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LLMs are so-called Large Language Models. In Q1 2024 they are the chic.

LangChain

https://python.langchain.com/docs/get_started/introduction

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Today ( ), GPT-4 is the most sophisticated model on the mass market.

Prompt Engineering

“prompt” is an old IT term, which has its origins in the Mainframe era. It’s how REPL (Read Eval Print Loop) frontends for Shells (such as Bash, ZSH, KSH etc.) ask for human input. In the early days of Human Computer Interaction, a prompt was the only User Interface.

LLMs do not offer Graphical User Interfaces (GUIs) to the users. A prompt here however will not be defined in a programmatic language (such as Bash), or in a higher programming language such as Python. It will be defined in a language such as normal English, German, French, Hindi… Therefore, LLMs can be understood as enabler technologies, to bring computation into domains and institutions, where stringent engineering interfaces are too complex or time-consuming.

Prototyping environment

The following code is prototyped in Google Colab (which is a Jupyter Notebook service). This is relevant for the dependency management of the Python libraries.

Python libraries

Save this file as requirements.txt in the Colab working space, or if you are an experienced developer, in your development environment of choice.

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Introduction - OpenAI API

First task: define Quantum Physics for kids

In Jupyter / Colab you can install all Python packages like this:

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Code Block
languagepy
# !pip - installs the packages in the base environment
# pip - installs the packages in the virtual environment

API key management

I use a file named env (not .env, because of some issues with Colab)

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You may add further keys.

Instantiate the local connector

The following code starts a local connector which simply sends requests to the OpenAI service endpoint. This costs money.

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  • temperature refers to the “creativity” parameter. The higher, the more creative.

  • gpt-4 is the model name

Forward a query

Code Block
languagepy
from langchain.chains import LLMChain
from langchain.prompts import PromptTemplate
from langchain_openai import OpenAI

template = """Question: {question}

Answer: Let's keep the answer very short and so simple so that
 a child can understand it."""

prompt = PromptTemplate.from_template(template)

llm = OpenAI()

llm_chain = LLMChain(prompt=prompt, llm=llm)

# Define the question as a dictionary to match the expected input format
question_dict = {"question": "explain quantum mechanics in one sentence"}

# Invoke the chain with the question dictionary
output = llm_chain.invoke(question_dict)

print(output)

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  • this is correct, based on encyclopedic standards

  • this is not something a child could understand (warning)

    • is this even possible, with just words?

Second task: define Quantum Physics scientifically

Here we refine the prompt a little more:

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  • encyclopedic and linguistic

Third task: implement and document Softmax (Python)

Code Block
languagepy
from langchain_openai import ChatOpenAI
from langchain import PromptTemplate
from langchain.chains import LLMChain, SimpleSequentialChain

# Initialize the first ChatOpenAI model (gpt-4) with specific temperature
llm1 = ChatOpenAI(model='gpt-4', temperature=0.5)

# Define the first prompt template
prompt_template1 = PromptTemplate.from_template(
    template='You are an experienced scientist and Python programmer. Write a function that implements the concept of {concept}.'
)
# Create an LLMChain using the first model and the prompt template
chain1 = LLMChain(llm=llm1, prompt=prompt_template1)

# Initialize the second ChatOpenAI model (gpt-4-turbo) with specific temperature
llm2 = ChatOpenAI(model='gpt-4', temperature=1.2)

# Define the second prompt template
prompt_template2 = PromptTemplate.from_template(
    template='Given the Python function {function}, describe it as detailed as possible.'
)
# Create another LLMChain using the second model and the prompt template
chain2 = LLMChain(llm=llm2, prompt=prompt_template2)

# Combine both chains into a SimpleSequentialChain
overall_chain = SimpleSequentialChain(chains=[chain1, chain2], verbose=True)

# Invoke the overall chain with the concept "linear regression"
output = overall_chain.invoke('softmax')

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Code Block
languagepy
> Entering new SimpleSequentialChain chain...
Sure, here is a Python function that implements the concept of softmax:

```python
import numpy as np

def softmax(x):
    """Compute softmax values for each sets of scores in x."""
    e_x = np.exp(x - np.max(x))
    return e_x / e_x.sum(axis=0)

# Test with some data
scores = [3.0, 1.0, 0.2]
print(softmax(scores))
```

This function takes as input a list of numbers (x) and returns a list of the same length where each value is the softmax of the corresponding input value. The softmax function is often used in machine learning, to convert a vector of real numbers into a probability distribution. Each output value is between 0 and 1 (inclusive), and the sum of all output values is 1.
The given Python function named `softmax` is used to compute the softmax values for each set of scores in `x`. The 'softmax' function applies the Softmax transformation/normalization to an input which results in continuous normalized probabilities for multi-class classification problems, typically used in the last operation of a machine learning model, such as a neural network  

The steps involved in the function are as follows:

1. First we import numpy, a popular python library that supports large multidimensional arrays and many high-level mathematical functions to operate on these arrays.

2. Define the `softmax` function which expects a list of numbers, denoted `x` as an argument.

3. Inside the function, the function `np.exp(x - np.max(x))` is used. The `np.exp()` function from the NumPy library stands for exponential. Thus, for each score `x` in the list `x`, we subtract the maximum element present in `x` to prevent overflow. With `np.exp(x)`, we are applying the exponential (exp) functionality to each of the entries in the sequence of values.

4. Then, the output (a new list of exponential values) is then divided by the sum of this output list (computed with `e_x.sum(axis=0)`), ensuring that the sum of all probabilities is 1. The `axis=0` refers to the column axis. This process effectively generates probabilities from a list of numbers.

The function usage is demonstrated by defining a list of raw scores, `[3.0, 1.0, 0.2]`. We pass this list to the `softmax` function and print the result. 

Finally, this Python function converts a vector/array/list of raw scores into a probabilistic form- making it suitable for multi-class classification problems. Larger scores reflect higher probability. 

All the scores returned in the list by the `softmax` function ranges between `0` and `1`, such sums to `1`. This helps emphasizes the highest values and suppress values one of which are significantly below the maximum values.

> Finished chain.

Again, this is correct.

Fourth task: generate Python code, and debug it

Code Block
from langchain import hub
from langchain.agents import AgentExecutor
from langchain_experimental.tools import PythonREPLTool

tools = [PythonREPLTool()]

from langchain.agents import create_openai_functions_agent
from langchain_openai import ChatOpenAI

instructions = """You are an agent designed to write and execute python code to answer questions.
You have access to a python REPL, which you can use to execute python code.
If you get an error, debug your code and try again.
Only use the output of your code to answer the question. 
You might know the answer without running any code, but you should still run the code to get the answer.
If it does not seem like you can write code to answer the question, just return "I don't know" as the answer.
"""
base_prompt = hub.pull("langchain-ai/openai-functions-template")
prompt = base_prompt.partial(instructions=instructions)

agent = create_openai_functions_agent(ChatOpenAI(temperature=0), tools, prompt)
agent_executor = AgentExecutor(agent=agent, tools=tools, verbose=True)
agent_executor.invoke({"input": "What is the 8th digit of Pi?"})

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  • This has been executed in the environment (warning)

Sandbox environments for LLM agents

Sandboxing here means that the changes to the environments are not persistent. There are various definitions of the term, including some which only apply in the context of software security and runtime environments. Here it is simply referring to a playground, where the LLM agents can freely roam.

Keep in mind: LLMs may hallucinate / are as smart as 🦜 . The need a cage.

Google Colab (throw-away environments)

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Easy, for Windows:

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Intermediate, for Docker (incl. Windows as a VM with Docker Desktop):

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