I am running a sample python simulation to predict a weighted & regular dice. I would like to use numba to help speed up my script but I receive an error:
<timed exec>:6: NumbaWarning:
Compilation is falling back to object mode WITH looplifting enabled because Function "roll" failed type inference due to: Untyped global name 'sum': cannot determine Numba type of <class 'builtin_function_or_method'>
File "<timed exec>", line 9:
<source missing, REPL/exec in use?>
Here is my original code: Is there another type of numba expression I can use instead? Right now I'm testing using input of 2500 rolls; want to get this down to 4 seconds (it's currently at 8.5 seconds).
%%time
from numba import jit
import random
import matplotlib.pyplot as plt
import numpy
@jit
def roll(sides, bias_list):
assert len(bias_list) == sides, "Enter correct number of dice sides"
number = random.uniform(0, sum(bias_list))
current = 0
for i, bias in enumerate(bias_list):
current += bias
if number <= current:
return i + 1
no_of_rolls = 2500
weighted_die = {}
normal_die = {}
#weighted die
for i in range(no_of_rolls):
weighted_die[i+1]=roll(6,(0.15, 0.15, 0.15, 0.15, 0.15, 0.25))
#regular die
for i in range(no_of_rolls):
normal_die[i+1]=roll(6,(0.167, 0.167, 0.167, 0.167, 0.167, 0.165))
plt.bar(*zip(*weighted_die.items()))
plt.show()
plt.bar(*zip(*normal_die.items()))
plt.show()
Using Random Choices
Refactored Code
import random
import matplotlib.pyplot as plt
no_of_rolls = 2500
# weights
normal_weights = (0.167, 0.167, 0.167, 0.167, 0.167, 0.165)
bias_weights = (0.15, 0.15, 0.15, 0.15, 0.15, 0.25)
# Replaced roll function with random.choices
# Reference: https://www.w3schools.com/python/ref_random_choices.asp
bias_rolls = random.choices(range(1, 7), weights = bias_weights, k = no_of_rolls)
normal_rolls = random.choices(range(1, 7), weights = normal_weights, k = no_of_rolls)
# Create dictionaries with same structure as posted code
weighted_die = dict(zip(range(no_of_rolls), bias_rolls))
normal_die = dict(zip(range(no_of_rolls), normal_rolls))
# Use posted plotting calls
plt.bar(*zip(*weighted_die.items()))
plt.show()
plt.bar(*zip(*normal_die.items()))
plt.show()
Performance
*Not including plotting.*
Original code: ~6 ms
Revised code: ~2 ms
(3x improvement, but not sure why the post mentions 8 seconds to run)
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