js-pert

Program evaluation and review technique

Given a set of activities with pessimistic, optimistic, probable times and the set of dependencies, will provide:

• expected time for every activity
• variance for every activity
• the description of the activity on node [AON] network diagram with predecessors and successors
• earliest start [ES] times for every node
• earliest finish [EF] times for every node
• latest start [LS] times for every node
• latest finish [LF] times for every node
• slack for every node
• critical path description

With the pert description will also provide a function to calculate the probability to complete the project in x days.

Install

npm install js-pert --save

Example

Please look at this example.

Documentation

jsPERT

The default exported function allow you to retrieve the description of the PERT network.

Given activities:

{
  [key: string]: {
    id: string;
    optimisticTime: number;
    mostLikelyTime: number;
    pessimisticTime: number;
    predecessors: string[];
  };
}

You can use jsPERT as follow:

import jsPERT from 'js-pert';

const pert = jsPERT(activities);

console.log('PERT', pert);

Should log the PERT description in following shape:

{
  activitiesParams: {
    [key: string]: {
      expectedTime: number;
      variance: number;
    };
  };
  network: {
    [key: string]: {
      successors: string[];
      predecessors: string[];
    };
  };
  earliestFinishTimes: {
    [key: string]: number;
  };
  latestStartTimes: {
    [key: string]: number;
  };
  earliestStartTimes: {
    [key: string]: number;
  };
  latestFinishTimes: {
    [key: string]: number;
  };
  slack: {
    [key: string]: number;
  };
  criticalPath: string[];
}

pertProbability

You can get the probability of completing the project in less than x days submitting the PERT description and x in the pertProbability ancillary function.

import { pertProbability } from 'js-pert';

const Pz = pertProbability(pert, 22);

console.log('P(x<22):', Pz);

License

See the LICENSE file for license rights and limitations (MIT).