https://github.com/florentrenaud/nbody6tt
Tip revision: 8a4716382ead3ece116c48a4ae5c65f8c9534437 authored by Florent on 29 January 2015, 12:19:28 UTC
Nbody6 - 29 January 2015 (added GPU2/Build/.gitkeep)
Nbody6 - 29 January 2015 (added GPU2/Build/.gitkeep)
Tip revision: 8a47163
ran2.f
FUNCTION ran2(idum)
*
* Random number generator (Press et al. second edition).
* ------------------------------------------------------
implicit double precision(a-h,o-z)
INTEGER idum,IM1,IM2,IMM1,IA1,IA2,IQ1,IQ2,IR1,IR2,NTAB,NDIV
INTEGER idum2,j,k,iv,iy
COMMON/RAND2/ IY,IDUM2,IV(32),IXYZ(65)
c REAL ran2,AM,EPS,RNMX
PARAMETER (IM1=2147483563,IM2=2147483399,AM=1.d0/IM1,IMM1=IM1-1,
*IA1=40014,IA2=40692,IQ1=53668,IQ2=52774,IR1=12211,IR2=3791,
*NTAB=32,NDIV=1+IMM1/NTAB,EPS=1.2d-7,RNMX=1.d0-EPS)
* INTEGER idum2,j,k,iv(NTAB),iy
* SAVE iv,iy,idum2
* DATA idum2/123456789/, iv/NTAB*0/, iy/0/
* DATA IY,IDUM2,IV,IXYZ /0,123456789,32*0,65*0/
if (idum.le.0) then
idum=max(-idum,1)
idum2=idum
do 11 j=NTAB+8,1,-1
k=idum/IQ1
idum=IA1*(idum-k*IQ1)-k*IR1
if (idum.lt.0) idum=idum+IM1
if (j.le.NTAB) iv(j)=idum
11 continue
iy=iv(1)
endif
k=idum/IQ1
idum=IA1*(idum-k*IQ1)-k*IR1
if (idum.lt.0) idum=idum+IM1
k=idum2/IQ2
idum2=IA2*(idum2-k*IQ2)-k*IR2
if (idum2.lt.0) idum2=idum2+IM2
j=1+iy/NDIV
iy=iv(j)-idum2
iv(j)=idum
if(iy.lt.1)iy=iy+IMM1
ran2=min(AM*iy,RNMX)
return
END
C (C) Copr. 1986-92 Numerical Recipes Software ]vrt43D04.