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Preprints
[2] | Asymptotic log-det sum-of-ranks minimization via tensor (alternating) iteratively reweighted least squares. S. Krämer, arXiv:2106.15201 (2021) [arXiv] |
[1] | Asymptotic log-det rank minimization via (alternating) iteratively reweighted least squares. S. Krämer, arXiv:2106.14644 (2021) [arXiv] |
Publications
[3] | A geometric description of feasible singular values in the tensor train format. S. Krämer, SIAM Journal on Matrix Analysis and Applications, 40, pp. 1153-1178 (2019) [epubs.siam] |
[2] | Stable ALS approximation in the TT-format for rank-adaptive tensor completion. L. Grasedyck and S. Krämer, Numer. Math. 143, 855–904 (2019) [springer link] |
[1] | Variants of alternating least squares tensor completion in the tensor train format. L. Grasedyck, M. Kluge, and S. Krämer, SIAM Journal on Scientific Computing 37, pp. A2424-A2450 (2015) [epubs.siam] |
PhD Thesis
Tree tensor networks, associated singular values and high-dimensional approximation. S. Krämer, RWTH Aachen University (2020) [publications.rwth-aachen] |
Talks (little excerpt)
[i_4] | Guaranteed and fast construction of tensors with prescribed largest multilinear singular values. Online Minisymposium on Low-rank Geometry and Computation, organized by MPI, Leipzig, Germany (2020) [online] |
[i_3] | Approximate interpolation of high dimensional, scattered data in tree tensor formats. Algorithms and Applications of High Dimensional Approximation, Bath, England (2019) [Bath] |
[i_2] | Feasible singular values for hierarchical tensors. Algebraic Geometry, Approximation, and Optimisation, Creswick, Australia (2018) [Crezwick] |
[i_1] | Stable ALS Approximation for Rank-Adaptive Tensor Completion. GAMM Jahrestagung, Munich, Germany (2018) [Munich] |
Repositories
![]() | (A)IRLS Library Matlab implementations of (alternating) IRLS algorithms for affine vector cardinality, matrix rank and tensor sum-of-rank minimization. [Git Repository] |
![]() | Button Plot Custom plot function that iteratively combines clusters of visually intersecting disks in a scatter plot avoiding quadratic complexity. [Mathworks File Exchange] |
![]() | Tensor Node Toolbox (beta version) Toolbox for labeled, automatized tensor network arithmetic. [Git Repository] [Live Script Walkthrough] |
![]() | TT Feasibility Mini-Toolbox Mini-toolbox for "A Geometrical Description of Feasible Singular Values in the Tensor Train Format" [Git Repository] [Live Script Walkthrough] |
![]() | G2S3 (2017) Updated Course Material: Low Rank Tensor Formats Updated exercises for the 2017 Gen Golub Summer School on Data Sparse Approximations and Algorithms for the course Low Rank Tensor Formats. [Git Repository] |
![]() | SALSA Implementation Implementation of SALSA for "Stable ALS Approximation in the TT-Format for Rank-Adaptive Tensor Completion" [Git Repository] [Singular Value Plot] |
Code Golf Art: Savanna Runs in Matlab command window (modified submission to the Matlab Central 20th Anniversary Minihack Contest)
figure;X=-10:.02:10;colormap([pink.*autumn;1,1,.9]);image(782./abs(X+1i*X'-3i)); |
Teaching Activities
[SS21] | Numerische Mathematik II (for mathematicians), two times substitutional lecturer, assistant |
[WS1920 / WS2021] | Numerische Mathematik I (for mathematicians), assistant |
[WS1819 / SS19 / SS20 / WS2122] | Mathematik I/II (for civil engineers), assistant |
[SS18] | Begleitpraktikum II (for mathematicians), assistant |
[2017] | Gene Golub Summer School on Data Sparse Approximations and Algorithms (SIAM), assistant and creator of course material |
[WS1617 / WS1718] | Numerische Mathematik IV (for mathematicians), assistant |
[SS17] | Numerische Mathematik (for electrical engineers), assistant |
[SS16 / WS2122] | Seminar "Aktuelle Themen der Numerik" (for mathematicians) / Numerische Multilineare Algebra (for mathematicians), assistant |
[WS1415 / SS15 / WS1516] | Numerische Mathematik I-III (for mathematicians), assistant |
[Several years during studies] | Begleitpraktikum I / II (for mathematicians), student assistant / examiner |
Other
[since 2017] | GAMM membership and regular participation in yearly conference |
[since 2015] | Review activity for SIAM |