19 research outputs found
HyperNCA: Growing Developmental Networks with Neural Cellular Automata
In contrast to deep reinforcement learning agents, biological neural networks
are grown through a self-organized developmental process. Here we propose a new
hypernetwork approach to grow artificial neural networks based on neural
cellular automata (NCA). Inspired by self-organising systems and
information-theoretic approaches to developmental biology, we show that our
HyperNCA method can grow neural networks capable of solving common
reinforcement learning tasks. Finally, we explore how the same approach can be
used to build developmental metamorphosis networks capable of transforming
their weights to solve variations of the initial RL task.Comment: Paper accepted as a conference paper at ICLR 'From Cells to
Societies' workshop 202
EvoCraft: A New Challenge for Open-Endedness
This paper introduces EvoCraft, a framework for Minecraft designed to study
open-ended algorithms. We introduce an API that provides an open-source Python
interface for communicating with Minecraft to place and track blocks. In
contrast to previous work in Minecraft that focused on learning to play the
game, the grand challenge we pose here is to automatically search for
increasingly complex artifacts in an open-ended fashion. Compared to other
environments used to study open-endedness, Minecraft allows the construction of
almost any kind of structure, including actuated machines with circuits and
mechanical components. We present initial baseline results in evolving simple
Minecraft creations through both interactive and automated evolution. While
evolution succeeds when tasked to grow a structure towards a specific target,
it is unable to find a solution when rewarded for creating a simple machine
that moves. Thus, EvoCraft offers a challenging new environment for automated
search methods (such as evolution) to find complex artifacts that we hope will
spur the development of more open-ended algorithms. A Python implementation of
the EvoCraft framework is available at:
https://github.com/real-itu/Evocraft-py
MarioGPT: Open-Ended Text2Level Generation through Large Language Models
Procedural Content Generation (PCG) algorithms provide a technique to
generate complex and diverse environments in an automated way. However, while
generating content with PCG methods is often straightforward, generating
meaningful content that reflects specific intentions and constraints remains
challenging. Furthermore, many PCG algorithms lack the ability to generate
content in an open-ended manner. Recently, Large Language Models (LLMs) have
shown to be incredibly effective in many diverse domains. These trained LLMs
can be fine-tuned, re-using information and accelerating training for new
tasks. In this work, we introduce MarioGPT, a fine-tuned GPT2 model trained to
generate tile-based game levels, in our case Super Mario Bros levels. We show
that MarioGPT can not only generate diverse levels, but can be text-prompted
for controllable level generation, addressing one of the key challenges of
current PCG techniques. As far as we know, MarioGPT is the first text-to-level
model. We also combine MarioGPT with novelty search, enabling it to generate
diverse levels with varying play-style dynamics (i.e. player paths). This
combination allows for the open-ended generation of an increasingly diverse
range of content
Growing 3D Artefacts and Functional Machines with Neural Cellular Automata
Neural Cellular Automata (NCAs) have been proven effective in simulating
morphogenetic processes, the continuous construction of complex structures from
very few starting cells. Recent developments in NCAs lie in the 2D domain,
namely reconstructing target images from a single pixel or infinitely growing
2D textures. In this work, we propose an extension of NCAs to 3D, utilizing 3D
convolutions in the proposed neural network architecture. Minecraft is selected
as the environment for our automaton since it allows the generation of both
static structures and moving machines. We show that despite their simplicity,
NCAs are capable of growing complex entities such as castles, apartment blocks,
and trees, some of which are composed of over 3,000 blocks. Additionally, when
trained for regeneration, the system is able to regrow parts of simple
functional machines, significantly expanding the capabilities of simulated
morphogenetic systems. The code for the experiment in this paper can be found
at: https://github.com/real-itu/3d-artefacts-nca
The Gaia-ESO Survey::the present-day radial metallicity distribution of the Galactic disc probed by pre-main-sequence clusters
Context. The radial metallicity distribution in the Galactic thin disc represents a crucial constraint for modelling disc formation and evolution. Open star clusters allow us to derive both the radial metallicity distribution and its evolution over time.
Aims. In this paper we perform the first investigation of the present-day radial metallicity distribution based on [Fe/H] determinations in late type members of pre-main-sequence clusters. Because of their youth, these clusters are therefore essential for tracing the current interstellar medium metallicity.
Methods. We used the products of the Gaia-ESO Survey analysis of 12 young regions (age < 100 Myr), covering Galactocentric distances from 6.67 to 8.70 kpc. For the first time, we derived the metal content of star forming regions farther than 500 pc from the Sun. Median metallicities were determined through samples of reliable cluster members. For ten clusters the membership analysis is discussed in the present paper, while for other two clusters (i.e. Chamaeleon I and Gamma Velorum) we adopted the members identified in our previous works.
Results. All the pre-main-sequence clusters considered in this paper have close-to-solar or slightly sub-solar metallicities. The radial metallicity distribution traced by these clusters is almost flat, with the innermost star forming regions having [Fe/H] values that are 0.10−0.15 dex lower than the majority of the older clusters located at similar Galactocentric radii.
Conclusions. This homogeneous study of the present-day radial metallicity distribution in the Galactic thin disc favours models that predict a flattening of the radial gradient over time. On the other hand, the decrease of the average [Fe/H] at young ages is not easily explained by the models. Our results reveal a complex interplay of several processes (e.g. star formation activity, initial mass function, supernova yields, gas flows) that controlled the recent evolution of the Milky Way
Goal-Guided Neural Cellular Automata: Learning to Control Self-Organising Systems
Inspired by cellular growth and self-organization, Neural Cellular Automata
(NCAs) have been capable of "growing" artificial cells into images, 3D
structures, and even functional machines. NCAs are flexible and robust
computational systems but -- similarly to many other self-organizing systems --
inherently uncontrollable during and after their growth process. We present an
approach to control these type of systems called Goal-Guided Neural Cellular
Automata (GoalNCA), which leverages goal encodings to control cell behavior
dynamically at every step of cellular growth. This approach enables the NCA to
continually change behavior, and in some cases, generalize its behavior to
unseen scenarios. We also demonstrate the robustness of the NCA with its
ability to preserve task performance, even when only a portion of cells receive
goal information