[AlphaCodium] Highest Performance Code Generation Method Specialized For Programming

Large Language Models 30/05/2024

3 main points
✔️ Proposed a code generation method called AlphaCodium
✔️ Code generation in a flow consisting of a preprocessing phase and an iteration phase
✔️Significant improvement incode generationcapability ofLLMs with AlphaCodium

Code Generation with AlphaCodium: From Prompt Engineering to Flow Engineering
written by Tal Ridnik,Dedy Kredo,Itamar Friedman
(Submitted on 16 Jan 2024)
Comments: Published on arxiv.
Subjects: Machine Learning (cs.LG); Computation and Language (cs.CL); Software Engineering (cs.SE)

code：

The images used in this article are from the paper, the introductory slides, or were created based on them.

Proposed code generation method called AlphaCodium

The content of this paper is"Improving the Code Generation Capability ofLLMs by a Technique Called AlphaCodium.

The key points of this study are as follows

Challenge: Existing optimization methods for natural language cannot stretch LLM code generation capabilities
Solution: Optimization using AlphaCodium, a "test-driven, multi-step code generation flow.
Point: AlphaCodium could improve GPT-4's ability to generate code.

In other words, AlphaCodium, a unique code generation method, was able to improve LLM's performance in the programming area.

Incidentally, AlphaCodium has succeeded in significantly improving code generation performance by using generic language models (GPT, DeepSeek, etc.) without additional training and applying dedicated flows.

This is a method that can be applied to a wide variety of language models without requiring additional data or a computationally expensive training phase.

Existing methods do not bring out the code generation capabilities of LLM

Recent large-scale language models (LLMs) perform very well in generating code for simple programming tasks. However, real-world programming is much more complex, and even recent LLMs often fail to get the point across.

This is because code generation tasks have unique challenges that differ from those of natural language processing, and optimization methods for natural language cannot be applied without modification.

Specifically, they have the following issues

Different programming languages have different grammar rules.
Minor mistakes cause grammatical errors.
Difficulty in properly handling exceptional situations such as incorrect entries
Difficulty in detailing problem statements described in natural language in the code
Difficult to address non-functional requirements such as time calculations and memory usage
Difficulty in proper selection and implementation of complex data structures and algorithms
Difficult to design with the awareness of working with multiple codes
Difficult to constrain the execution environment

So far, code generation has been done using "optimization methods for natural language tasks," which means that as tasks become more complex, they are more prone to errors.

Therefore, optimization methods specific to coding tasks have been studied to improve performance in more complex coding tasks.

Existing research

The release of the CodeContests dataset allows for the evaluation of models and methods for solving more difficult programming problems collected from competitive programming platforms.

In the earlier AlphaCode study, a large number of calculations were performed by fine tuning, which is not considered practical.

CodeChain also introduces a new inference framework.

AlphaCodium's specific flow

AlphaCodium's code generation process is divided into two main phases: the "pre-processing phase" and the "iteration phase.

The left side of the above figure is the pre-processing phase and the right side is the iterative phase.

Pretreatment Phase

In the pre-processing phase, analysis and inference are performed on problems specified in natural language. Specifically,thefollowing processing is performed

AI extracts goals, inputs, outputs, rules, constraints, etc. from the problem statement and itemizes them
Generates multiple candidate answer codes based on understanding of the question text
Rank the generated answer codes and select the best ones
Run validation tests on selected answer codes
Analyze results of validation tests and create additional test cases

In other words, the pre-processing phase uses natural language processing to analyze the problem, generate and select initial candidate solution codes, and prepare test cases for use in the iteration phase.

Below is an example of a given problem statement, whichincludes information such astaskgoals, inputs, outputs, rules, and constraints.

The information is then extracted from the above problem statement and summarized by the AI in bullet points as follows

Iteration phase

In the iterative phase, the solution code generated in the preprocessing phase is improved. Specifically,thefollowing cycle is repeated

The answer code selected in the pre-processing phase is used as the initial code.
Test initial code in "Public Test".
Analyze test results, modify and improve code
Re-test the improved code and adopt it if the results improve
Further iterative improvement with "additional AI-generated tests"
Re-test the improved code and adopt it if the results improve

In other words, during the iterative phase, the code is actually executed and the solution code is progressively improved using the test results as feedback. In addition to existing test data sets, the testing also utilizes additional AI-generated test sets, which allows for highly comprehensive verification.

Techniques for code generation tasks

When using AlphaCodium to generate code, the following techniques have been described as more effective

Use of structured output in YAML format
Semantic reasoning in bulleted form
Modular code generation
Soft decision-making through double validation
Leave room for exploration and avoid direct questions
test anchor

These methods are widely applicable not only to this study, but also to code generation tasks using LLMs in general.

Each technique is described in turn.

Use of structured output in YAML format

By requiring output in YAML format when designing prompts, complex tasks can be systematically represented, greatly reducing the effort of prompt engineering.

According to the authors, the YAML format is more suitable than JSON, especially for code generation tasks.

The generated code often contains single quotes, double quotes, and special characters, but it is difficult to place these characters effectively in JSON. On the other hand, with YAML, the block scalar format can correctly represent arbitrary text and code as long as proper indentation is observed.

The YAML format also requires fewer tokens than JSON because it does not require braces, quotation marks, or escape characters like JSON.

This will reduce cost and inference time and improve quality.

Semantic reasoning in bulleted form

When having them reason about a problem, they get better results by putting the output in a bulleted format. This is because the bulleted format encourages the LLM to gain a deeper understanding of the problem and improves the output.

Modular code generation

By instructing the code to be divided into multiple functions in detail, rather than generating a single function, the code will generate good quality code with fewer bugs.

Soft decision-making through double validation

Encourage LLMs to "reason critically" by having an additional step that asks them to re-generate the generated output and modify it as needed.

This is more effective, he said, than questions that require a direct "Yes or No" answer.

Leave room for exploration and avoid direct questions

Directly asking questions about complex issues often generates incorrect answers. Therefore, we adopt a flow that gradually accumulates data starting with simpler tasks. It is important to avoid irreversible decisions and to leave room for exploration and code iteration.

Test anchor

Because some AI-generated tests may be incorrect, use the verified tests in the public test set as an anchor to prevent accidental modification of the code.

Effectiveness of this method

Experimental Details

To test the effectiveness of the proposed method, we conduct experiments using CodeContests, a dataset of competitive programming problems.

This experiment evaluates the extent to which AlphaCodium improves LLM code generation performance compared to the direct prompt input method.

In addition, we evaluate AlphaCodium's performance in comparison to the prior studies AlphaCode and CodeChain.

Data-set

In this study, we evaluate AlphaCodium's performance using CodeContests, a dataset of competitive programming problems.

The main features of the CodeContests dataset are

Composed of questions collected from competition programming platforms
Long and complex natural language problem description
Approximately 200 private input/output tests available for each question
Includes 10,000 training data, 107 validation data, and 165 test data (no training set is used in this study, only validation and test sets)

As mentioned above, CodeContests is a good benchmark that consists of realistic and challenging questions that are specific to competitive programming.

Result

As mentioned earlier, the two experiments in this study are as follows

Direct prompt input vs. AlphaCodium
Prior research vs. AlphaCodium

Let's look at them in order.

Direct prompt input vs. AlphaCodium

Five codes are generated for each question and the percentage of correct answers (pass@5) is compared.

The results are as follows ("Direct" in the METHOD column = direct prompt input)

The results show that when using GPT-4, AlphaCodium improves the percentage of correct answers from 19% to 44% on the validation set (a 2.3-fold improvement).

Other models, such as GPT-3.5 and DeepSeek, also show consistent and significant improvements.

Previous studies vs. AlphaCodium

As before, 5 codes are generated for each question and the percentage of correct answers (pass@5) is compared.

The results are as follows

Results show that AlphaCodium outperforms CodeChain when using the same GPT-3.5 model.

Incidentally, AlphaCode performs fine tuning and a large amount of computation, whereas AlphaCodium uses LLM as-is without training. However, it can be seen that the AlphaCodium still achieves the same or better performance as AlphaCode with less than 1/10,000th of the computational complexity.

AlphaCodium significantly improves LLM code generation performance

This article introduced research on AlphaCodium, a new code generation method specifically designed for competition programming problems.

This is an important study that demonstrates a significant improvement in LLM code generation performance.

Three limitations of this study include the following three points

This method is specialized for competition programming problems and needs to be devised for application to actual development
Validation not only on CodeContests but also on other data sets is desired
This method is specific to code generation and its applicability to other tasks is unknown

Personal Opinion

I thought this research was an important achievement, as it was a method that was distinct from conventional prompt engineering and suggested the possibility of advanced code generation methods.

However, as mentioned in this paper, there is still room for improvement for use in actual development sites.

The project for this study is also available on GitHub for you to try.

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