Commit 77906fc7 authored by Luke Campagnola's avatar Luke Campagnola
Browse files

corrections to manifest

Add pure-python integrator to verlet chain example
parent 9a951318
recursive-include pyqtgraph *.py *.ui *.m README *.txt
recursive-include tests *.py *.ui
recursive-include examples *.py *.ui
recursive-include examples *.py *.ui *.gz *.cfg
recursive-include doc *.rst *.py *.svg *.png *.jpg
recursive-include doc/build/html *
recursive-include tools *
......
import pyqtgraph as pg
import numpy as np
import time
from .relax import relax
from . import relax
class ChainSim(pg.QtCore.QObject):
......@@ -52,7 +52,7 @@ class ChainSim(pg.QtCore.QObject):
self.mrel1[self.fixed[l2]] = 0
self.mrel2 = 1.0 - self.mrel1
for i in range(100):
for i in range(10):
self.relax(n=10)
self.initialized = True
......@@ -76,6 +76,10 @@ class ChainSim(pg.QtCore.QObject):
dt = now - self.lasttime
self.lasttime = now
# limit amount of work to be done between frames
if not relax.COMPILED:
dt = self.maxTimeStep
if self.lastpos is None:
self.lastpos = self.pos
......@@ -103,8 +107,9 @@ class ChainSim(pg.QtCore.QObject):
def relax(self, n=50):
# speed up with C magic
relax(self.pos, self.links, self.mrel1, self.mrel2, self.lengths, self.push, self.pull, n)
# speed up with C magic if possible
relax.relax(self.pos, self.links, self.mrel1, self.mrel2, self.lengths, self.push, self.pull, n)
self.relaxed.emit()
......@@ -2,9 +2,15 @@ import ctypes
import os
so = os.path.join(os.path.dirname(__file__), 'maths.so')
lib = ctypes.CDLL(so)
try:
lib = ctypes.CDLL(so)
COMPILED = True
except OSError:
COMPILED = False
lib.relax.argtypes = [
if COMPILED:
lib.relax.argtypes = [
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
......@@ -16,8 +22,49 @@ lib.relax.argtypes = [
ctypes.c_int,
]
def relax(pos, links, mrel1, mrel2, lengths, push, pull, iters):
def relax(pos, links, mrel1, mrel2, lengths, push, pull, iters):
nlinks = links.shape[0]
lib.relax(pos.ctypes, links.ctypes, mrel1.ctypes, mrel2.ctypes, lengths.ctypes, push.ctypes, pull.ctypes, nlinks, iters)
else:
def relax(pos, links, mrel1, mrel2, lengths, push, pull, iters):
lengths2 = lengths**2
for i in range(iters):
#p1 = links[:, 0]
#p2 = links[:, 1]
#x1 = pos[p1]
#x2 = pos[p2]
#dx = x2 - x1
#dist = (dx**2).sum(axis=1)**0.5
#mask = (npush & (dist < lengths)) | (npull & (dist > lengths))
##dist[mask] = lengths[mask]
#change = (lengths-dist) / dist
#change[mask] = 0
#dx *= change[:, np.newaxis]
#print dx
##pos[p1] -= mrel2 * dx
##pos[p2] += mrel1 * dx
#for j in range(links.shape[0]):
#pos[links[j,0]] -= mrel2[j] * dx[j]
#pos[links[j,1]] += mrel1[j] * dx[j]
for l in range(links.shape[0]):
p1, p2 = links[l];
x1 = pos[p1]
x2 = pos[p2]
dx = x2 - x1
dist2 = (dx**2).sum()
if (push[l] and dist2 < lengths2[l]) or (pull[l] and dist2 > lengths2[l]):
dist = dist2 ** 0.5
change = (lengths[l]-dist) / dist
dx *= change
pos[p1] -= mrel2[l] * dx
pos[p2] += mrel1[l] * dx
"""
Mechanical simulation of a chain using verlet integration.
Use the mouse to interact with one of the chains.
By default, this uses a slow, pure-python integrator to solve the chain link
positions. Unix users may compile a small math library to speed this up by
running the `examples/verlet_chain/make` script.
"""
import initExample ## Add path to library (just for examples; you do not need this)
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
from verlet_chain import ChainSim
import verlet_chain
sim = ChainSim()
sim = verlet_chain.ChainSim()
if verlet_chain.relax.COMPILED:
# Use more complex chain if compiled mad library is available.
chlen1 = 80
chlen2 = 60
linklen = 1
else:
chlen1 = 10
chlen2 = 8
linklen = 8
chlen1 = 80
chlen2 = 60
npts = chlen1 + chlen2
sim.mass = np.ones(npts)
sim.mass[chlen1-15] = 100
sim.mass[int(chlen1 * 0.8)] = 100
sim.mass[chlen1-1] = 500
sim.mass[npts-1] = 200
......@@ -31,8 +43,10 @@ sim.fixed[chlen1] = True
sim.pos = np.empty((npts, 2))
sim.pos[:chlen1, 0] = 0
sim.pos[chlen1:, 0] = 10
sim.pos[:chlen1, 1] = np.arange(chlen1)
sim.pos[chlen1:, 1] = np.arange(chlen2)
sim.pos[:chlen1, 1] = np.arange(chlen1) * linklen
sim.pos[chlen1:, 1] = np.arange(chlen2) * linklen
# to prevent miraculous balancing acts:
sim.pos += np.random.normal(size=sim.pos.shape, scale=1e-3)
links1 = [(j, i+j+1) for i in range(chlen1) for j in range(chlen1-i-1)]
links2 = [(j, i+j+1) for i in range(chlen2) for j in range(chlen2-i-1)]
......@@ -55,7 +69,8 @@ sim.push = np.concatenate([push1, push2, np.array([True], dtype=bool)])
sim.pull = np.ones(sim.links.shape[0], dtype=bool)
sim.pull[-1] = False
mousepos = sim.pos[0]
# move chain initially just to generate some motion if the mouse is not over the window
mousepos = np.array([30, 20])
def display():
......
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