Home Machine Learning How does temperature affect subsequent token prediction in LLMs? | by Ankur Manikandan | Might, 2024

How does temperature affect subsequent token prediction in LLMs? | by Ankur Manikandan | Might, 2024

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How does temperature affect subsequent token prediction in LLMs? | by Ankur Manikandan | Might, 2024

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Introduction
Giant Language Fashions (LLMs) are versatile generative fashions suited to a wide selection of duties. They’ll produce constant, repeatable outputs or generate inventive content material by putting unlikely phrases collectively. The “temperature” setting permits customers to fine-tune the mannequin’s output, controlling the diploma of predictability.

Let’s take a hypothetical instance to grasp the affect of temperature on the subsequent token prediction.

We requested an LLM to finish the sentence, “It is a fantastic _____.” Let’s assume the potential candidate tokens are:

|   token    | logit |
|------------|-------|
| day | 40 |
| house | 4 |
| furnishings | 2 |
| expertise | 35 |
| drawback | 25 |
| problem | 15 |

The logits are handed by means of a softmax perform in order that the sum of the values is the same as one. Basically, the softmax perform generates chance estimates for every token.

Normal softmax perform

Let’s calculate the chance estimates in Python.

import numpy as np
import seaborn as sns
import pandas as pd
import matplotlib.pyplot as plt
from ipywidgets import interactive, FloatSlider

def softmax(logits):
exps = np.exp(logits)
return exps / np.sum(exps)

information = {
"tokens": ["day", "space", "furniture", "experience", "problem", "challenge"],
"logits": [5, 2.2, 2.0, 4.5, 3.0, 2.7]
}
df = pd.DataFrame(information)
df['probabilities'] = softmax(df['logits'].values)
df

| No. |   tokens   | logits | possibilities |
|-----|------------|--------|---------------|
| 0 | day | 5.0 | 0.512106 |
| 1 | house | 2.2 | 0.031141 |
| 2 | furnishings | 2.0 | 0.025496 |
| 3 | expertise | 4.5 | 0.310608 |
| 4 | drawback | 3.0 | 0.069306 |
| 5 | problem | 2.7 | 0.051343 |
ax = sns.barplot(x="tokens", y="possibilities", information=df)
ax.set_title('Softmax Chance Estimates')
ax.set_ylabel('Chance')
ax.set_xlabel('Tokens')
plt.xticks(rotation=45)
for bar in ax.patches:
ax.textual content(bar.get_x() + bar.get_width() / 2, bar.get_height(), f'{bar.get_height():.2f}',
ha='heart', va='backside', fontsize=10, rotation=0)
plt.present()

The softmax perform with temperature is outlined as follows:

the place (T) is the temperature, (x_i) is the (i)-th part of the enter vector (logits), and (n) is the variety of parts within the vector.

def softmax_with_temperature(logits, temperature):
if temperature <= 0:
temperature = 1e-10 # Stop division by zero or destructive temperatures
scaled_logits = logits / temperature
exps = np.exp(scaled_logits - np.max(scaled_logits)) # Numerical stability enchancment
return exps / np.sum(exps)

def plot_interactive_softmax(temperature):
possibilities = softmax_with_temperature(df['logits'], temperature)
plt.determine(figsize=(10, 5))
bars = plt.bar(df['tokens'], possibilities, shade='blue')
plt.ylim(0, 1)
plt.title(f'Softmax Possibilities at Temperature = {temperature:.2f}')
plt.ylabel('Chance')
plt.xlabel('Tokens')
# Add textual content annotations
for bar, chance in zip(bars, possibilities):
yval = bar.get_height()
plt.textual content(bar.get_x() + bar.get_width()/2, yval, f"{chance:.2f}", ha='heart', va='backside', fontsize=10)
plt.present()

interactive_plot = interactive(plot_interactive_softmax, temperature=FloatSlider(worth=1, min=0, max=2, step=0.01, description='Temperature'))
interactive_plot

At T = 1,

At a temperature of 1, the chance values are the identical as these derived from the usual softmax perform.

At T > 1,

Elevating the temperature inflates the possibilities of the much less seemingly tokens, thereby broadening the vary of potential candidates (or range) for the mannequin’s subsequent token prediction.

At T < 1,

Decreasing the temperature, then again, makes the chance of the most probably token method 1.0, boosting the mannequin’s confidence. Lowering the temperature successfully eliminates the uncertainty throughout the mannequin.

Conclusion

LLMs leverage the temperature parameter to supply flexibility of their predictions. The mannequin behaves predictably at a temperature of 1, carefully following the unique softmax distribution. Rising the temperature introduces higher range, amplifying much less seemingly tokens. Conversely, reducing the temperature makes the predictions extra centered, rising the mannequin’s confidence in probably the most possible token by decreasing uncertainty. This adaptability permits customers to tailor LLM outputs to a wide selection of duties, placing a stability between inventive exploration and deterministic output.

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