y at 0
13	! W: width of smoothing
14
15	_RL X, M1, M2, Y0, W
16	_RL TMP1, PI
17
18	IF (X<-1.0*W/2.0) THEN
19	ETA_GL_STREAMICE_PRIME = M1
20	ELSEIF(X>W/2.0) THEN
21	ETA_GL_STREAMICE_PRIME = M2
22	ELSE
23	PI = 3.14159265358979323844D0
24	TMP1 = SIN (PI*X/W)
25	ETA_GL_STREAMICE_PRIME =
26	& M1/2 * (1+TMP1) +
27	& M2/2 * (1-TMP1)
28	ENDIF
29
30	RETURN
31	END