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+
+
+
+ 20241017163917-4f4fe0a5a17aadd329d49a1d4b8b2a9d29d99cdc
+ 20241017163917
+
+ JOSS Admin
+ admin@theoj.org
+
+ The Open Journal
+
+
+
+
+ Journal of Open Source Software
+ JOSS
+ 2475-9066
+
+ 10.21105/joss
+ https://joss.theoj.org
+
+
+
+
+ 10
+ 2024
+
+
+ 9
+
+ 102
+
+
+
+ MODULO: A Python toolbox for data-driven modal
+decomposition
+
+
+
+ R.
+ Poletti
+ https://orcid.org/0000-0003-3566-6956
+
+
+ L.
+ Schena
+ https://orcid.org/0000-0002-7183-0242
+
+
+ D.
+ Ninni
+ https://orcid.org/0000-0002-7179-3322
+
+
+ M. A.
+ Mendez
+ https://orcid.org/0000-0002-1115-2187
+
+
+
+ 10
+ 17
+ 2024
+
+
+ 6753
+
+
+ 10.21105/joss.06753
+
+
+ http://creativecommons.org/licenses/by/4.0/
+ http://creativecommons.org/licenses/by/4.0/
+ http://creativecommons.org/licenses/by/4.0/
+
+
+
+ Software archive
+ 10.5281/zenodo.13939520
+
+
+ GitHub review issue
+ https://github.com/openjournals/joss-reviews/issues/6753
+
+
+
+ 10.21105/joss.06753
+ https://joss.theoj.org/papers/10.21105/joss.06753
+
+
+ https://joss.theoj.org/papers/10.21105/joss.06753.pdf
+
+
+
+
+
+ Spectral proper orthogonal
+decomposition
+ Sieber
+ Journal of Fluid Mechanics
+ 792
+ 10.1017/jfm.2016.103
+ 2016
+ Sieber, M., Paschereit, C. O., &
+Oberleithner, K. (2016). Spectral proper orthogonal decomposition.
+Journal of Fluid Mechanics, 792, 798–828.
+https://doi.org/10.1017/jfm.2016.103
+
+
+ POD preprocessing of IR thermal data to
+assess heat source distributions
+ Ranc
+ Experimental Mechanics
+ 55
+ 10.1007/s11340-014-9858-2
+ 2014
+ Ranc, N., Blanche, A., Ryckelynck,
+D., & Chrysochoos, A. (2014). POD preprocessing of IR thermal data
+to assess heat source distributions. Experimental Mechanics, 55,
+725–739.
+https://doi.org/10.1007/s11340-014-9858-2
+
+
+ MODULO: A software for multiscale proper
+orthogonal decomposition of data
+ Ninni
+ SoftwareX
+ 12
+ 10.1016/j.softx.2020.100622
+ 2020
+ Ninni, D., & Mendez, M. A.
+(2020). MODULO: A software for multiscale proper orthogonal
+decomposition of data. SoftwareX, 12, 100622.
+https://doi.org/10.1016/j.softx.2020.100622
+
+
+ Multi-scale proper orthogonal decomposition
+of complex fluid flows
+ Mendez
+ Journal of Fluid Mechanics
+ 870
+ 10.1017/jfm.2019.212
+ 2019
+ Mendez, M. A., Balabane, M., &
+Buchlin, J.-M. (2019). Multi-scale proper orthogonal decomposition of
+complex fluid flows. Journal of Fluid Mechanics, 870, 988–1036.
+https://doi.org/10.1017/jfm.2019.212
+
+
+ Dynamic mode decomposition of numerical and
+experimental data
+ Schmid
+ Journal of Fluid Mechanics
+ 656
+ 10.1017/S0022112010001217
+ 2010
+ Schmid, P. J. (2010). Dynamic mode
+decomposition of numerical and experimental data. Journal of Fluid
+Mechanics, 656, 5–28.
+https://doi.org/10.1017/S0022112010001217
+
+
+ Spectral proper orthogonal decomposition and
+its relationship to dynamic mode decomposition and resolvent
+analysis
+ Towne
+ Journal of Fluid Mechanics
+ 847
+ 10.1017/jfm.2018.283
+ 2018
+ Towne, A., Schmidt, O. T., &
+Colonius, T. (2018). Spectral proper orthogonal decomposition and its
+relationship to dynamic mode decomposition and resolvent analysis.
+Journal of Fluid Mechanics, 847, 821–867.
+https://doi.org/10.1017/jfm.2018.283
+
+
+ Linear and nonlinear dimensionality reduction
+from fluid mechanics to machine learning
+ Mendez
+ Measurement Science and
+Technology
+ 34
+ 10.1088/1361-6501/acaffe
+ 2023
+ Mendez, M. A. (2023). Linear and
+nonlinear dimensionality reduction from fluid mechanics to machine
+learning. Measurement Science and Technology, 34, 042001.
+https://doi.org/10.1088/1361-6501/acaffe
+
+
+ Modal analysis of fluid flows: Applications
+and outlook
+ Taira
+ AIAA Journal
+ 3
+ 58
+ 10.2514/1.J058462
+ 2020
+ Taira, K., Hemati, M. S., Brunton, S.
+L., Sun, Y., Duraisamy, K., Bagheri, S., Dawson, S. T. M., & Yeh,
+C.-A. (2020). Modal analysis of fluid flows: Applications and outlook.
+AIAA Journal, 58(3), 998–1022.
+https://doi.org/10.2514/1.J058462
+
+
+ PyDMD: Python dynamic mode
+decomposition
+ Demo
+ Journal of Open Source
+Software
+ 22
+ 3
+ 10.21105/joss.00530
+ 2018
+ Demo, N., Tezzele, M., & Rozza,
+G. (2018). PyDMD: Python dynamic mode decomposition. Journal of Open
+Source Software, 3(22), 530.
+https://doi.org/10.21105/joss.00530
+
+
+ PySPOD: A Python package for Spectral Proper
+Orthogonal Decomposition (SPOD)
+ Mengaldo
+ Journal of Open Source
+Software
+ 60
+ 6
+ 10.21105/joss.02862
+ 2021
+ Mengaldo, G., & Maulik, R.
+(2021). PySPOD: A Python package for Spectral Proper Orthogonal
+Decomposition (SPOD). Journal of Open Source Software, 6(60), 2862.
+https://doi.org/10.21105/joss.02862
+
+
+ Spectral proper orthogonal
+decomposition
+ Hatzissawidis
+ 2023
+ Hatzissawidis, G., & Sieber, M.
+(2023). Spectral proper orthogonal decomposition.
+https://github.com/grigorishat/SPyOD.
+
+
+ Unlocking massively parallel spectral proper
+orthogonal decompositions in the PySPOD package
+ Rogowski
+ Computer Physics
+Communications
+ 302
+ 10.1016/j.cpc.2024.109246
+ 0010-4655
+ 2024
+ Rogowski, M., Yeung, B. C. Y.,
+Schmidt, O. T., Maulik, R., Dalcin, L., Parsani, M., & Mengaldo, G.
+(2024). Unlocking massively parallel spectral proper orthogonal
+decompositions in the PySPOD package. Computer Physics Communications,
+302, 109246.
+https://doi.org/10.1016/j.cpc.2024.109246
+
+
+
+
+
+
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+
+
+
+
+
+
+
+Journal of Open Source Software
+JOSS
+
+2475-9066
+
+Open Journals
+
+
+
+6753
+10.21105/joss.06753
+
+MODULO: A Python toolbox for data-driven modal
+decomposition
+
+
+
+https://orcid.org/0000-0003-3566-6956
+
+Poletti
+R.
+
+
+
+
+
+https://orcid.org/0000-0002-7183-0242
+
+Schena
+L.
+
+
+
+
+
+https://orcid.org/0000-0002-7179-3322
+
+Ninni
+D.
+
+
+
+
+https://orcid.org/0000-0002-1115-2187
+
+Mendez
+M. A.
+
+
+*
+
+
+
+von Karman Insitute for Fluid Dynamics
+
+
+
+
+University of Ghent, Belgium
+
+
+
+
+Vrije Universiteit Brussel (VUB), Belgium
+
+
+
+
+Politecnico di Bari, Italy
+
+
+
+
+* E-mail:
+
+
+5
+12
+2023
+
+9
+102
+6753
+
+Authors of papers retain copyright and release the
+work under a Creative Commons Attribution 4.0 International License (CC
+BY 4.0)
+2022
+The article authors
+
+Authors of papers retain copyright and release the work under
+a Creative Commons Attribution 4.0 International License (CC BY
+4.0)
+
+
+
+Python
+fluid dynamics
+modal decomposition
+
+
+
+
+
+ Summary
+
Dimensionality reduction is an essential tool in processing large
+ datasets, enabling data compression, pattern recognition, and
+ reduced-order modeling. Many linear tools for dimensionality reduction
+ have been developed in fluid mechanics, where they have been
+ formulated to identify coherent structures and build reduced-order
+ models of turbulent flows
+ (Ranc
+ et al., 2014). This work proposes a major upgrade of the
+ software package MODULO (MODal mULtiscale pOd)
+ (Ninni
+ & Mendez, 2020), which was designed to perform Multiscale
+ Proper Orthogonal Decomposition (mPOD)
+ (Mendez
+ et al., 2019). In addition to implementing the classic Fourier
+ Transform (DFT) and Proper Orthogonal Decomposition (POD), MODULO now
+ also allows for computing Dynamic Mode Decomposition (DMD)
+ (Schmid,
+ 2010) as well as the Spectral POD by Sieber et al.
+ (2016),
+ the Spectral POD by Towne et al.
+ (2018)
+ and a generalized kernel-based decomposition akin to kernel PCA
+ (Mendez,
+ 2023). All algorithms are wrapped in a ‘SciKit’-like Python
+ API, which allows computing all decompositions in one line of code.
+ Documentation, exercises, and video tutorials are also provided to
+ offer a primer on data drive modal analysis.
+
+
+ Statement of Need
+
As extensively illustrated in recent reviews
+ (Mendez,
+ 2023;
+ Taira
+ et al., 2020), all modal decompositions can be considered as
+ special matrix factorizations. The matrix being factorized collects
+ (many) snapshots (samples) of a high-dimensional variable. The
+ factorization provides a basis for the matrix’s column and row spaces
+ to identify the most essential patterns (modes) according to a certain
+ criterion. In what follows, we will refer to common terminologies in
+ fluid dynamics. Nevertheless, it is worth stressing that these tools
+ can be applied to any high-dimensional dataset to identify patterns
+ and build reduced-order models
+ (Mendez
+ et al., 2019). In the common arrangement encountered in fluid
+ dynamics, the basis for the column space is a set of ‘spatial
+ structures’ while the basis for the row space is a set of `temporal
+ structures’. These are paired by a scalar, which defines their
+ relative importance. The POD, closely related to Principal Component
+ Analysis, yields modes with the highest energy (variance) content and,
+ in addition, guarantees their orthonormality by construction. In the
+ DFT, as implemented in MODULO, modes are defined to evolve as
+ orthonormal complex exponential in time. This implies that the
+ associated frequencies are integer multiples of a fundamental tone.
+ The DMD generalizes the DFT by releasing the orthogonality constraint
+ and considering complex frequencies, i.e., modes that can vanish or
+ explode. Both the constraint of energy optimality and harmonic modes
+ can lead to poor convergence and feature detection performances. This
+ motivated the development of hybrid methods such as the Spectral POD
+ by Towne et al.
+ (2018),
+ Spectral POD by Sieber et al.
+ (2016),
+ and Multiscale Proper Orthogonal Decomposition (mPOD)
+ (Mendez
+ et al., 2019). The first can be seen as an optimally averaged
+ DMD, while the second combines POD and DFT with a filtering operation.
+ Both SPODs assume statistically stationary data and are designed to
+ identify harmonic (or quasi-harmonic) modes. The mPOD combines POD
+ with Multi-resolution Analysis (MRA) to provide optimal modes within a
+ prescribed frequency band. The mPOD modes are thus spectrally less
+ narrow than those obtained by the SPODs, but this allows for
+ localizing them in time (i.e., potentially having compact support in
+ time). Finally, recent developments in nonlinear methods such as
+ kernel PCA and their applications to fluid dynamics (see Mendez
+ (2023))
+ have motivated the interest in the connection between nonlinear
+ methods and the most general Karhunen-Loeve expansion (KL). This
+ generalizes the POD as the decomposition of data onto the
+ eigenfunction of a kernel function (the POD being a KL for the case of
+ linear kernel).
+
MODULO provides a unified tool to carry out different
+ decompositions with a shared API. This simplifies comparing different
+ techniques and streamlines their application to a given dataset
+ (problem). In addition, it is the only package that includes the mPOD
+ and the generalized KL with kernel functions interfacing with
+ SciKit-learn. For decomposition-specific packages, we refer the reader
+ to many excellent Python APIs that are available to compute the POD,
+ DMD, and both SPODs, for example
+ (Demo
+ et al., 2018;
+ Hatzissawidis
+ & Sieber, 2023;
+ Mengaldo
+ & Maulik, 2021;
+ Rogowski
+ et al., 2024).
+
+
+ New Features
+
This manuscript accompanies MODULO version 2.0. This version
+ features four new decompositions: the two SPODs, the DMD, and the
+ general KL. It also allows for different approaches to computing the
+ POD (interfacing with various SVD/EIG solvers from Scipy and
+ SciKit-learn) and a first implementation for nonuniform grids. The
+ memory-saving feature has been improved, and the software can now
+ handle 3D decompositions.
+
+
+ Conclusions
+
MODULO is a versatile and user-friendly toolbox for data-driven
+ modal decomposition. It provides a unified interface to various
+ decomposition methods, allowing for a straightforward comparison and
+ benchmarking. The package allows for modal decompositions in one line
+ of code. It is also designed to handle large datasets via the
+ so-called “memory saving” option and can handle nonuniformly sampled
+ data.
+
+
+ Acknowledgements
+
R. Poletti and L. Schena are supported by Fonds Wetenschappelijk
+ Onderzoek (FWO), grant numbers 1SD7823N and 1S75825N,
+ respectively.
+
+
+
+
+
+
+
+
+ SieberMoritz
+ PaschereitC. Oliver
+ OberleithnerKilian
+
+ Spectral proper orthogonal decomposition
+
+ Cambridge University Press
+ 2016
+ 792
+ 10.1017/jfm.2016.103
+ 798
+ 828
+
+
+
+
+
+ RancNicolas
+ BlancheAntoione
+ RyckelynckD.
+ ChrysochoosAndre
+
+ POD preprocessing of IR thermal data to assess heat source distributions
+
+ 201404
+ 55
+ 10.1007/s11340-014-9858-2
+ 725
+ 739
+
+
+
+
+
+ NinniDavide
+ MendezMiguel A.
+
+ MODULO: A software for multiscale proper orthogonal decomposition of data
+
+ 202012
+ 12
+ 10.1016/j.softx.2020.100622
+ 100622
+
+
+
+
+
+
+ MendezMiguel A.
+ BalabaneM.
+ BuchlinJ.-M.
+
+ Multi-scale proper orthogonal decomposition of complex fluid flows
+
+ Cambridge University Press
+ 2019
+ 870
+ 10.1017/jfm.2019.212
+ 988
+ 1036
+
+
+
+
+
+ SchmidPeter J.
+
+ Dynamic mode decomposition of numerical and experimental data
+
+ Cambridge University Press
+ 2010
+ 656
+ 10.1017/S0022112010001217
+ 5
+ 28
+
+
+
+
+
+ TowneAaron
+ SchmidtOliver T.
+ ColoniusTim
+
+ Spectral proper orthogonal decomposition and its relationship to dynamic mode decomposition and resolvent analysis
+
+ Cambridge University Press
+ 2018
+ 847
+ 10.1017/jfm.2018.283
+ 821
+ 867
+
+
+
+
+
+ MendezMiguel A.
+
+ Linear and nonlinear dimensionality reduction from fluid mechanics to machine learning
+
+ 202301
+ 34
+ 10.1088/1361-6501/acaffe
+ 042001
+
+
+
+
+
+
+ TairaKunihiko
+ HematiMaziar S.
+ BruntonSteven L.
+ SunYiyang
+ DuraisamyKarthik
+ BagheriShervin
+ DawsonScott T. M.
+ YehChi-An
+
+ Modal analysis of fluid flows: Applications and outlook
+
+ 2020
+ 58
+ 3
+ https://doi.org/10.2514/1.J058462
+ 10.2514/1.J058462
+ 998
+ 1022
+
+
+
+
+
+ DemoNicola
+ TezzeleMarco
+ RozzaGianluigi
+
+ PyDMD: Python dynamic mode decomposition
+
+ 2018
+ 3
+ 22
+ 10.21105/joss.00530
+ 530
+
+
+
+
+
+
+ MengaldoGianmarco
+ MaulikRomit
+
+ PySPOD: A Python package for Spectral Proper Orthogonal Decomposition (SPOD)
+
+ The Open Journal
+ 2021
+ 6
+ 60
+ https://doi.org/10.21105/joss.02862
+ 10.21105/joss.02862
+ 2862
+
+
+
+
+
+
+ HatzissawidisGrigorios
+ SieberMoritz
+
+ Spectral proper orthogonal decomposition
+ https://github.com/grigorishat/SPyOD
+ 2023
+
+
+
+
+
+ RogowskiMarcin
+ YeungBrandon C. Y.
+ SchmidtOliver T.
+ MaulikRomit
+ DalcinLisandro
+ ParsaniMatteo
+ MengaldoGianmarco
+
+ Unlocking massively parallel spectral proper orthogonal decompositions in the PySPOD package
+
+ 2024
+ 302
+ 0010-4655
+ https://www.sciencedirect.com/science/article/pii/S0010465524001693
+ 10.1016/j.cpc.2024.109246
+ 109246
+
+
+
+
+
+