def randomHypothesis(n, database):
"""
Returns a set of weights in the form of
a vector. These are to be used in the ANN.
The idea is that this should return a random
function. But a random ANN is the next best
thing.
It uses the Pearson r-correlation coefficient
to find out which of the the attributes that
might be connected.
n is the number of inputs of the function.
"""
#Generate the hidden layers!
#The number of hidden layers is geometrically random
numHiddenLayers = georand(0.8)
hiddenLayers = [0]*numHiddenLayers
#The number of nodes in each layer is geometrically random as well
for i in range(numHiddenLayers):
hiddenLayers[i] = georand(0.95)
#How many weights are required in the ANN?
numWeights = howManyWeightsInTheANN(hiddenLayers, numHiddenLayers, n)
out = [0.0]*(numWeights+numHiddenLayers+1)
out[0] = numHiddenLayers
index = 1
for element in hiddenLayers:
out[index] = element
index += 1
#Decide which attributes that are important
attributesInHypothesis = chooseAttributes(database, n)
#Set the first row of the network
numWeightsFirstRow = n*hiddenLayers[0]
for i in range(hiddenLayers[0]):
for j in range(n):
if(attributesInHypothesis[j] == True):
out[index] = random.gauss(0,10)
index += 1
#And then all of the other rows
for i in range(numWeights-numWeightsFirstRow):
if(random.random()<0.2):
out[index] = 10.0*random.gauss(0.0,1.0)
index += 1
return out
def perturb(_scores):
_valve = MyFuncs.SafetyValve(global_reps=10)
while _scores.score.std() == 0:
_valve.step("Failed to perturb:\n%s" % _scores)
for _indx, _score in _scores.score.iteritems():
_scores.set_value(_indx, "score", random.gauss(_score, (_score * 0.0000001)))
return _scores
def addRandomLittleJump(w):
"""
Adds a small and random change to the
weight vector.
"""
out = list(w)
counter = 1 + w[0]
for index in range(len(w)-counter):
#Try to keep the hypothesis sparse.
if(w[index+counter] != 0 or random.random() < 0.05):
out[index+counter] += random.gauss(0.0, 0.005)
return out
def generatePolygon(ctrX, ctrY, aveRadius, irregularity, spikeyness, numVerts):
'''Start with the centre of the polygon at ctrX, ctrY,
then creates the polygon by sampling points on a circle around the centre.
Randon noise is added by varying the angular spacing between sequential points,
and by varying the radial distance of each point from the centre.
https://github.com/the-mikedavis/randompolygons
Params:
ctrX, ctrY - coordinates of the "centre" of the polygon
aveRadius - in px, the average radius of this polygon, this roughly controls how large the polygon is, really only useful for order of magnitude.
irregularity - [0,1] indicating how much variance there is in the angular spacing of vertices. [0,1] will map to [0, 2pi/numberOfVerts]
spikeyness - [0,1] indicating how much variance there is in each vertex from the circle of radius aveRadius. [0,1] will map to [0, aveRadius]
numVerts - self-explanatory
Returns a list of vertices, in CCW order.
'''
import math, random
irregularity = clip(irregularity, 0, 1) * 2 * math.pi / numVerts
spikeyness = clip(spikeyness, 0, 1) * aveRadius
# generate n angle steps
angleSteps = []
lower = (2 * math.pi / numVerts) - irregularity
upper = (2 * math.pi / numVerts) + irregularity
sum = 0
for i in range(numVerts):
tmp = random.uniform(lower, upper)
angleSteps.append(tmp)
sum = sum + tmp
# normalize the steps so that point 0 and point n+1 are the same
k = sum / (2 * math.pi)
for i in range(numVerts):
angleSteps[i] = angleSteps[i] / k
# now generate the points
points = []
angle = random.uniform(0, 2 * math.pi)
for i in range(numVerts):
r_i = clip(random.gauss(aveRadius, spikeyness), 0, 2 * aveRadius)
x = ctrX + r_i * math.cos(angle)
y = ctrY + r_i * math.sin(angle)
points.append((int(x), int(y)))
angle = angle + angleSteps[i]
return points
def GenBoundedRandomNormal(meanVal,stdDev,lowerBound,upperBound):
aRand = gauss(meanVal,stdDev) # could also use: normalvariate()but gauss () is slightly faster.
while (aRand < lowerBound or aRand > upperBound):
aRand = random.gauss(meanVal,stdDev)
return aRand
