levyrandom_function

import random
from datetime import datetime
from scipy.stats import levy

random.seed(datetime.now())

def direction(previous_direction):
    """pick an initial random direction with uniform distribution"""
    directions = ['+1', '-1']
    if previous_direction == '0':
        direction_idx = random.randint(0, 1)
    elif previous_direction == '+1':
        direction_idx = 0
    elif previous_direction == '-1':
        direction_idx = 1

    #direction = directions[direction_idx]

    # custom parameters
    loc = 0
    scale = 1
    switch_threshold = 50

    """direction inversion using a random pick from levy distribution"""
    r = levy.rvs(loc, scale)  #generate random number with levy distribution

    # use > to invert direction on tail
    # use < to invert direction on head
    if r > switch_threshold:
        direction_idx = 1 if direction_idx==0 else 0
        #print(str(r)+'\tinverted direction => '+directions[direction_idx])
    #else:
        #print(str(r)+'\t'+directions[direction_idx])

    #print(directions[direction_idx])

    return(directions[direction_idx]) #returns the direction the function has chosen as a string of either +1 or -1