Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
143 tokens/sec
GPT-4o
7 tokens/sec
Gemini 2.5 Pro Pro
46 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

Fast Computation of Moore-Penrose Inverse Matrices (0804.4809v1)

Published 30 Apr 2008 in cs.NE

Abstract: Many neural learning algorithms require to solve large least square systems in order to obtain synaptic weights. Moore-Penrose inverse matrices allow for solving such systems, even with rank deficiency, and they provide minimum-norm vectors of synaptic weights, which contribute to the regularization of the input-output mapping. It is thus of interest to develop fast and accurate algorithms for computing Moore-Penrose inverse matrices. In this paper, an algorithm based on a full rank Cholesky factorization is proposed. The resulting pseudoinverse matrices are similar to those provided by other algorithms. However the computation time is substantially shorter, particularly for large systems.

Citations (235)

Summary

  • The paper introduces a new algorithm for faster computation of Moore-Penrose inverse matrices using a full rank Cholesky factorization method.
  • The algorithm demonstrates significant computational efficiency gains over traditional SVD and Gram-Schmidt methods, especially for large matrices.
  • Practical implications include improved efficiency for large least square systems in neural network learning and other real-time or incremental applications.

Fast Computation of Moore-Penrose Inverse Matrices

In the context of neural network learning algorithms, the computation of synaptic weights often necessitates the resolution of large least square systems. The Moore-Penrose inverse matrices, known for providing solutions with minimum-norm vectors, serve as a critical tool in addressing rank-deficient systems. Pierre Courrieu's paper introduces an algorithm that significantly expedites the computation of these pseudoinverse matrices using a full rank Cholesky factorization technique. This method presents a computational efficiency advantage, particularly for large matrices, over traditional approaches such as Singular Value Decomposition (SVD) and Gram-Schmidt orthonormalization (GSO).

The essence of Courrieu's approach is rooted in its ability to maintain the properties of the Moore-Penrose inverse while reducing computational time. The proposed algorithm leverages the full rank Cholesky factorization of potentially singular symmetric positive matrices. By focusing on the unique upper triangular matrix derived during the factorization process, the algorithm ensures that each column of the pseudoinverse matrix achieves the minimum-norm condition crucial for regularizing neural network mappings.

Courrieu's paper details a comparative computational analysis that highlights the algorithm's performance against established methods such as the SVD and Greville's algorithms. Tests were conducted on matrices of increasing sizes, revealing the algorithm's substantial speed advantage in larger matrices, although slight performance trade-offs were observed in smaller matrices due to inherent mathematical operations such as square root calculations.

Theoretical and practical implications of this research extend to various fields that rely on rapid computations of least square systems, including neurocomputational learning procedures. The capability to handle rank-deficient matrices efficiently allows for greater flexibility in modeling choices, reducing the risks associated with ill-conditioned systems and providing reliability in numerical results. Additionally, the ability to perform these computations rapidly is particularly beneficial for on-line and incremental learning scenarios where real-time or iterative updates are crucial.

Moving forward, this work opens avenues for enhancing performance in parallel computing environments, as the underlying operations can scale effectively with processor availability. The integration of this algorithm into learning architectures not only enhances computational efficiency but also supports dynamic architectural adjustments, such as rescaling basis functions as network demands evolve.

In conclusion, Courrieu's contribution provides a meaningful advancement in the efficient computation of Moore-Penrose inverse matrices. It suggests potential for future developments in AI applications where large-scale, real-time data processing necessitates robust and rapid computational methodologies.