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- c***********************************************************************
- c COORD_VH2B.F
- c***********************************************************************
- * PURPOSE: Converts from Heliocentric to Barycentric coords.
- * Velocity only
- * ARGUMENTS: Input is
- * nbod ==> number of bodies (must be less than NBMAX)
- * (integer)
- * mass(*) ==> masses (real array)
- * vxh(*),vyh(*),vzh(*) ==> heliocentric particle velocities
- * (real array)
- * Returned are
- * vxb(*),vyb(*),vzb(*) ==> bary. particle velocities
- * (real array)
- * msys ==> Total mass of of system
- * (real scalar)
- * Authors: Hal Levison
- * ALGORITHM: Obvious
- * WRITTEN: 11/14/96
- * REVISIONS: 11/21/96
- subroutine coord_vh2b(nbod,mass,vxh,vyh,vzh,vxb,vyb,vzb,msys)
- include '../swift.inc'
- c... Inputs:
- integer nbod
- real*8 mass(nbod)
- real*8 vxh(nbod),vyh(nbod),vzh(nbod)
- c... Outputs:
- real*8 vxb(nbod),vyb(nbod),vzb(nbod)
- c... Internals:
- real*8 msys,vxtmp,vytmp,vztmp
- integer n
- c----
- c... Executable code
- msys = mass(1)
- vxtmp =0.d0
- vytmp =0.d0
- vztmp =0.d0
- do n=2,nbod
- msys = msys +mass(n)
- vxtmp = vxtmp + mass(n)*vxh(n)
- vytmp = vytmp + mass(n)*vyh(n)
- vztmp = vztmp + mass(n)*vzh(n)
- enddo
- vxb(1) = -vxtmp/msys
- vyb(1) = -vytmp/msys
- vzb(1) = -vztmp/msys
- do n=2,nbod
- vxb(n) = vxh(n) + vxb(1)
- vyb(n) = vyh(n) + vyb(1)
- vzb(n) = vzh(n) + vzb(1)
- enddo
- return
- end ! coord_vh2b
- c--------------------------------------------------------------------------
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