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Fri, Nov 1, 01:06

gtree
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#!/usr/bin/env python
from pNbody import *
from pNbody import libgrid
from pNbody import myNumeric
import time
from optparse import OptionParser
########################################
#
# parser
#
########################################
def parse_options():
usage = "usage: %prog [options] file"
parser = OptionParser(usage=usage)
parser.add_option("-t",
action="store",
dest="ftype",
type="string",
default = 'gadget',
help="type of the file",
metavar=" TYPE")
parser.add_option("-i",
action="store",
dest="input_file",
type="string",
default = None,
help="input file",
metavar=" FILE")
parser.add_option("--eps",
action="store",
dest="eps",
type="float",
default = 0.25,
help="softening length",
metavar=" FLOAT")
parser.add_option("--dTime",
action="store",
dest="dTime",
type="float",
default = 0.1,
help="time step",
metavar=" FLOAT")
parser.add_option("--TimeEnd",
action="store",
dest="TimeEnd",
type="float",
default = 10,
help="final time",
metavar=" FLOAT")
parser.add_option("--dOutputTime",
action="store",
dest="dOutputTime",
type="float",
default = 0,
help="time between output",
metavar=" FLOAT")
parser.add_option("--dStatTime",
action="store",
dest="dStatTime",
type="float",
default = 0,
help="time between system statistics",
metavar=" FLOAT")
parser.add_option("--theta",
action="store",
dest="theta",
type="float",
default = 0.7,
help="time between output",
metavar=" FLOAT")
(options, args) = parser.parse_args()
return options
##############################################
# write integrals
##############################################
def WriteIntegrals(fe,t,T,U,C,P,L,I):
E = T + U
Cx = C[0]
Cy = C[1]
Cz = C[2]
Px = P[0]
Py = P[1]
Pz = P[2]
Lx = L[0]
Ly = L[1]
Lz = L[2]
Ix = I[0]
Iy = I[1]
Iz = I[2]
line = "%20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e %20.10e\n"%(t,E,T,U,Cx,Cy,Cz,Px,Py,Pz,Lx,Ly,Lz,Ix,Iy,Iz)
fe.write(line)
fe.flush()
##############################################
# compute energy kin
##############################################
def ComputeEnergyKin(nb):
return sum(0.5 * nb.mass * (nb.vel[:,0]**2 + nb.vel[:,1]**2 + nb.vel[:,2]**2))
##############################################
# compute energy pot
##############################################
def ComputeEnergyPot(nb,eps):
return sum(nb.Epot(eps))
##############################################
# compute mass center
##############################################
def ComputeMassCenter(nb):
mass_tot = sum(nb.mass)
cmx = sum(nb.pos[:,0]*nb.mass) / mass_tot
cmy = sum(nb.pos[:,1]*nb.mass) / mass_tot
cmz = sum(nb.pos[:,2]*nb.mass) / mass_tot
return array([cmx,cmy,cmz])
##############################################
# compute momentum
##############################################
def ComputeMomentum(nb):
px = sum(nb.vel[:,0]*nb.mass)
py = sum(nb.vel[:,1]*nb.mass)
pz = sum(nb.vel[:,2]*nb.mass)
return array([px,py,pz])
##############################################
# compute angular momentum
##############################################
def ComputeAngularMomentum(nb):
return nb.Ltot()
##############################################
# intertial momentum
##############################################
def ComputeInertialMomentum(nb):
return nb.minert()
################################################################################
#
# MAIN
#
################################################################################
options = parse_options()
ftype = options.ftype
input_file = options.input_file
eps = options.eps
dOutputTime = options.dOutputTime
dStatTime = options.dStatTime
TimeEnd = options.TimeEnd
dTime = options.dTime
ErrTolTheta = options.theta
# open file
print "open initial conditions"
nb = Nbody(input_file,ftype=ftype)
print "build the tree"
nb.getTree(ErrTolTheta=ErrTolTheta,force_computation=True)
print "compute acceleration"
nb.acc = nb.TreeAccel(nb.pos,eps)
# some init
Time = nb.atime
Step = 0
CPUTimeRef = time.time()
CPUTime = 0.0
OutputTime = 0
OutputNumber = 0
StatTime = 0
# open output
fi = open("integrals.dat",'w')
fi.write("# t E T U Cx Cy Cz Px Py Pz Lx Ly Lz Ix Iy Iz\n")
#####################
# main loop
#####################
while (Time<TimeEnd):
# write output
if (Time >= OutputTime):
outputname = 'snap_%04d'%(OutputNumber)
print "Step %06d writing %s"%(Step,outputname)
nb.rename(outputname)
nb.atime = Time
nb.write()
OutputNumber += 1
OutputTime = Time + dOutputTime
print "Step %06d Time = %8.3f CPUTime=%8.1f"%(Step,Time,CPUTime)
# leap-frog, first stage
nb.vel = nb.vel + nb.acc*dTime/2. # vel to step n+1/2
nb.pos = nb.pos + nb.vel*dTime # pos to step n+1
# make the tree
nb.getTree(ErrTolTheta=ErrTolTheta,force_computation=True)
# compute acceleration
nb.acc = nb.TreeAccel(nb.pos,eps)
# leap-frog, second stage
nb.vel = nb.vel + nb.acc*dTime/2. # vel to step n+1
# increment time
Time = Time + dTime
Step = Step + 1
CPUTime = time.time()-CPUTimeRef
# write stats
if (Time >= StatTime):
print "Compute System Statistic"
# compute integrals
# for the potential computation, we do not need to recompute the tree
T = ComputeEnergyKin(nb)
U = ComputeEnergyPot(nb,eps)
C = ComputeMassCenter(nb)
P = ComputeMomentum(nb)
L = ComputeAngularMomentum(nb)
I = ComputeInertialMomentum(nb)
WriteIntegrals(fi,Time,T,U,C,P,L,I)
StatTime = Time + dStatTime
# close files
fi.close()

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