vctcnv.f
72 lines
| 2.1 KiB
| text/x-fortran
|
FortranFixedLexer
| r0 | C $Id: vctcnv.f 3304 2011-01-17 15:25:59Z brideout $ | |||
| C | ||||
| SUBROUTINE VCTCNV(FX,FY,FZ,X,Y,Z,FR,FT,FP,R,THETA,PHI,IMODE) | ||||
| C | ||||
| C jmh - 11/79 ans fortran 66 | ||||
| C | ||||
| C VCTCNV converts between the cartesian and spherical coordinate | ||||
| C representations of a vector field f. (FX,FY,FZ) are the | ||||
| C components of the field at (X,Y,Z). (FR,FT,FP) are the | ||||
| C components of the field at (R,THETA,PHI) in the directions of | ||||
| C increasing R, increasing THETA and increasing PHI. if IMODE=1, | ||||
| C (FX,FY,FZ,X,Y,Z) -> (FR,FT,FP,R,THETA,PHI). if IMODE=2, | ||||
| C (FR,FT,FP,R,THETA,PHI) -> (FX,FY,FZ,X,Y,Z). THETA and PHI are | ||||
| C in degrees. | ||||
| C | ||||
| C Input: | ||||
| C IMODE - 1 cartesian to spherical | ||||
| C 2 spherical to cartesian | ||||
| C | ||||
| C Input, output: | ||||
| C FX,FY,FZ - cartesian vector field components | ||||
| C X,Y,Z - cartesian vector field coordinates | ||||
| C FR,FT,FP - spherical vector field components | ||||
| C R,THETA,PHI - spherical vector field coordinates | ||||
| C | ||||
| C .. Scalar Arguments .. | ||||
| DOUBLE PRECISION FP,FR,FT,FX,FY,FZ,PHI,R,THETA,X,Y,Z | ||||
| INTEGER IMODE | ||||
| C .. | ||||
| C .. Local Scalars .. | ||||
| DOUBLE PRECISION CP,CT,DTR,P,RHO2,RLMIN,SP,ST,T | ||||
| C .. | ||||
| C .. Intrinsic Functions .. | ||||
| INTRINSIC ABS,DATAN2,DCOS,DMAX1,DSIN,DSQRT,SIGN | ||||
| C .. | ||||
| C .. Data statements .. | ||||
| DATA DTR/.0174532925199D0/,RLMIN/1.D-38/ | ||||
| C .. | ||||
| C | ||||
| IF (IMODE.EQ.2) THEN | ||||
| C | ||||
| T = DTR*THETA | ||||
| P = DTR*PHI | ||||
| CT = DCOS(T) | ||||
| ST = DSIN(T) | ||||
| CP = DCOS(P) | ||||
| SP = DSIN(P) | ||||
| X = R*ST*CP | ||||
| Y = R*ST*SP | ||||
| Z = R*CT | ||||
| FX = ST*CP*FR + CT*CP*FT - SP*FP | ||||
| FY = ST*SP*FR + CT*SP*FT + CP*FP | ||||
| FZ = CT*FR - ST*FT | ||||
| ELSE | ||||
| C | ||||
| RHO2 = X*X + Y*Y | ||||
| R = DSQRT(RHO2+Z*Z) | ||||
| THETA = DATAN2(DSQRT(RHO2),SIGN(1.D0,Z)*DMAX1(ABS(Z),RLMIN)) | ||||
| PHI = DATAN2(Y,SIGN(1.D0,X)*DMAX1(ABS(X),RLMIN)) | ||||
| CT = DCOS(THETA) | ||||
| ST = DSIN(THETA) | ||||
| CP = DCOS(PHI) | ||||
| SP = DSIN(PHI) | ||||
| THETA = THETA/DTR | ||||
| PHI = PHI/DTR | ||||
| FR = ST*CP*FX + ST*SP*FY + CT*FZ | ||||
| FT = CT*CP*FX + CT*SP*FY - ST*FZ | ||||
| FP = -SP*FX + CP*FY | ||||
| END IF | ||||
| RETURN | ||||
| C | ||||
| END | ||||
