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#!/usr/bin/python
# Copyright 2006-2007 Nanorex, Inc. See LICENSE file for details.
from jelloGui import *
import sys
import random
import time
import types
import string
from math import cos, sin, sqrt
PROFILING = True
if PROFILING:
import hotshot, hotshot.stats
GOT_PYREX = False
try:
import comp
GOT_PYREX = True
except ImportError:
pass
N = 4
# milliseconds
ANIMATION_DELAY = 50
"""I think this is the correct way to
scale stiffness and viscosity.
"""
RADIUS = 15 / N**.5
MASS = 3.0e-6 / N**2
DT = 3.0e-3
STIFFNESS = 1.0e-8 * N
VISCOSITY = 3.0e-9 * N
DTM = (DT ** 2) / MASS
TIME_STEP = 0.2
MAXTIME = 1.0e20
A = 3.0e-8
def addvec(u, v):
return (u[0] + v[0], u[1] + v[1])
def subvec(u, v):
return (u[0] - v[0], u[1] - v[1])
def scalevec(u, k):
return (u[0] * k, u[1] * k)
# Keep the old, current and new versions of u
# in here, along with x.
class Computronium:
def __init__(self, owner):
self.owner = owner
self.u = u = N**2 * [ (0.0, 0.0) ]
self.u_old = N**2 * [ (0.0, 0.0) ]
self.u_new = N**2 * [ (0.0, 0.0) ]
self.x = x = [ ] # nominal positions
for i in range(N):
for j in range(N):
x.append((1. * j / N,
1. * i / N))
self.forceTerms = [ ]
# set up the force terms
for i in range(N):
for j in range(N - 1):
self.forceTerms.append((i * N + j,
i * N + j + 1))
for i in range(N - 1):
for j in range(N):
self.forceTerms.append((i * N + j,
(i + 1) * N + j))
self.simTime = 0.0
def internalForces(self):
forces = self.zeroForces()
u, o = self.u, self.u_old
for i1, i2 in self.forceTerms:
D = subvec(u[i2], u[i1]) # relative displacement
P = subvec(o[i2], o[i1]) # previous relative displacement
f = addvec(scalevec(D, STIFFNESS),
scalevec(subvec(D, P), VISCOSITY / DT))
forces[i1] = addvec(forces[i1], f)
forces[i2] = subvec(forces[i2], f)
self.applyForces(forces)
def verletMomentum(self):
self_u, self_uold, self_unew = self.u, self.u_old, self.u_new
for i in range(N**2):
self_unew[i] = subvec(scalevec(self_u[i], 2),
self_uold[i])
def applyForces(self, f):
self_unew = self.u_new
index = 0
for i in range(N**2):
unew = self_unew[i]
fi = f[i]
self_unew[i] = (unew[0] + DTM * fi[0],
unew[1] + DTM * fi[1])
def zeroForces(self):
return N**2 * [ (0.0, 0.0) ]
def draw(self, cb, h, w):
# x is nominal position
# u is displacement
p = [ ]
a = 0.6
b = .5 * (1 - a)
for i in range(N**2):
xvec = self.x[i]
uvec = self.u[i]
cb(h * (a * (xvec[0] + uvec[0]) + b),
w * (a * (xvec[1] + uvec[1]) + b))
def rotate(self):
tmp = self.u_old
self.u_old = self.u
self.u = self.u_new
self.u_new = tmp
if GOT_PYREX:
# Keep the old, current and new versions of u
# in here, along with x.
class ComputroniumWithPyrex(Computronium):
def __init__(self, owner):
self.owner = owner
comp._setup(N)
def internalForces(self):
comp._internalForces(STIFFNESS, VISCOSITY/DT, DTM)
def verletMomentum(self):
comp._verletMomentum()
def applyForces(self, f):
comp._applyForces(f, DTM)
def draw(self, cb, h, w):
return comp._draw(cb, h, w)
def rotate(self):
return comp._rotate()
Computronium = ComputroniumWithPyrex
class Jello(JelloGui):
COLOR_CHOICES = (
QColor(Qt.red), QColor(Qt.yellow),
QColor(Qt.green), QColor(Qt.blue)
)
def __init__(self):
JelloGui.__init__(self, parent=None, name=None, modal=0, fl=0)
size = self.frame1.size()
self.width, self.height = size.width(), size.height()
self.comp = Computronium(self)
self.simTime = 0.0
self.timer = QTimer(self)
self.connect(self.timer, SIGNAL('timeout()'), self.timeout)
self.lastTime = time.time()
self.timer.start(ANIMATION_DELAY)
self.push = self.comp.zeroForces()
for i in range(N/2):
f = A * (.5*N - i) / (.5*N)
self.push[i] = (-f, f)
self.push[N*N-1 - i] = (f, -f)
self.painter = QPainter()
def pushButton1_clicked(self):
self.quit()
def quit(self):
self.app.quit()
def timeout(self):
try:
self.oneFrame()
except AssertionError, e:
import traceback
traceback.print_exc()
self.quit()
if self.simTime > MAXTIME:
self.app.quit()
def oneFrame(self):
# On each step we do verlet, using u_old and u to compute
# u_new. Then we move each particle from u to u_new. Then
# we move u to u_old, and u_new to u.
for i in range(int(TIME_STEP / DT)):
self.equationsOfMotion()
self.paintEvent(None)
def paintEvent(self, e):
p = self.painter
w, h = self.width, self.height
p.begin(self.frame1)
p.eraseRect(0, 0, w, h)
p.setPen(QPen(Qt.black))
p.setBrush(QBrush(Qt.blue))
def draw(x, y, de=p.drawEllipse, r=RADIUS):
de(x, y, r, r)
#self.comp.draw(draw, w, h)
self.comp.draw(draw, h, h)
p.end()
def equationsOfMotion(self):
comp = self.comp
t = self.simTime
self.simTime += DT
pushTime = 1.0
comp.verletMomentum()
comp.internalForces()
if t < pushTime:
comp.applyForces(self.push)
comp.rotate()
def main(n, maxTime=1.0e20):
global N, RADIUS, MAXTIME
N = n
RADIUS = 15 / n**.5
MAXTIME = maxTime
app = QApplication(sys.argv)
cr = Jello()
cr.app = app
app.setMainWidget(cr)
cr.show()
cr.update()
app.exec_loop()
if __name__ == "__main__":
if PROFILING:
prof = hotshot.Profile("jello.prof")
def m():
main(4, maxTime=30.0)
prof.runcall(m)
prof.close()
print 'Profiling run is finished, figuring out stats'
stats = hotshot.stats.load("jello.prof")
stats.strip_dirs()
stats.sort_stats('time', 'calls')
stats.print_stats(20)
sys.exit(0)
try:
n = string.atoi(sys.argv[1])
except:
n = 10
main(n)
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