NumPI July 2024

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4 participants
6 discussions

Seminario a Settembre
by Luca SALUZZI 03 Aug '24

03 Aug '24

Cari tutti, vi mando questa email perche' a Settembre, la settimana del 9-13, verra' in visita Maria Strazzullo dal Politecnico di Torino e vorrei organizzare un suo seminario. Si pensava di farlo o Lunedì 9 o Martedi' 10. Voi avete preferenze su data e orario? Così da permettere di massimizzare il numero di partecipanti. Intanto buone vacanze e ci si vede a Settembre!! Ciao, Luca

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23/07/2024 — R. Van Beeumen — Seminari CN1-SPOKE 10 (Quantum Computing)
by Gianna M. Del Corso 23 Jul '24

23 Jul '24

Dear all, This is a reminder for today’s seminar on quantum computing. Title: Hybrid Quantum-Classical Krylov Methods for Eigenvalue Computation Speaker: Roel Van Beeumen (Lawrence Berkeley National Laboratory) Venue: Sala Gerace, Dipartimento di Informatica Time: Tuesday, 23/07/2024, 14:30 Below the link for the online attendance. https://teams.microsoft.com/l/meetup-join/19%3ameeting_MjliOWRmMDAtMjA4ZC00… Everyone is welcome to attend! Gianna @@@@@@@@@@@@@@@@@ Gianna M. Del Corso, PhD Dipartimento di Informatica, Università di Pisa Largo Pontecorvo, 3 56127 Pisa, Italy ph. +39-050-2213118 @@@@@@@@@@@@@@@@@

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Seminar on Quantum Computing: Roel Van Beeumen Tuesday 23/7, 14:30
by Gianna M. Del Corso 16 Jul '24

16 Jul '24

Dear All, As part of the CN1-SPOKE 10 on Quantum Computing, we are pleased to announce the last seminar before the summer break. Title: Hybrid Quantum-Classical Krylov Methods for Eigenvalue Computation Speaker: Roel Van Beeumen (Lawrence Berkeley National Laboratory) Venue: Sala Gerace, Dipartimento di Informatica Time: Tuesday, 23/07/2024, 14:30 Abstract: Classical algorithms based on Krylov subspaces are among the most successful tools in the field of numerical linear algebra. More recently, the emergence of quantum subspace methods has resulted in a promising class of hybrid quantum-classical algorithms for eigenvalue approximation, e.g., in the fields of condensed matter physics and electronic structure theory. These quantum Krylov methods harness quantum computers to generate the subspace basis states and retrieve the projected problem through quantum measurement. However, the classical computation of the Ritz values often poses challenges due to the ill-conditioning of the associated generalized eigenvalue problem. In this talk, we present an overview of quantum subspace algorithms from a numerical linear algebra perspective. We discuss strategies to avoid solving an ill-conditioned eigenvalue problem, explain their implementation on quantum computers, and provide numerical and theoretical evidence of their convergence. Furthermore, we present strategies to improve the robustness, especially in the presence of noise. Everyone is welcome to attend! Gianna @@@@@@@@@@@@@@@@@ Gianna M. Del Corso, PhD Dipartimento di Informatica, Università di Pisa Largo Pontecorvo, 3 56127 Pisa, Italy ph. +39-050-2213118 @@@@@@@@@@@@@@@@@

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[Indico] Dr Jie Meng, Theoretical and computational properties of quasi-Toeplitz M-matrices, 15/07/2024, 15:00 Europe/Rome
by fabio.durastante＠unipi.it 14 Jul '24

14 Jul '24

Title: Theoretical and computational properties of quasi-Toeplitz M-matrices, Speaker(s): Dr Jie Meng, Ocean University of China, Date and time: 15 Jul 2024, 15:00 (Europe/Rome), Lecture series: Seminar on Numerical Analysis, Venue: Dipartimento di Matematica (Sala Riunioni). You can access the full event here: https://events.dm.unipi.it/e/287 Abstract -------- A quasi-Toeplitz matrix is a semi-infinite matrix of the form $A=T(a)+E$, where $T(a)$ is a Toeplitz matrix with entries $(T(a))_{i,j}=a_{j-i}$, for $a_{j-i}\in\mathbb C$, $i,j\ge 1$ and $E$ is a compact correction. Quasi-Toeplitz $M$-matrices are encountered in the study of quadratic matrix equations arising in the analysis of a 2-dimensional Quasi-Birth-Death (QBD) stochastic process. We investigate the properties of such matrices and provide conditions under which a quasi-Toeplitz matrix is an $M$-matrix. We show that under a mild and easy-to-check condition, an invertible quasi-Toeplitz $M$-matrix has a unique square root that is an $M$-matrix possessing quasi-Toeplitz structure. Some issues concerning the computation of the square root of quasi-Toeplitz $M$-matrices are discussed and numerical experiments are performed -- Indico :: Email Notifier https://events.dm.unipi.it/e/287

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Difesa dottorato
by Angelo Alberto CASULLI 12 Jul '24

12 Jul '24

Cari tutti, Lunedì 22 luglio alle 14.30 discuterò la mia tesi di dottorato dal titolo "Block rational Krylov methods for matrix equations and matrix functions" presso la Scuola Normale. Chiunque abbia piacere di partecipare è il benvenuto! Seguirà un piccolo rinfresco nel chiostro della Scuola. A presto, Angelo Casulli

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[Indico] Dr Jie Meng, Theoretical and computational properties of quasi-Toeplitz M-matrices, 7/15/24, 3:00 PM Europe/Rome
by fabio.durastante＠unipi.it 04 Jul '24

04 Jul '24

Title: Theoretical and computational properties of quasi-Toeplitz M-matrices, Speaker(s): Dr Jie Meng, Ocean University of China, Date and time: Jul 15, 2024, 3:00 PM (Europe/Rome), Lecture series: Seminar on Numerical Analysis, Venue: Dipartimento di Matematica (Sala Riunioni). You can access the full event here: https://events.dm.unipi.it/e/287 Abstract -------- A quasi-Toeplitz matrix is a semi-infinite matrix of the form $A=T(a)+E$, where $T(a)$ is a Toeplitz matrix with entries $(T(a))_{i,j}=a_{j-i}$, for $a_{j-i}\in\mathbb C$, $i,j\ge 1$ and $E$ is a compact correction. Quasi-Toeplitz $M$-matrices are encountered in the study of quadratic matrix equations arising in the analysis of a 2-dimensional Quasi-Birth-Death (QBD) stochastic process. We investigate the properties of such matrices and provide conditions under which a quasi-Toeplitz matrix is an $M$-matrix. We show that under a mild and easy-to-check condition, an invertible quasi-Toeplitz $M$-matrix has a unique square root that is an $M$-matrix possessing quasi-Toeplitz structure. Some issues concerning the computation of the square root of quasi-Toeplitz $M$-matrices are discussed and numerical experiments are performed -- Indico :: Email Notifier https://events.dm.unipi.it/e/287

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