16_5.py

import random

def throwNeedles(numNeedles):
    inCircle = 0
    for Needles in range(1, numNeedles + 1):
        x = random.random()
        y = random.random()
        if (x*x+y*y)**0.5 <= 1:
            inCircle += 1
    #1つの象限内の針のみ数えるため、4倍する
    return 4*(inCircle/float(numNeedles))

def getEst(numNeedles, numTrials):
    estimates = []
    for t in range(numTrials):
        piGuess = throwNeedles(numNeedles)
        estimates.append(piGuess)
    sDev = stdDev(estimates)
    curEst = sum(estimates)/len(estimates)
    print('Est =' + str(round(curEst, 5))+ ',', 'Std. dev =' + str(round(sDev, 5))+',', 'Needles ='+ str(numNeedles))
    return (curEst, sDev)

def estPi(precision, numTrials):
    numNeedles = 1000
    sDev = precision
    while sDev >= precision/1.96:
        curEst, sDev = getEst(numNeedles, numTrials)
        numNeedles *= 2
    return curEst