=Paper= {{Paper |id=Vol-3625/paper5 |storemode=property |title= Automatically Designing Machine Learning Models out of Natural Language |pdfUrl=https://ceur-ws.org/Vol-3625/paper5.pdf |volume=Vol-3625 |authors=Ernesto Luis Estevanell Valladares |dblpUrl=https://dblp.org/rec/conf/sepln/Valladares23 }} == Automatically Designing Machine Learning Models out of Natural Language== https://ceur-ws.org/Vol-3625/paper5.pdf
                                Automatically Designing Machine Learning Models
                                out of Natural Language
                                Ernesto Luis Estevanell-Valladares1,2
                                1
                                    Department of Software and Computer Systems, University of Alicante
                                2
                                    Faculty of Mathematics and Computer Science, University of Havana


                                                                         Abstract
                                                                         The popularity of artificial intelligence has led to an increasing need for machine learning models
                                                                         tailored to specific needs. AutoML aims to automate the process of creating effective machine-learning
                                                                         solutions, but current systems need to be more versatile to meet the demand. While more flexible and
                                                                         extensible heterogeneous systems have overcome many limitations of traditional AutoML systems, they
                                                                         lack accessibility due to their programmatic interfaces. We propose a research project to address this
                                                                         issue to develop a heterogeneous AutoML system that can produce optimal machine-learning pipelines
                                                                         using a natural language interface.

                                                                         Keywords
                                                                         AutoML, Natural Language Processing, Large Language Models.




                                1. Introduction
                                Machine learning has expanded rapidly, presenting researchers and practitioners with many
                                new algorithms and data sets. However, selecting the most suitable strategy for a given issue
                                has become increasingly complex, requiring extensive experimentation and technical expertise.
                                AutoML has emerged as a solution to this problem by providing powerful tools to search through
                                large machine-learning pipelines [1]. Nevertheless, the range of possible techniques for natural
                                language processing is vast, making it hard to combine and compare different algorithms. Thus,
                                AutoML algorithms must agree on a standard protocol for sharing outputs as inputs for any
                                other algorithm.
                                   To achieve the primary goal of AutoML, the systems must have interfaces that are easy to
                                use for those with limited computer science and machine learning knowledge. Furthermore,
                                the systems should have strong generalization capabilities to create tools that can be utilized in
                                various scenarios and produce machine learning models that can be applied to a wide range
                                of applications. However, current AutoML systems focus on a specific set of algorithms, often
                                tailored to a library or toolkit [2, 3, 4]. This reduces their ability to explore various algorithms
                                from different domains and find optimal solutions to complex, multifaceted problems. In
                                contrast, Heterogeneous AutoML systems generate learning solutions by mixing techniques
                                from different domains [5]. However, they do not provide natural interfaces for novice users

                                Doctoral Symposium on Natural Language Processing from the Proyecto ILENIA, 28 September 2023, Jaén, Spain.
                                $ elev1@alu.ua.es (E. L. Estevanell-Valladares)
                                 0000-0002-1168-1767 (E. L. Estevanell-Valladares)
                                                                       © 2022 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
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in programming or AutoML, and their execution requires preparation of the environment, the
definition of the problem in appropriate terms, and the provision of data in specific formats [2,
3, 4, 6, 7, 8, 9].
   Using natural language as a user interface can significantly enhance the accessibility and
user-friendliness of AutoML. Large Language Models (LLMs) are trendy for their ability to
process raw text and effectively identify patterns and connections in data [10, 11]. However,
these models can sometimes generate incorrect responses or need help with inference tasks
[12]. Recent studies suggest that incorporating external knowledge significantly improves the
performance of LLMs [13].
   Researchers are exploring combining these techniques to address the limitations of both
AutoML and LLMs. Shen et al. [14] employed an LLM to process queries and generate learning
task planning using pre-trained models. This approach has successfully integrated image, audio,
and text prediction, classification, and processing capabilities into a single system. However,
it does not focus on optimizing model selection or hyperparameter optimization. It does not
produce tuned learning models in standalone programs or allow for the export of inference
power to arbitrary environments.
   The research project consists of producing a Heterogeneous AutoML system that integrates
natural language processing as its primary interface. The ultimate goal is to design a tool to
generate optimal machine learning models that are flexible and adaptable to different contexts
and heterogeneous situations. This leads to our Main Research Question: ”In what way can
we integrate Natural Language into a Heterogeneous AutoML process?”.


2. Related Work
Most AutoML systems only use limited algorithms specific to a particular library or toolkit.
This limitation hinders their ability to solve complex problems by exploring various algorithms
from different areas. On the other hand, Heterogeneous AutoML systems combine techniques
from multiple domains to create better learning solutions. However, they require a user-friendly
interface for those new to programming or AutoML. This setup involves defining the problem
correctly, providing data in specific formats, and setting up the environment.
   Table 1 contrasts several existing AutoML systems with the system proposed in this research
regarding their capabilities of dealing with heterogeneous scenarios. This evaluation focused
on their capacity to handle diverse scenarios encompassing multiple algorithms. It is worth
noting that this assessment was solely based on their ability to handle heterogeneous algorithms
without consideration for their overall performance, capacity, or applicability.
   AutoML systems vary in capabilities and limitations, depending on the specific learning
libraries they are built on. Some, like Auto-Sklearn [3], Auto-Weka [4], and Auto-Keras[2], are
restricted to using Scikit-learn [15], Weka [16], and Keras [17], respectively. Other systems,
such as RECIPE [9] and Hyperopt [7], can incorporate algorithms from different libraries but
require a concrete implementation. TPOT [6] and ML-Plan [8] provide a more flexible approach,
combining technologies from multiple learning libraries to create concrete implementations of
learning pipelines. AutoML systems are mostly focused on supervised learning, but some offer
the potential to integrate unsupervised learning functionality, like Hyperopt.
                                                            Multiple ML problems




                                                                                                                Automatic Discovery




                                                                                                                                                                     Deployable Pipelines
                                       Multiple libraries




                                                                                                                                      Multiobjective
                                                                                   Probabilistic




                                                                                                                                                       Distributed
                                                                                                   Extensible
                 AutoML Systems                                                                                                                                                             Year
                 Hyperopt               ≈                                          ✓               ✓                                   ✓               ✓              ✓                     2013
                 Auto-Weka 2.0                                                     ✓               ✓                                                   ✓              ✓                     2017
                 RECIPE                 ≈                                                                                              ≈                                                    2017
                 TPOT                   ✓                                                                                              ✓                              ✓                     2018
                 ML-Plan                ✓                    ✓                                     ✓              ✓                    ✓               ✓                                    2018
                 Auto-Keras                                                        ✓               ✓                                   ✓                              ✓                     2019
                 Auto-Sklearn 2.0                                                  ✓               ✓                                   ✓               ✓              ✓                     2020
                 AutoGOAL               ✓                    ✓                     ✓               ✓              ✓                    ✓               ✓              ✓                     2023

Table 1
Comparison of several existing AutoML systems’ capabilities to deal with heterogeneous machine
learning problems. Entries marked with ≈ indicate that the system design enables the given capability,
but we have no record of its implementation.


   Systems like Auto-Sklearn and Auto-Keras benefit from a unified underlying API, while
modularly designed systems such as ML-Plan allow the addition and modification of algorithms.
Several systems allow balancing different objectives or metrics during optimization, which is
relevant in multiple development and research scenarios. For example, Auto-Keras and ML-Plan
use a weighted sum approach to combine multiple evaluation metrics into a single objective
function. These systems allow you to specify both the metrics and the weights assigned to each
metric, which allows you to control their relative importance in the optimization process.
   Hyperopt, ML-Plan, Auto-WEKA, and Auto-Sklearn include mechanisms to distribute search
processes and resources among multiple computers, optimizing search time and generating
learning pipelines more quickly. To meet the goal of AutoML, system solutions should be easily
usable in arbitrary environments and applicable as portable machine learning algorithms outside
the AutoML context. Systems such as Hyperopt, TPOT, and Auto-Sklearn allow exporting the
best pipeline found during the search process as a Python script, while Auto-WEKA can export
to JAVA [18] code. Auto-Keras allows exporting the models in various formats, including
TensorFlow [19], PyTorch [20], and Keras [17].
   Using probabilistic models to describe the space of possible pipelines is another interesting
feature of AutoML systems. AutoML systems based on Bayesian optimization build an internal
representation of the space of possible algorithm pipelines, which can be interpreted as assigning
a probability distribution to each particular pipeline. This feature describes the algorithm
pipeline space and allows researchers to gather additional information by analyzing which
regions have higher or lower probabilities of generating effective Pipeline components and
allow researchers to gather additional information.
   Previous research addressed the limitations of AutoML systems. Estevez-Velarde et al. [21]
introduced the concept of Heterogeneous AutoML, a more general formulation of the AutoML
Problem. Additionally, they introduced AutoGOAL, a flexible and efficient system for het-
erogeneous AutoML implemented in Python. With AutoGOAL, users can describe a specific
machine problem, input and output requirements, and a set of objectives. The system then
automatically finds the best pipeline of algorithms from various libraries, including Scikit-learn
[15], NLTK [22], Keras [17], and Gensim [23]. It is also customizable, allowing users to add and
integrate new algorithms into the existing pipelines. AutoGOAL uses a Pareto Front approach
to multiobjective optimization and an optimization process based on probabilistic grammatical
evolution for context-free grammar [24].


3. Proposed Research
AutoGOAL has achieved state-of-the-art performance against other AutoML systems and has
been able to solve machine-learning tasks outside of supervised learning. Additionally, it can
build complex pipelines targeting difficult NLP tasks like Named Entity Recognition, being
able to connect algorithms of different natures. This research project will use AutoGOAL as a
baseline for its capabilities regarding Heterogeneous AutoML.

3.1. Heterogeneous AutoML
According to Estevez-Velarde et al. [21], the Heterogeneous AutoML problem’s space of all
possible pipelines can be represented as a 𝐺𝐴 graph. This graph consists of nodes representing
each known algorithm 𝑎𝑖 , and edges exist between all pairs 𝑎𝑖 , 𝑎𝑗 such that their corresponding
output and input types are compatible. Given a machine-learning task defined as a function
that transforms an input type into an output type, we can build a specific search space graph
𝐺′𝐴 that only models valid pipelines. To extract 𝐺′𝐴 , we must introduce two additional nodes to
𝐺𝐴 : Input and Output. These nodes are then connected to all algorithms capable of producing
the desired output from the specific input. By identifying any path in 𝐺′𝐴 that connects the
Input and Output nodes, we can obtain a pipeline that addresses the machine-learning problem
at hand.
   A suitable computational implementation of this process requires solving the following
problems:
   1. Defining each algorithm and their respective input and output, such that it is compu-
      tationally feasible to determine if two algorithms can be connected and construct the
      graph.
   2. Designing an optimization strategy that can effectively search in the space of all pipelines,
      algorithms, and their hyperparameters, given restricted computational resources.
   AutoGOAL utilizes a set of Semantic Type objects to implement this compatibility function.
Each semantic data type is a Python class that belongs to a hierarchy in which object inheritance
directly represents the relation for type compatibility (e.g., Word can also be interpreted as
Text, a more general type). The data types have a semantic interpretation beyond their
underlying computational structure. For example, a string in computational terms can either
be a Document, a Sentence, or a Word. Each algorithm is implemented as a class with a
run(input: Tin) -> Tout method that performs the corresponding processing, potentially
wrapping an underlying implementation from a machine learning library. Each algorithm’s
input and output types are specified using Semantic Types and represented by the Tin and
Tout annotations.
   While this method for computing compatibility has advantages, it is rigid and difficult to
maintain. Due to the closed nature of the type system, precise type definitions must be matched
for any new algorithms identified and added to the AutoGOAL search space. Also, because
adding new Semantic Types does not automatically update current algorithm annotations, users
need to check on every existing algorithm to identify which should be annotated accordingly.
Moreover, this mechanism assumes a tree-like structure of type compatibility when there might
be more complex relationships (e.g., a Stem might also be considered a Word, albeit these two
types do not inherit from each other). This leads to an interesting question: ”Can we model
algorithm compatibility more openly?”.
   Recent proposals suggest using natural language to store information describing algorithms.
Shen et al. [14] uses Jsons, mainly text-based, to store information about pre-trained models.
They parse natural language prompts into multiple tasks that are matched with suitable algo-
rithms using an LLM. However, this tool does not address the AutoML problem, as it does not
optimize model selection or hyperparameter configurations for algorithms. In contrast, Zhang
et al. [25] aims to develop an AutoML system called AutoML-GPT, which uses LLMs to train
models on datasets with user inputs and descriptions automatically. The LLMs serve as an
automatic training system to establish connections with models and process inputs.

3.2. Research Questions
In this research, we propose the integration of description cards based on text data for algorithms
in AutoGOAL. By leveraging the power of LLMs, we can match algorithms based on their
description. This method adds a vital factor of generalization that might solve the previous
limitations of AutoGOAL. Moreover, by substituting the current Semantic Type system with
natural language, we open the tool’s interface to accept user text prompts.
   To achieve our main objective, we must address various questions within the proposal:

   1. Which LLM should we use?
   2. What language should we support in the interface?
   3. What machine learning tasks should we target?

   To answer the first question, we must conduct experiments to determine which LLM will be
most suitable for our project. One idea is to use two different LLMs that are each fine-tuned
for specific purposes. For example, one LLM can help determine the compatibility between
algorithms used during the optimization process. At the same time, the other can identify
problem definitions (input and output types and objective functions) out of natural language
for better user interaction with the system.
   For the second question, we aim to develop an interface not tailored to a specific language to
make it fully inclusive. However, the performance of LLMs can vary significantly in different
languages due to differences in available training data. Therefore, we will compare the perfor-
mance of multilingual models against specific-language models in our objective tasks before
deciding which approach to follow.
   Finally, our main objective is to extend existing tools, specifically AutoGOAL, to saturate
the definition of Heterogeneous AutoML, thus achieving more flexibility and integrating more
tasks seamlessly. We can achieve this by using the compatibility function to discover algorithms
that were once bound to a specific machine-learning problem but can be part of the solution of
another one. The diversity and amount of algorithms determine the limit of tasks we can solve
in the system.
   The proposed system has valuable scientific, economic, and social implications. It can enhance
our understanding of artificial intelligence and apply it to robotics and process automation.
Economically, it can speed up the development of applications and decrease the cost and time
required for building machine learning solutions.
   From a social standpoint, an AutoML system based on natural language can improve the
accessibility and ease of use of machine learning, especially in critical areas such as healthcare
and education. Furthermore, automating the building of learning models can lessen the need
for human intervention in repetitive and monotonous tasks, thus reducing the carbon footprint
associated with computer system operations.


4. Proposed Experimentation
To evaluate the potential of our proposed system, we plan to develop a benchmark that incorpo-
rates challenging tasks from multiple domains such as vision, NLP, audio, and others. We will
perform ablation studies to comprehend the significance of different LLMs and optimization
strategies in the overall performance of our system. In addition, to make the evaluation more
comprehensive, we will compare our new system with its previous version and other state-
of-the-art AutoML systems. By providing more flexibility, we aim to test the capabilities of
our system against human adversaries in various challenges. Furthermore, we will explore the
possibility of integrating human feedback into the learning process, which can provide valuable
insights and lead to further improvement.


5. Conclusions and Future work
The purpose of this publication is to present the research framework for a thesis that aims to
investigate the intersection between AutoML and Large Language Models (LLMs). Our objective
is to improve AutoML systems, making them more accessible, user-friendly, and versatile. In
order to achieve this goal, we will begin by examining the current state of the art in this field.
Subsequently, we will develop corresponding description cards for each algorithm available
in AutoGOAL and also include new algorithms, such as pre-trained models from Hugging
Face along with their respective cards. The next step will be integrating an LLM to model the
compatibility function between algorithms, thereby enabling a natural language interface for
user interaction. Ultimately, our aim is to pave the way for more inclusive and efficient machine
learning applications in various domains.
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