levywalk

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

random.seed(datetime.now())

def direction():

    """pick an initial random direction with uniform distribution"""
    direction_xy = polarToCartesian(random.randint(0, 7))

    # custom parameters
    stride_normal = 1
    stride_long = 30
    loc = 0
    scale = 1
    threshold = 25

    """stride length using a random pick from levy distribution"""
    r = levy.rvs(loc, scale)

    # use < to enable stride on tail
    # use > to enable stride  on head
    stride = stride_normal if r < threshold else stride_long

    #print([direction_xy, stride])
    return([direction_xy, stride])

def polarToCartesian(direction):
    # 0 1 2
    # 7 b 3
    # 6 5 4
    return {
        0: [-1, -1],
        1: [-1,  0],
        2: [-1, +1],
        3: [ 0, +1],
        4: [+1, +1],
        5: [+1,  0],
        6: [+1, -1],
        7: [ 0, -1]
    } [direction]

### TEST
for t in range(10):
    print(direction())
###