Random seed management in MLOps - Commands & Configuration

Introduction

When training machine learning models, results can change each time because of random choices inside the code. Random seed management means setting a fixed starting point for these random choices so you get the same results every time you run your code.

When you want to share your model training code and get the same results as your teammate.

When you need to debug your machine learning code and want consistent behavior.

When you want to compare different model versions fairly by controlling randomness.

When running automated tests on your ML pipeline that require stable outputs.

When logging experiments to track exact results for reproducibility.

Commands

Run a Python script that sets random seeds for Python, NumPy, and PyTorch to ensure reproducible results.

Terminal

python set_seed_example.py

Expected Output

Random number from Python random: 0.6394267984578837

Random number from NumPy: 0.3745401188473625

Random number from PyTorch: tensor([0.4963])

Key Concept

If you remember nothing else from this pattern, remember: setting the same random seed makes your experiments repeatable and results consistent.

Code Example

MLOps

import random
import numpy as np
import torch

def set_seed(seed: int):
    random.seed(seed)
    np.random.seed(seed)
    torch.manual_seed(seed)
    if torch.cuda.is_available():
        torch.cuda.manual_seed_all(seed)

set_seed(42)
print(f"Random number from Python random: {random.random()}")
print(f"Random number from NumPy: {np.random.rand()}")
print(f"Random number from PyTorch: {torch.rand(1)}")

Common Mistakes

Not setting the seed for all libraries that use randomness.

Some libraries like NumPy, Python random, and PyTorch have separate random states, so missing one causes different results.

Set the seed explicitly for each library you use in your code.

Setting the seed inside a loop or function repeatedly.

Resetting the seed multiple times can cause the same random number to appear repeatedly, reducing randomness.

Set the seed once at the start of your script or experiment.

Summary

Set a fixed random seed to make your machine learning experiments repeatable.

Apply the seed to all libraries that use randomness like Python random, NumPy, and PyTorch.

Run your code once after setting the seed to get consistent random numbers every time.

Practice

1. What is the main purpose of setting a random seed in machine learning experiments?

easy

A. To make the results reproducible and consistent across runs

B. To speed up the training process

C. To increase the randomness of the model

D. To reduce the size of the dataset

Solution

1. Step 1: Understand the role of randomness in experiments

   Randomness affects initialization and data shuffling, causing different results each run.

2. Step 2: Identify the effect of setting a seed

   Setting a seed fixes randomness so results are the same every time.

3. Final Answer:

   To make the results reproducible and consistent across runs -> Option A

4. Quick Check:

   Random seed = reproducibility [OK]

Hint: Random seed fixes randomness for repeatable results [OK]

Common Mistakes:

• Thinking seed speeds up training
• Believing seed increases randomness
• Confusing seed with dataset size

2. Which of the following Python code snippets correctly sets the random seed for both Python's random and NumPy libraries?

easy

A. import random
import numpy as np
random.seed(42)
np.seed(42)

B. import random
import numpy as np
random.seed(42)
np.random.seed(42)

C. import random
import numpy as np
random.seed = 42
np.random.seed = 42

D. import random
import numpy as np
random.set_seed(42)
np.set_seed(42)

Solution

1. Step 1: Recall correct seed setting methods

   Python's random uses random.seed(value), NumPy uses np.random.seed(value).

2. Step 2: Check each option's syntax

   import random import numpy as np random.seed(42) np.random.seed(42) uses correct functions. Others use non-existent set_seed, incorrect assignments to seed, or np.seed(42) which doesn't exist.

3. Final Answer:

   import random import numpy as np random.seed(42) np.random.seed(42) -> Option B

4. Quick Check:

   random.seed() and np.random.seed() are correct [OK]

Hint: Use .seed() method, not .set_seed or assignment [OK]

Common Mistakes:

• Using random.set_seed instead of random.seed
• Assigning seed as a variable instead of calling method
• Calling np.seed instead of np.random.seed

3. Consider the following Python code snippet:

import random
random.seed(123)
print([random.randint(1, 10) for _ in range(3)])
random.seed(123)
print([random.randint(1, 10) for _ in range(3)])

What will be the output?

medium

A. [[3, 2, 7], [4, 5, 6]]

B. [[1, 10, 2], [1, 10, 2]]

C. [[3, 2, 7], [3, 2, 7]]

D. [[1, 10, 2], [4, 5, 6]]

Solution

1. Step 1: Understand effect of setting seed before generating numbers

   Setting seed resets the random number generator to a fixed state.

2. Step 2: Predict output of two identical seed calls

   Both lists will be identical because the seed is reset before each list generation.

3. Final Answer:

   [3, 2, 7], [3, 2, 7] -> Option C

4. Quick Check:

   Same seed = same random sequence [OK]

Hint: Resetting seed repeats the same random sequence [OK]

Common Mistakes:

• Assuming different outputs after resetting seed
• Confusing seed effect with random state progression
• Ignoring that seed resets generator state

4. You have the following code snippet that aims to fix randomness but still produces different results each run:

import random
random.seed(42)
print(random.randint(1, 100))
import numpy as np
np.random.seed(42)
print(np.random.randint(1, 100))

What is the most likely reason for the non-reproducible results?

medium

A. The seed is set only for Python random and NumPy separately, but another library uses randomness

B. The random seed is set after generating random numbers

C. The seed value 42 is too small to fix randomness

D. The print statements cause randomness to reset

Solution

1. Step 1: Analyze seed setting for Python random and NumPy

   Seeds are set correctly for both libraries before generating numbers.

2. Step 2: Consider other sources of randomness

   If another library (e.g., TensorFlow, PyTorch) uses randomness but seed is not set there, results vary.

3. Final Answer:

   Seed set only for Python random and NumPy, but another library uses randomness -> Option A

4. Quick Check:

   All libraries need seed set for full reproducibility [OK]

Hint: Set seed in all libraries that use randomness [OK]

Common Mistakes:

• Thinking seed value size matters
• Believing print affects randomness
• Assuming seed order is wrong here

5. You want to ensure full reproducibility of a machine learning experiment using Python's random, NumPy, and PyTorch. Which of the following code snippets correctly sets seeds for all three libraries and disables nondeterministic behavior in PyTorch?

hard

A. import random
import numpy as np
import torch
random.seed(123)
np.random.seed(123)
torch.manual_seed(123)

B. import random
import numpy as np
import torch
random.seed(123)
np.random.seed(123)
torch.manual_seed(123)
torch.set_deterministic(True)

C. import random
import numpy as np
import torch
random.seed(123)
np.random.seed(123)
torch.manual_seed(123)
torch.deterministic = True

D. import random
import numpy as np
import torch
random.seed(123)
np.random.seed(123)
torch.manual_seed(123)
torch.use_deterministic_algorithms(True)

Solution

1. Step 1: Set seeds for Python random, NumPy, and PyTorch

   Use random.seed(), np.random.seed(), and torch.manual_seed() with the same value.

2. Step 2: Enable deterministic algorithms in PyTorch

   Use torch.use_deterministic_algorithms(True) to disable nondeterministic ops.

3. Final Answer:

   import random import numpy as np import torch random.seed(123) np.random.seed(123) torch.manual_seed(123) torch.use_deterministic_algorithms(True) -> Option D

4. Quick Check:

   All seeds set + deterministic mode = full reproducibility [OK]

Hint: Set all seeds and enable deterministic mode in PyTorch [OK]

Common Mistakes:

• Using non-existent torch.set_deterministic method
• Assigning torch.deterministic instead of calling function
• Forgetting to enable deterministic algorithms in PyTorch