Data Science

🐍 Mastering Temperature And Top_p In Python Language Models That Will Transform Your Python Developer!

Hey there! Ready to dive into Mastering Temperature And Top_p In Python Language Models? This friendly guide will walk you through everything step-by-step with easy-to-follow examples. Perfect for beginners and pros alike!

SuperML Team
Share this article

Share:

🚀

💡 Pro tip: This is one of those techniques that will make you look like a data science wizard! Understanding Temperature and Top_p in Language Models - Made Simple!

Temperature and top_p are crucial parameters in language models that control the randomness and diversity of generated text. These settings affect how the model selects the next token in a sequence, influencing the creativity and coherence of the output.

Don’t worry, this is easier than it looks! Here’s how we can tackle this:

import torch
import torch.nn.functional as F

def sample_with_temperature(logits, temperature=1.0):
    # Apply temperature scaling
    scaled_logits = logits / temperature
    # Convert to probabilities
    probs = F.softmax(scaled_logits, dim=-1)
    # Sample from the distribution
    return torch.multinomial(probs, num_samples=1)

# Example logits
logits = torch.tensor([1.0, 2.0, 3.0, 4.0])
# Sample with different temperatures
low_temp = sample_with_temperature(logits, temperature=0.5)
high_temp = sample_with_temperature(logits, temperature=2.0)

print(f"Low temperature (0.5) sample: {low_temp.item()}")
print(f"High temperature (2.0) sample: {high_temp.item()}")

🚀

🎉 You’re doing great! This concept might seem tricky at first, but you’ve got this! Temperature in Language Models - Made Simple!

Temperature is a hyperparameter that controls the randomness of predictions by scaling the logits before applying softmax. A lower temperature makes the model more confident and deterministic, while a higher temperature increases randomness and creativity.

Let’s break this down together! Here’s how we can tackle this:

import numpy as np
import matplotlib.pyplot as plt

def apply_temperature(logits, temperature):
    return np.exp(logits / temperature) / np.sum(np.exp(logits / temperature))

logits = np.array([1, 2, 3, 4, 5])
temperatures = [0.1, 0.5, 1.0, 2.0]

plt.figure(figsize=(12, 6))
for temp in temperatures:
    probs = apply_temperature(logits, temp)
    plt.plot(probs, label=f"T={temp}")

plt.title("Effect of Temperature on Token Probabilities")
plt.xlabel("Token Index")
plt.ylabel("Probability")
plt.legend()
plt.show()

🚀

Cool fact: Many professional data scientists use this exact approach in their daily work! Implementing Temperature in Token Selection - Made Simple!

Here’s how to implement temperature-based token selection in Python. This process involves scaling the logits, converting them to probabilities, and then sampling from the resulting distribution.

This next part is really neat! Here’s how we can tackle this:

import numpy as np

def sample_with_temperature(logits, temperature=1.0):
    # Scale logits by temperature
    scaled_logits = logits / temperature
    # Convert to probabilities
    probs = np.exp(scaled_logits) / np.sum(np.exp(scaled_logits))
    # Sample from the distribution
    return np.random.choice(len(logits), p=probs)

# Example usage
logits = np.array([1, 2, 3, 4, 5])
selected_token = sample_with_temperature(logits, temperature=0.5)
print(f"Selected token index: {selected_token}")

🚀

🔥 Level up: Once you master this, you’ll be solving problems like a pro! Top_p Sampling (Nucleus Sampling) - Made Simple!

Top_p sampling, also known as nucleus sampling, is an alternative to temperature-based sampling. It selects from the smallest possible set of tokens whose cumulative probability exceeds the probability p. This method helps maintain diversity while avoiding low-probability tokens.

Let me walk you through this step by step! Here’s how we can tackle this:

import numpy as np

def top_p_sampling(logits, p=0.9):
    # Sort the logits in descending order
    sorted_logits = np.sort(logits)[::-1]
    sorted_indices = np.argsort(logits)[::-1]
    
    # Calculate cumulative probabilities
    cumulative_probs = np.cumsum(sorted_logits)
    
    # Find the index where cumulative probability exceeds p
    last_index = np.where(cumulative_probs > p)[0][0]
    
    # Create a mask for the selected tokens
    mask = np.zeros_like(logits, dtype=bool)
    mask[sorted_indices[:last_index+1]] = True
    
    # Set the probabilities of unselected tokens to 0
    logits[~mask] = float('-inf')
    
    # Convert to probabilities and sample
    probs = np.exp(logits) / np.sum(np.exp(logits))
    return np.random.choice(len(logits), p=probs)

# Example usage
logits = np.array([1, 2, 3, 4, 5])
selected_token = top_p_sampling(logits, p=0.9)
print(f"Selected token index: {selected_token}")

🚀 Comparing Temperature and Top_p - Made Simple!

Both temperature and top_p affect the diversity of generated text, but they work differently. Temperature scales the entire distribution, while top_p truncates it. Let’s compare their effects on a simple probability distribution.

This next part is really neat! Here’s how we can tackle this:

import numpy as np
import matplotlib.pyplot as plt

def apply_temperature(logits, temperature):
    return np.exp(logits / temperature) / np.sum(np.exp(logits / temperature))

def apply_top_p(probs, p):
    sorted_probs = np.sort(probs)[::-1]
    cumulative_probs = np.cumsum(sorted_probs)
    cutoff = np.where(cumulative_probs > p)[0][0]
    probs[probs < sorted_probs[cutoff]] = 0
    return probs / np.sum(probs)

logits = np.array([1, 2, 3, 4, 5])
base_probs = np.exp(logits) / np.sum(np.exp(logits))

plt.figure(figsize=(12, 6))
plt.plot(base_probs, label="Original")
plt.plot(apply_temperature(logits, 0.5), label="Temperature=0.5")
plt.plot(apply_top_p(base_probs.(), 0.9), label="Top_p=0.9")

plt.title("Comparison of Temperature and Top_p Sampling")
plt.xlabel("Token Index")
plt.ylabel("Probability")
plt.legend()
plt.show()

🚀 Real-Life Example: Text Generation - Made Simple!

Let’s look at how temperature and top_p affect text generation in a simple language model. We’ll use a pre-trained model to generate text with different settings.

Let me walk you through this step by step! Here’s how we can tackle this:

from transformers import GPT2LMHeadModel, GPT2Tokenizer

def generate_text(prompt, max_length, temperature=1.0, top_p=1.0):
    model = GPT2LMHeadModel.from_pretrained('gpt2')
    tokenizer = GPT2Tokenizer.from_pretrained('gpt2')
    
    input_ids = tokenizer.encode(prompt, return_tensors='pt')
    
    output = model.generate(
        input_ids,
        max_length=max_length,
        temperature=temperature,
        top_p=top_p,
        do_sample=True,
        num_return_sequences=1
    )
    
    return tokenizer.decode(output[0], skip_special_tokens=True)

prompt = "The future of artificial intelligence is"
print("Temperature 0.7:")
print(generate_text(prompt, 50, temperature=0.7))
print("\nTop_p 0.9:")
print(generate_text(prompt, 50, temperature=1.0, top_p=0.9))

🚀 Visualizing Token Probabilities - Made Simple!

To better understand how temperature and top_p affect token selection, let’s visualize the probability distribution for the next token in a sequence.

Let’s break this down together! Here’s how we can tackle this:

import numpy as np
import matplotlib.pyplot as plt

def get_token_probs(logits, temperature=1.0, top_p=1.0):
    probs = np.exp(logits / temperature) / np.sum(np.exp(logits / temperature))
    if top_p < 1.0:
        sorted_probs = np.sort(probs)[::-1]
        cumulative_probs = np.cumsum(sorted_probs)
        cutoff = np.where(cumulative_probs > top_p)[0][0]
        probs[probs < sorted_probs[cutoff]] = 0
        probs = probs / np.sum(probs)
    return probs

logits = np.array([1, 2, 3, 4, 5, 4, 3, 2, 1])
tokens = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']

plt.figure(figsize=(12, 6))
plt.bar(tokens, get_token_probs(logits), alpha=0.5, label='Original')
plt.bar(tokens, get_token_probs(logits, temperature=0.5), alpha=0.5, label='Temperature=0.5')
plt.bar(tokens, get_token_probs(logits, top_p=0.9), alpha=0.5, label='Top_p=0.9')

plt.title("Token Probabilities with Different Sampling Methods")
plt.xlabel("Tokens")
plt.ylabel("Probability")
plt.legend()
plt.show()

🚀 Temperature and Creativity - Made Simple!

Temperature can be used to control the creativity and randomness of generated text. Let’s experiment with different temperature values to see how they affect the output of a simple text generation model.

Here’s a handy trick you’ll love! Here’s how we can tackle this:

import random

def simple_text_generator(prompt, length, temperature):
    vocabulary = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
    generated_text = prompt
    
    for _ in range(length):
        # Simple "logits" based on the last character
        logits = [ord(c) for c in vocabulary]
        logits = [l + (ord(generated_text[-1]) - l) * 0.1 for l in logits]
        
        # Apply temperature
        probs = [np.exp(l / temperature) for l in logits]
        probs = [p / sum(probs) for p in probs]
        
        # Sample next character
        next_char = random.choices(vocabulary, weights=probs)[0]
        generated_text += next_char
    
    return generated_text

prompt = "THE QUICK BROWN FOX "
temperatures = [0.1, 0.5, 1.0, 2.0]

for temp in temperatures:
    print(f"Temperature {temp}:")
    print(simple_text_generator(prompt, 50, temp))
    print()

🚀 Top_p and Coherence - Made Simple!

Top_p sampling can help maintain coherence in generated text by focusing on the most likely tokens. Let’s implement a simple top_p sampling function and see how it affects text generation.

Here’s a handy trick you’ll love! Here’s how we can tackle this:

import random

def top_p_sampling(probs, p):
    sorted_probs = sorted(probs, reverse=True)
    cumulative_probs = np.cumsum(sorted_probs)
    cutoff = next(i for i, cp in enumerate(cumulative_probs) if cp > p)
    top_p_probs = [p if p >= sorted_probs[cutoff] else 0 for p in probs]
    return [p / sum(top_p_probs) for p in top_p_probs]

def simple_text_generator_top_p(prompt, length, p):
    vocabulary = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
    generated_text = prompt
    
    for _ in range(length):
        # Simple "logits" based on the last character
        logits = [ord(c) for c in vocabulary]
        logits = [l + (ord(generated_text[-1]) - l) * 0.1 for l in logits]
        
        # Convert to probabilities and apply top_p
        probs = [np.exp(l) for l in logits]
        probs = [p / sum(probs) for p in probs]
        probs = top_p_sampling(probs, p)
        
        # Sample next character
        next_char = random.choices(vocabulary, weights=probs)[0]
        generated_text += next_char
    
    return generated_text

prompt = "THE QUICK BROWN FOX "
p_values = [0.5, 0.9, 0.99]

for p in p_values:
    print(f"Top_p {p}:")
    print(simple_text_generator_top_p(prompt, 50, p))
    print()

🚀 Combining Temperature and Top_p - Made Simple!

In practice, it’s common to use both temperature and top_p sampling together. This combination can provide fine-grained control over the trade-off between creativity and coherence in generated text.

This next part is really neat! Here’s how we can tackle this:

def combined_sampling(logits, temperature, top_p):
    # Apply temperature
    scaled_logits = logits / temperature
    probs = np.exp(scaled_logits) / np.sum(np.exp(scaled_logits))
    
    # Apply top_p
    sorted_probs = np.sort(probs)[::-1]
    cumulative_probs = np.cumsum(sorted_probs)
    cutoff = np.where(cumulative_probs > top_p)[0][0]
    probs[probs < sorted_probs[cutoff]] = 0
    probs = probs / np.sum(probs)
    
    return np.random.choice(len(logits), p=probs)

# Example usage
logits = np.array([1, 2, 3, 4, 5])
temperature = 0.8
top_p = 0.9

selected_token = combined_sampling(logits, temperature, top_p)
print(f"Selected token index: {selected_token}")

🚀 Real-Life Example: Chatbot Responses - Made Simple!

Let’s implement a simple chatbot that uses temperature and top_p to generate responses. We’ll use different settings to show how they affect the chatbot’s personality.

Ready for some cool stuff? Here’s how we can tackle this:

import random

responses = {
    "greeting": ["Hello!", "Hi there!", "Greetings!", "Hey!", "Good day!"],
    "farewell": ["Goodbye!", "See you later!", "Bye!", "Take care!", "Until next time!"],
    "unknown": ["I'm not sure about that.", "Could you rephrase that?", "Interesting question!", "I'll have to think about that."]
}

def chatbot_response(input_text, temperature, top_p):
    input_lower = input_text.lower()
    if "hello" in input_lower or "hi" in input_lower:
        category = "greeting"
    elif "bye" in input_lower or "goodbye" in input_lower:
        category = "farewell"
    else:
        category = "unknown"
    
    logits = [random.random() for _ in responses[category]]
    probs = np.exp(logits) / np.sum(np.exp(logits))
    
    selected_index = combined_sampling(logits, temperature, top_p)
    return responses[category][selected_index]

print("Conservative Chatbot (Low temperature, high top_p):")
for _ in range(3):
    user_input = random.choice(["Hello", "What's the meaning of life?", "Goodbye"])
    print(f"User: {user_input}")
    print(f"Bot: {chatbot_response(user_input, temperature=0.5, top_p=0.9)}\n")

print("Creative Chatbot (High temperature, low top_p):")
for _ in range(3):
    user_input = random.choice(["Hello", "What's the meaning of life?", "Goodbye"])
    print(f"User: {user_input}")
    print(f"Bot: {chatbot_response(user_input, temperature=1.5, top_p=0.7)}\n")

🚀 Optimizing Temperature and Top_p - Made Simple!

Finding the right balance of temperature and top_p can significantly improve the quality of generated text. Let’s create a simple optimization function that tries different combinations and evaluates them based on a given metric.

Don’t worry, this is easier than it looks! Here’s how we can tackle this:

import numpy as np
from scipy.optimize import minimize

def text_quality_metric(text):
    # Placeholder metric: unique character ratio
    return len(set(text)) / len(text)

def generate_text(temperature, top_p):
    # Placeholder function to generate text
    # In practice, this would use a language model
    return "Sample generated text"

def optimize_params(initial_temp, initial_top_p):
    def objective(params):
        temp, top_p = params
        text = generate_text(temp, top_p)
        return -text_quality_metric(text)  # Negative for minimization

    result = minimize(
        objective,
        [initial_temp, initial_top_p],
        bounds=[(0.1, 2.0), (0.1, 1.0)],
        method='L-BFGS-B'
    )

    return result.x

optimal_temp, optimal_top_p = optimize_params(1.0, 0.9)
print(f"best temperature: {optimal_temp:.2f}")
print(f"best top_p: {optimal_top_p:.2f}")

🚀 Adaptive Temperature and Top_p - Made Simple!

In some scenarios, it’s beneficial to adjust temperature and top_p dynamically based on the context or the generated text so far. Let’s implement a simple adaptive mechanism.

Let’s make this super clear! Here’s how we can tackle this:

def adaptive_sampling(logits, base_temperature, base_top_p, context):
    # Adjust temperature based on context length
    adaptive_temp = base_temperature * (1 + len(context) * 0.01)
    
    # Adjust top_p based on unique token ratio in context
    unique_ratio = len(set(context)) / len(context)
    adaptive_top_p = base_top_p * (1 - unique_ratio * 0.2)
    
    # Apply combined sampling with adaptive parameters
    return combined_sampling(logits, adaptive_temp, adaptive_top_p)

# Example usage
context = "The quick brown fox jumps over the lazy dog"
logits = np.array([1, 2, 3, 4, 5])
base_temperature = 0.8
base_top_p = 0.9

selected_token = adaptive_sampling(logits, base_temperature, base_top_p, context)
print(f"Selected token index: {selected_token}")

🚀 Visualizing the Impact of Temperature and Top_p - Made Simple!

To better understand how temperature and top_p affect token selection, let’s create a heatmap visualization of token probabilities under different parameter combinations.

Here’s a handy trick you’ll love! Here’s how we can tackle this:

import numpy as np
import matplotlib.pyplot as plt

def token_probabilities(logits, temperature, top_p):
    probs = np.exp(logits / temperature) / np.sum(np.exp(logits / temperature))
    sorted_probs = np.sort(probs)[::-1]
    cumulative_probs = np.cumsum(sorted_probs)
    cutoff = np.where(cumulative_probs > top_p)[0][0] if top_p < 1.0 else len(probs)
    probs[probs < sorted_probs[cutoff]] = 0
    return probs / np.sum(probs)

logits = np.array([1, 2, 3, 4, 5])
temperatures = np.linspace(0.1, 2.0, 20)
top_ps = np.linspace(0.1, 1.0, 20)

heatmap_data = np.zeros((len(temperatures), len(top_ps)))

for i, temp in enumerate(temperatures):
    for j, p in enumerate(top_ps):
        probs = token_probabilities(logits, temp, p)
        heatmap_data[i, j] = np.max(probs)  # Use max probability as metric

plt.figure(figsize=(10, 8))
plt.imshow(heatmap_data, cmap='viridis', aspect='auto', origin='lower')
plt.colorbar(label='Max Token Probability')
plt.xlabel('Top_p')
plt.ylabel('Temperature')
plt.title('Impact of Temperature and Top_p on Token Probabilities')
plt.xticks(range(0, len(top_ps), 5), [f'{p:.1f}' for p in top_ps[::5]])
plt.yticks(range(0, len(temperatures), 5), [f'{t:.1f}' for t in temperatures[::5]])
plt.show()

🚀 Additional Resources - Made Simple!

For those interested in diving deeper into the topics of temperature and top_p sampling in language models, here are some valuable resources:

  1. “The Curious Case of Neural Text Degeneration” by Holtzman et al. (2019) ArXiv: https://arxiv.org/abs/1904.09751
  2. “How to Sample from Language Models” by Hugging Face https://huggingface.co/blog/how-to-generate
  3. “Language Models are Few-Shot Learners” by Brown et al. (2020) ArXiv: https://arxiv.org/abs/2005.14165

These resources provide in-depth discussions on sampling strategies, their effects on text generation, and their applications in various language models.

🎊 Awesome Work!

You’ve just learned some really powerful techniques! Don’t worry if everything doesn’t click immediately - that’s totally normal. The best way to master these concepts is to practice with your own data.

What’s next? Try implementing these examples with your own datasets. Start small, experiment, and most importantly, have fun with it! Remember, every data science expert started exactly where you are right now.

Keep coding, keep learning, and keep being awesome! 🚀

Back to Blog

Related Posts

View All Posts »