Dear all
I am trying to create a movie file of a monte carlo simulation at each time
step from the plot of matplotlib in python2.7.
The movie creation using ffmpeg is giving following error
Traceback (most recent call last):
File "code1.py", line 99, in <module>
print simulate(side, time, density)
File "code1.py", line 94, in simulate
t+=1
File "/Users/smaheshwari/anaconda2/lib/python2.7/contextlib.py", line 35, in
__exit__
self.gen.throw(type, value, traceback)
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/matplotlib/animation.py",
line 256, in saving
self.finish()
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/matplotlib/animation.py",
line 276, in finish
self.cleanup()
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/matplotlib/animation.py",
line 311, in cleanup
out, err = self._proc.communicate()
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/subprocess32.py",
line 927, in communicate
stdout, stderr = self._communicate(input, endtime, timeout)
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/subprocess32.py",
line 1713, in _communicate
orig_timeout)
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/subprocess32.py",
line 1769, in _communicate_with_poll
register_and_append(self.stdout, select_POLLIN_POLLPRI)
File
"/Users/smaheshwari/anaconda2/lib/python2.7/site-packages/subprocess32.py",
line 1748, in register_and_append
poller.register(file_obj.fileno(), eventmask)
ValueError: I/O operation on closed file
Please tell me what is the work around to this
I am using FFMpeg on MacOSX and this is the latest version
ffmpeg version N-78810-g4e05a12 Copyright (c) 2000-2016 the FFmpeg developers
built with Apple LLVM version 6.1.0 (clang-602.0.51) (based on LLVM 3.6.0svn)
configuration: --disable-yasm
libavutil 55. 19.100 / 55. 19.100
libavcodec 57. 27.101 / 57. 27.101
libavformat 57. 26.100 / 57. 26.100
libavdevice 57. 0.101 / 57. 0.101
libavfilter 6. 37.100 / 6. 37.100
libswscale 4. 0.100 / 4. 0.100
libswresample 2. 0.101 / 2. 0.101
My code is attached
sudeep
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import animation
import os
#create a 2D lattice with -1 and 1 spins
def lattice(side, density):
array = np.zeros((side,side))
halfside = np.int(side/2.)
SU = np.zeros((side, halfside))
SD = np.zeros((side, side-halfside))
places = int(SU.shape[0]*SU.shape[1]*density)
placessur = np.random.randint(0,SU.shape[0],places)
placessuc = np.random.randint(0,SU.shape[1],places)
SU[placessur, placessuc] = -1
SU[:,:] = -1
places = int(SD.shape[0]*SD.shape[1]*density)
placessur = np.random.randint(0,SD.shape[0],places)
placessuc = np.random.randint(0,SD.shape[1],places)
SD[placessur, placessuc] = 1
SD[:,:] = 1
array = np.column_stack((SU,SD))
array = array.astype(int)
return array
#compute total energy
def totenergy(syst, side):
Ene = 0
for i in range(len(syst[:,0])):
for j in range(len(syst[:,1])):
WF = syst[(i+1)%side,j] + syst[i,(j+1)%side] + syst[(i-1)%side,j] + syst[i,(j-1)%side]
Ene += -WF*syst[i,j] # Each neighbor gives energy 1.0
return Ene/2. # Each par counted twice
#compute magnetization
def magnet(syst, side):
return (1./(side**2))*(np.sum(syst))
#conditions
kbT, density, side, time = 2.0, 0.9, 4, 5
#writer of animation
FFMpegWriter = animation.writers['ffmpeg']
metadata = dict(title='MovieTest', artist='Matplotlib', comment='Movie support!')
writer = FFMpegWriter(metadata=metadata)
#figure for animation
fig = plt.figure()
#start simulation
def simulate(side, time, density):
syst = lattice(side,density)
energy = totenergy(syst, side)
magnetize = []
t = 0
with writer.saving(fig, 'simulation.avi', time):
while t<time:
#pick a point randomly
r = np.random.random_integers(1,side,2)
posr, posc = r[0]-1, r[1]-1
#neighbors
NRP, NRM = (posr+1)%side, (posr-1)%side
NCP, NCM = (posc+1)%side, (posc-1)%side
NRP, NRM = syst[NRP, posc], syst[NRM, posc]
NCP, NCM = syst[posr, NCP], syst[posr, NCM]
#change spin
syst[posr,posc] = (-1)*syst[posr,posc]
#calculate energy now
chenergy = energy - 2*(syst[posr,posc]*(NRP + NRM + NCP + NCM))
#determine if it should be accepted
if chenergy - energy < 0:
energy = chenergy
else:
eps = np.random.rand()
if eps < np.exp(-float((chenergy-energy)/kbT)):
energy = chenergy
else:
syst[posr,posc] = (-1)*syst[posr,posc]
#plot what happened
plt.matshow(syst, cmap=plt.cm.bwr)
writer.grab_frame()
plt.clf()
plt.pause(0.05)
t+=1
return syst
print simulate(side, time, density)
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