将三个功能合并为一个

Question

我正在构建一个将轨道元素转换为笛卡尔坐标的程序。

我想创建一个函数来执行此操作，将轨道元素转换为笛卡尔坐标，但我无法让它工作。这是我第一次使用 fortran，所以我还在适应它。

program conversion

implicit none
real*8 :: EC, A, IC, OM, W, TA, X, Y, Z
real*8, external :: XCARTISIAN, YCARTISIAN, ZCARTISIAN, r

print *, "Insert Oribtal Elements (EC, A, IC, OM, W, TA): "
read *, EC, A, IC, OM, W, TA, X, Y, Z


X = XCARTISIAN(EC, A, IC, OM, W, TA)
Y = YCARTISIAN(EC, A, IC, OM, W, TA)
Z = ZCARTISIAN(EC, A, IC, OM, W, TA)

print *, "X : ", X, "Y : ", Y, "Z : ", Z

end program conversion



real*8 function XCARTISIAN(EC, A, IC, OM, W, TA)

implicit none
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: XCARTISIAN, r

r = A(1-EC**2)/(1+EC*COS(TA))
XCARTISIAN = r(COS(OM)*COS(W+TA)-SIN(OM)*SIN(W+TA)*COS(IC))

return

end function XCARTISIAN

real*8 function YCARTISIAN(EC, A, IC, OM, W, TA)

implicit none
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: YCARTISIAN

r = A(1-EC**2)/(1+EC*COS(TA))
YCARTISIAN = r(SIN(OM)*COS(W+TA)+COS(OM)*SIN(W+TA)*COS(IC))

return

end function YCARTISIAN


real*8 function ZCARTISIAN(EC, A, IC, OM, W, TA)

implicit none
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: ZCARTISIAN

r = A(1-EC**2)/(1+EC*COS(TA))
ZCARTISIAN = r(SIN(W+F)*SIN(IC)

return

end function ZCARTISIAN

我怎样才能使它工作并创建一个函数来执行此操作而不是分别为 X、Y 和 Z 创建三个单独的函数？

转换公式如下：

X = r(COS(OM)*COS(W+TA)-SIN(OM)*SIN(W+TA)*COS(IC))
Y = r(SIN(OM)*COS(W+TA)+COS(OM)*SIN(W+TA)*COS(IC))
Z = r(SIN(W+F)*SIN(IC)

其中，

r = A(1-EC**2)/(1+EC*COS(TA))

Answer 1

也许把你的函数放到一个模块中？

MODULE ORBITCANDY 
IMPLICIT NONE
PRIVATE

TYPE(Cart_typ)
  REAL*8 X
  REAL*8 Y
  REAL*8 Z
END TYPE Cart_typ
PUBLIC :: Cart_Typ

TYPE(OE_typ)
  REAL*8 EC
  REAL*8 A
  REAL*8 IC
  REAL*8 OM
  REAL*8 W
  REAL*8 TA
END TYPE OE_typ
PUBLIC :: OE_Typ

PUBLIC :: OE2CART

CONTAINS

function OE2Cart(OE)
implicit none
TYPE(OE_Typ) , INTENT(IN   ) :: OE
TYPE(Cart_Typ)               :: OE2Cart
real*8                       :: EC, A, IC, OM, W, TA
real*8                       :: XCARTISIAN, r

EC = OE%EC
A  = OE%A
IC = OE%IC
OM = OE%OM
W  = OE%W
TA = OE%TA
OE2Cart%X = XCARTISIAN(EC, A, IC, OM, W, TA)
OE2Cart%Y = YCARTESIAN(EC, A, IC, OM, W, TA)
OE2Cart%Z = ZCARTESIAN(EC, A, IC, OM, W, TA)

RETURN
END FUNCTION OE2CART

!%%%%%%%%%%%%%%
real*8 function YCARTISIAN(EC, A, IC, OM, W, TA)
implicit none
TYPE(OE_Typ) , INTENT(IN   ) :: OE
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: XCARTISIAN, r

r = A(1-EC**2)/(1+EC*COS(TA))
XCARTISIAN = r(COS(OM)*COS(W+TA)-SIN(OM)*SIN(W+TA)*COS(IC))

return
end function XCARTISIAN

!%%%%%%%%%%%%%%
real*8 function YCARTISIAN(EC, A, IC, OM, W, TA)
implicit none
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: YCARTISIAN

r = A(1-EC**2)/(1+EC*COS(TA))
YCARTISIAN = r(SIN(OM)*COS(W+TA)+COS(OM)*SIN(W+TA)*COS(IC))

return
end function YCARTISIAN


   !%%%%%%%%%%%%%%
real*8 function ZCARTISIAN(EC, A, IC, OM, W, TA)

implicit none
real*8, intent(in) :: EC, A, IC, OM, W, TA
real*8 :: ZCARTISIAN

r = A(1-EC**2)/(1+EC*COS(TA))
ZCARTISIAN = r(SIN(W+F)*SIN(IC)

return

end function ZCARTISIAN

END MODULE ORBITCANDY

还有一个用于 R，然后是 CART2GEODETIC，等等...

program conversion
USE ORBITCANDY
implicit none
TYPE(OE_Typ)   :: OE
TYPE(Cart_Typ) :: Cart
real*8, external :: r ! Add this one above

print *, "Insert Oribtal Elements (EC, A, IC, OM, W, TA): "
read *, OE%EC, OE%A, OE%IC, OE%OM, OE%W, OE%TA

print *, "Insert Oribtal Elements (EC, A, IC, OM, W, TA): "
read *, OE%EC, OE%A, OE%IC, OE%OM, OE%W, OE%TA

XYZ = OE2CART(OE)
print *, "X : ", XYZ%X, "Y : ", XYZ%Y, "Z : ", XYZ%Z

end program conversion

iPad里面没有编译器，肯定是打错了...

Answer 2

最直接的做法是制作一个子程序。最好放在一个模块中，但这是可选的（但恕我直言，所有函数和子例程都应该在某个模块中）。

subroutine XYZCARTISIAN(XCARTISIAN, YCARTISIAN, ZCARTISIAN, EC, A, IC, OM, W, TA)

  implicit none
  real*8 :: XCARTISIAN, YCARTISIAN, ZCARTISIAN
  real*8, intent(in) :: EC, A, IC, OM, W, TA
, r

  r = A(1-EC**2)/(1+EC*COS(TA))

  XCARTISIAN = r*(COS(OM)*COS(W+TA)-SIN(OM)*SIN(W+TA)*COS(IC))
  YCARTISIAN = r*(SIN(OM)*COS(W+TA)+COS(OM)*SIN(W+TA)*COS(IC))
  ZCARTISIAN = r*(SIN(W+F)*SIN(IC)
end subroutine

这也会更快，因为您只计算 r 一次并且只调用一个子程序。

请注意：

real*8完全不标准，不是Fortran。
使用缩进使您的代码更具可读性。
那里不需要return，我们只是过早地return。

将三个功能合并为一个

Merging three functions into one

fortran

physics

function