Critical Path Method (CPM) Example

The Critical Path Method (CPM) is a project scheduling technique used to determine the sequence of activities that directly affects the total project duration.
By identifying the critical path—the longest sequence of dependent tasks—you can see which activities have zero slack and must be completed on time to avoid delaying the project.

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📊 CPM Network Diagram

Activity – Description – Predecessors

Activity	Description	Predecessors
A	Clear site	-
B	Bring utilities to site	-
C	Excavate	A
D	Pour foundation	C
E	Outside plumbing	B, C
F	Frame house	D
G	Do electric wiring	F
H	Lay floor	G
I	Lay roof	F
J	Inside plumbing	E, H
K	Shingling	I
L	Outside sheathing insulation	F, J
M	Install windows and outside doors	F
N	Do brick work	L, M
O	Insulate walls and ceiling	G, J
P	Cover walls and ceiling	O
Q	Insulate roof	I, P
R	Finish interior	P
S	Finish exterior	I, N
T	Landscape	S

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📂 Project Structure

critical-path-method/
├── docs/
│   └── cpm.png                # CPM diagram
├── cpm_tasks.xlsx              # Excel file with job data
├── main.py                     # Python script
└── README.md                   # This file

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▶️ How to Run

Install dependencies:

uv add pycritical pandas openpyxl

Run from the project root:

uv run main.py

The script will:

1. Load tasks from cpm_tasks.xlsx (sheet: example).
2. Run CPM with pyCritical.
3. Print the CPM results.
4. Display a Gantt chart.

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📚 References

• pyCritical GitHub
• Critical Path Method – Wikipedia