def __init__(self, length, dataList=None):
self.motionModel = MotionModel()
self.sensorModel = SensorModel()
self.sensorModel.loadData(dataList)
self._path_data_count = self.sensorModel.sampleSize
self._x_max = 0.0
self._x_center = 0.0
self._particles_count = 100
self._path_length = length
self.initSample(2, 10.8)
class ParticleFilter:
def __init__(self, length, dataList=None):
self.motionModel = MotionModel()
self.sensorModel = SensorModel()
self.sensorModel.loadData(dataList)
self._path_data_count = self.sensorModel.sampleSize
self._x_max = 0.0
self._x_center = 0.0
self._particles_count = 100
self._path_length = length
self.initSample(2, 10.8)
@property
def particles(self):
return self._particles
@property
def x_max(self):
return self._x_max
@property
def x_center(self):
return self._x_center
@property
def path_length(self):
return self._path_length
def accept(self, data, direction=1):
isBelievable = self.sensorModel.accept(data, direction)
return isBelievable
def updateParticles(self, step, isBelievable):
for p in self._particles:
# update motion model
p.pos = self.motionModel.update(p.pos, step, isBelievable)
# update sensor model
if isBelievable:
diff, pos = self.sensorModel.evaluate(p.pos / self._path_length)
fit = diff # + 40*abs(pos-p.x/path_length)
p.w *= math.exp(-LAMBDA * fit)
# compute x_max, x_center
def computePositions(self):
# compute x where w max
p_w_max = self._particles[0]
for p in self._particles:
if p.w >= p_w_max.w:
p_w_max = p
self._x_max = p_w_max.pos
nu = sum(p.w for p in self._particles)
if nu != 0.0:
self._x_center = sum(p.w / nu * p.pos for p in self._particles)
else:
self._x_center = 0.0
# Normalize weights
def normalizeWeights(self):
nu = sum(p.w for p in self._particles)
if nu:
for p in self._particles:
p.w = p.w / nu
# Initialise particles. (mode=0:random, mode=1:uniform)
def initSample(self, mode=1, nearPos=0.0):
uniform_weight = 1.0 / self._particles_count
self._particles = []
self._iter = 0
if mode == 0: # random
self._particles = Particle.create_random_particles(self._particles_count, uniform_weight)
elif mode == 1: # uniform
self._particles = Particle.create_uniform_particles(self._particles_count, uniform_weight)
elif mode == 2: # near
for _ in range(0, self._particles_count):
pos = norm.rvs(nearPos, RESAMPLE_AROUND_MAX_STANDARD_DEVIATION * 3)
if pos < 0.0 or pos > self._path_length:
pos = nearPos
new_particle = Particle(pos, uniform_weight)
self._particles.append(new_particle)
# Resample particles.
def resampleParticles(self, uniform_percent=RESAMPLE_UNIFORM_PERCENT):
# create a weighted distribution, for fast picking
dist = WeightedDistribution(self._particles)
uniform_weight = 1.0 / self._particles_count
u_count = (int)(self._particles_count * uniform_percent * math.exp(-0.2 * self._iter)) # uniform count
self._iter += 1
max_around_count = (int)(self._particles_count * RESAMPLE_AROUND_MAX_PERCENT) # max around count
pick_count = self._particles_count - u_count - max_around_count # pick count from exist particles
# uniform
new_particles = self.create_uniform_particles(u_count, uniform_weight)
# max around
for i in xrange(0, max_around_count):
new_particle = Particle(norm.rvs(self._x_max, RESAMPLE_AROUND_MAX_STANDARD_DEVIATION), uniform_weight)
new_particles.append(new_particle)
# pick from exist particles
for i in xrange(0, pick_count):
p = dist.pick()
if p is None: # No pick b/c all totally improbable
new_particle = Particle(random.uniform(0, 1) * self._path_length, uniform_weight)
else:
new_particle = Particle(p.pos, p.w)
new_particles.append(new_particle)
self._particles = new_particles
# If isBelievable is Fasle, only move particles, not update weights or resample
def getPredict(self, isBelievable):
self.updateParticles(SPPED, isBelievable)
self.computePositions()
if isBelievable:
self.normalizeWeights()
self.resampleParticles()
return self._x_max
def create_random_particles(self, particles_num, w):
return [Particle(random.uniform(0, 1) * self._path_length, w) for _ in xrange(0, particles_num)]
def create_uniform_particles(self, particles_num, w):
return [
Particle((i + random.uniform(0, 1)) / particles_num * self._path_length, w)
for i in xrange(0, particles_num)
]