wbs-uncertainty.py

"""
Schedule Work Breakdown Structure Uncertainty with Monte Carlo Simulations
"""
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

def simulate(wbs, n=100000, proba=0.9):
    """ Simulate the possible completion time of a WBS project.
    Parameters
    ----------
    wbs: dict {str: (int, int, int)}
      Work Breakdown Structure
    n: int
      Number of simulations
    proba: float
      Probability of interest
    """
  
    values = np.empty((0, n), np.float)
    for (mn, lk, mx) in wbs.values():
        if mn == mx:
            values = np.append(values, [np.zeros(n) + mn], axis=0)
        else:
            values = np.append(values, [np.random.triangular(left=mn, mode=lk, right=mx, size=n)], axis=0)
    
    sample = values.sum(axis=0)   
    sns.set_style("whitegrid")
    graph = sns.ecdfplot(sample)
    graph.axhline(y=proba, xmin=0, xmax=max(sample), color="red", ls="--", lw=1.5, visible=True, label="aaa")


# provide the duration range for each task in the WBS as follows (min, likely, max)
wbs = {
    "task1": (3, 5, 7),
    "task2": (1, 2, 6),
    "task3": (3, 4, 5),
    "task4": (2, 4, 8),
    "task5": (1, 2, 6),
    "task6": (1, 5, 7),
    "task7": (1, 2, 7),
    "task8": (1, 1, 1),
}
simulate(wbs)