César Piñeiro

dblp:217/8656 · DBLP profile ↗
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10ranked-venue papers
5as first author
7since 2021 · last 2026
0000-0001-6490-7128ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Systems, architecture and hardware · 8 · 4 first-author · 7 since 2021Software engineering, systems software and programming languages · 1 · 1 first-author · 1 since 2021Databases, data management, data science and information retrieval · 1Applied, interdisciplinary, general and emerging computing · 1 · 1 first-author
YearPublicationVenuePosition
2026 Unlocking Python Multithreading Capabilities using OpenMP-Based Programming with OMP4Py
abstract
Python exhibits inferior performance relative to traditional high performance computing (HPC) languages such as C, C++, and Fortran. This performance gap is largely due to Python’s interpreted nature and the Global Interpreter Lock (GIL), which restricts multithreading efficiency. However, the introduction of a GIL-free variant in the Python interpreter opens the door to more effective exploitation of multithreading parallelism in Python. Based on this important new feature, we introduce OMP4Py with the aim of bringing OpenMP’s familiar directive-based parallelization paradigm to Python. Its dual-runtime architecture design combines the benefits of a pure Python implementation with the performance and low-level capabilities required to maximize efficiency in compute-intensive tasks. In this way, OMP4Py offers both full Python support and the high performance required by HPC workloads.
César Piñeiro, Juan Carlos Pichel
CGO1
2026 NetQIR: An extension of QIR for distributed quantum computing
abstract
The rapid advancement of quantum computing has highlighted the need for scalable and efficient software infrastructures to fully exploit its potential. Current quantum processors face significant scalability constraints due to the limited number of qubits per chip. In response, distributed quantum computing (DQC) —achieved by networking multiple quantum processor units (QPUs)— is emerging as a promising solution. To support this paradigm, robust intermediate representations (IRs) are needed to translate high-level quantum algorithms into executable instructions suitable for distributed systems. This paper presents NetQIR, an extension of Microsoft’s Quantum Intermediate Representation (QIR), specifically designed to facilitate DQC by incorporating new instruction specifications. NetQIR was developed in response to the lack of abstraction at the network and hardware layers identified in the existing literature as a significant obstacle to effectively implementing distributed quantum algorithms. Based on this analysis, NetQIR introduces new essential abstraction features to support compilers in DQC contexts. It defines network communication instructions independent of specific hardware, abstracting the complexities of inter-QPU communication. Although the proposed work allows abstraction of the underlying network, it is important to note that it is intended for the development of high-performance code on future modular quantum architectures. Leveraging the QIR framework, NetQIR aims to bridge the gap between high-level quantum algorithm design and low-level hardware execution, thus promoting modular and scalable approaches to quantum software infrastructures for distributed applications. Furthermore, its design may serve as a foundational component for future implementations of distributed quantum standards such as the Quantum Message Passing Interface (QMPI).
Francisco Javier Cardama, Jorge Vázquez-Pérez, César Piñeiro, Tomás F. Pena, Juan Carlos Pichel, Andrés Gómez 0002
Future Gener. Comput. Syst.3
2026 OMP4Py: A pure Python implementation of openMP
abstract
Python demonstrates lower performance in comparison to traditional high performance computing (HPC) languages such as C, C++, and Fortran. This performance gap is largely due to Python’s interpreted nature and the Global Interpreter Lock (GIL), which hampers multithreading efficiency. However, the latest version of Python includes the necessary changes to make the interpreter thread-safe, allowing Python code to run without the GIL. This important update will enable users to fully exploit multithreading parallelism in Python. In order to facilitate that task, this paper introduces OMP4Py, the first pure Python implementation of OpenMP. We demonstrate that it is possible to bring OpenMP’s familiar directive-based parallelization paradigm to Python, allowing developers to write parallel code with the same level of control and flexibility as in C, C++, or Fortran. The experimental evaluation shows that OMP4Py significantly impacts the performance of various types of applications, although the current threading limitations of Python’s interpreter (v3.13) reduce its effectiveness for numerical applications. • OMP4Py: First pure Python implementation of OpenMP for parallel programming. • Brings OpenMP’s directive-based parallelism to Python. • Combines with mpi4py for hybrid parallelism on clusters. • Supports broader applications than PyOMP, which is limited to numerical tasks.
César Piñeiro, Juan Carlos Pichel
Future Gener. Comput. Syst.1
2025 Review of intermediate representations for quantum computing
abstract
Abstract Intermediate representations (IRs) are fundamental to classical and quantum computing, bridging high-level quantum programming languages and the hardware-specific instructions required for execution. This paper reviews the development of quantum IRs, focusing on their evolution and the need for abstraction layers that facilitate portability and optimization. Monolithic quantum IRs, such as QIR (Lubinski et al. in Front Phys 10:940293, 2022. https://doi.org/10.3389/fphy.2022.940293), QSSA (Peduri et al. in Proceedings of the 31st ACM SIGPLAN international conference on compiler construction. CC 2022. Association for Computing Machinery, New York, 2022), or Q-MLIR (McCaskey and Nguyen in Proceedings-2021 IEEE International Conference on Quantum Computing and Engineering, QCE, 2021), their effectiveness in handling abstractions, and their hybrid support between quantum-classical operations are evaluated. However, a key limitation is their inability to address qubit locality, an essential feature for distributed quantum computing (DQC). To overcome this, InQuIR (Nishio and Wakizaka in InQuIR: Intermediate Representation for Interconnected Quantum Computers, 2023. https://arxiv.org/abs/2302.00267) was introduced as an IR specifically designed for distributed systems, providing explicit control over qubit locality and inter-node communication. While effective in managing qubit distribution, InQuIR’s dependence on manual manipulation of communication protocols increases complexity for developers. NetQIR (Vázquez-Pérez et al. in NetQIR: An Extension of QIR for Distributed Quantum Computing, 2024. https://arxiv.org/abs/2408.03712), an extension of QIR for DQC, emerges as a solution to achieve the abstraction of quantum communications protocols. This review emphasizes the need for further advancements in IRs for distributed quantum systems, which will play a crucial role in the scalability and usability of future quantum networks.
Francisco Javier Cardama, Jorge Vázquez-Pérez, César Piñeiro, Juan Carlos Pichel, Tomás F. Pena, Andrés Gómez 0002
J. Supercomput.3
2025 Inqasm: InQuIR compiler to NetQASM
abstract
Abstract Quantum computing is a rapidly evolving field, with almost every aspect open to change or improvement. This includes moving from using a single quantum processing unit to interconnecting multiple quantum processing units (or several of them), establishing a new paradigm called distributed quantum computing and increasing the overall computing capability. Some research is already underway in this area to prepare the ground for an eventual architecture with these characteristics. This is the case of InQuIR (Nishio and Wakizaka in arXiv:2302.00267 2023) and NetQASM (Dahlberg et al in QST 7:035023 2022), two languages developed for distributed quantum computing. This paper presents the development of the InQASM compiler with the aim of translating code from the InQuIR language to NetQASM, establishing a compilation stack for the new distributed paradigm. An example of this compilation and a simulation of the compiled code are shown to showcase it.
Jorge Vázquez-Pérez, Francisco Javier Cardama, César Piñeiro, Juan Carlos Pichel, Tomás F. Pena, Andrés Gómez 0002
J. Supercomput.3
2024 QPU integration in OpenCL for heterogeneous programming
abstract
Abstract The integration of quantum processing units (QPUs) in a heterogeneous high-performance computing environment requires solutions that facilitate hybrid classical–quantum programming. Standards such as OpenCL facilitate the programming of heterogeneous environments, consisting of CPUs and hardware accelerators. This study presents an innovative method that incorporates QPU functionality into OpenCL, standardizing quantum processes within classical environments. By leveraging QPUs within OpenCL, hybrid quantum–classical computations can be sped up, impacting domains like cryptography, optimization problems, and quantum chemistry simulations. Using Portable Computing Language (Jääskeläinen et al. in Int J Parallel Program 43(5):752–785, 2014. https://doi.org/10.1007/s10766-014-0320-y ) and the Qulacs library (Suzuki et al. in Quantum 5:559, 2021. https://doi.org/10.22331/q-2021-10-06-559 ), results demonstrate, for instance, the successful execution of Shor’s algorithm (Nielsen and Chuang in Quantum computation and quantum information, 10th anniversary edn. Cambridge University Press, Cambridge, 2010), serving as a proof of concept for extending the approach to larger qubit systems and other hybrid quantum–classical algorithms. This integration approach bridges the gap between quantum and classical computing paradigms, paving the way for further optimization and application to a wide range of computational problems.
Jorge Vázquez-Pérez, César Piñeiro, Juan Carlos Pichel, Tomás F. Pena, Andrés Gómez 0002
J. Supercomput.2
2022 A unified framework to improve the interoperability between HPC and Big Data languages and programming models
abstract
One of the most important issues in the path to the convergence of HPC and Big Data is caused by the differences in their software stacks. Despite some research efforts, the interoperability between their programming models and languages is still limited. To deal with this problem we introduce a new computing framework called IgnisHPC, whose main objective is to unify the execution of Big Data and HPC workloads in the same framework. IgnisHPC has native support for multi-language applications using JVM and non-JVM-based languages. Since MPI was used as its backbone technology, IgnisHPC takes advantage of many communication models and network architectures. Moreover, MPI applications can be directly executed in an efficient way in the framework. The main consequence is that users could combine in the same multi-language code HPC tasks (using MPI) with Big Data tasks (using MapReduce operations). The experimental evaluation demonstrates the benefits of our proposal in terms of performance and productivity with respect to other frameworks. IgnisHPC is publicly available for the Big Data and HPC research community.
César Piñeiro, Juan Carlos Pichel
Future Gener. Comput. Syst.1
2020 Very Fast Tree: speeding up the estimation of phylogenies for large alignments through parallelization and vectorization strategies
abstract
MOTIVATION: FastTree-2 is one of the most successful tools for inferring large phylogenies. With speed at the core of its design, there are still important issues in the FastTree-2 implementation that harm its performance and scalability. To deal with these limitations, we introduce VeryFastTree, a highly tuned implementation of the FastTree-2 tool that takes advantage of parallelization and vectorization strategies to boost performance. RESULTS: VeryFastTree is able to construct a tree on a standard server using double-precision arithmetic from an ultra-large 330k alignment in only 4.5 h, which is 7.8× and 3.5× faster than the sequential and best parallel FastTree-2 times, respectively. AVAILABILITY AND IMPLEMENTATION: VeryFastTree is available at the GitHub repository: https://github.com/citiususc/veryfasttree. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
César Piñeiro, José Manuel Abuín, Juan Carlos Pichel
Bioinform.1
2020 Ignis: An efficient and scalable multi-language Big Data framework
César Piñeiro, Rodrigo Martínez-Castaño, Juan Carlos Pichel
Future Gener. Comput. Syst.1
2020 Fast Distributed kNN Graph Construction Using Auto-tuned Locality-sensitive Hashing
abstract
The k -nearest-neighbors ( k NN) graph is a popular and powerful data structure that is used in various areas of Data Science, but the high computational cost of obtaining it hinders its use on large datasets. Approximate solutions have been described in the literature using diverse techniques, among which Locality-sensitive Hashing (LSH) is a promising alternative that still has unsolved problems. We present Variable Resolution Locality-sensitive Hashing, an algorithm that addresses these problems to obtain an approximate k NN graph at a significantly reduced computational cost. Its usability is greatly enhanced by its capacity to automatically find adequate hyperparameter values, a common hindrance to LSH-based methods. Moreover, we provide an implementation in the distributed computing framework Apache Spark that takes advantage of the structure of the algorithm to efficiently distribute the computational load across multiple machines, enabling practitioners to apply this solution to very large datasets. Experimental results show that our method offers significant improvements over the state-of-the-art in the field and shows very good scalability as more machines are added to the computation.
Carlos Eiras-Franco, David Martínez-Rego, Leslie Kanthan, César Piñeiro, Antonio Bahamonde, Bertha Guijarro-Berdiñas, Amparo Alonso-Betanzos
ACM Trans. Intell. Syst. Technol.4