Efficient Tensor Operations Via Compression and Parallel Computation
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Short and Deep: Sketching and Neural Networks
SHORT AND DEEP: SKETCHING AND NEURAL NETWORKS Amit Daniely, Nevena Lazic, Yoram Singer, Kunal Talwar∗ Google Brain ABSTRACT Data-independent methods for dimensionality reduction such as random projec- tions, sketches, and feature hashing have become increasingly popular in recent years. These methods often seek to reduce dimensionality while preserving the hypothesis class, resulting in inherent lower bounds on the size of projected data. For example, preserving linear separability requires Ω(1/γ2) dimensions, where γ is the margin, and in the case of polynomial functions, the number of required di- mensions has an exponential dependence on the polynomial degree. Despite these limitations, we show that the dimensionality can be reduced further while main- taining performance guarantees, using improper learning with a slightly larger hypothesis class. In particular, we show that any sparse polynomial function of a sparse binary vector can be computed from a compact sketch by a single-layer neu- ral network, where the sketch size has a logarithmic dependence on the polyno- mial degree. A practical consequence is that networks trained on sketched data are compact, and therefore suitable for settings with memory and power constraints. We empirically show that our approach leads to networks with fewer parameters than related methods such as feature hashing, at equal or better performance. 1 INTRODUCTION In many supervised learning problems, input data are high-dimensional and sparse. The high di- mensionality may be inherent in the domain, such as a large vocabulary in a language model, or the result of creating hybrid conjunction features. This setting poses known statistical and compu- tational challenges for standard supervised learning techniques, as high-dimensional inputs lead to models with a very large number of parameters. -
Low-Rank Tucker Approximation of a Tensor from Streaming Data : ; \ \ } Yiming Sun , Yang Guo , Charlene Luo , Joel Tropp , and Madeleine Udell
SIAM J. MATH.DATA SCI. © 2020 Society for Industrial and Applied Mathematics Vol. 2, No. 4, pp. 1123{1150 Low-Rank Tucker Approximation of a Tensor from Streaming Data˚ : ; x { } Yiming Sun , Yang Guo , Charlene Luo , Joel Tropp , and Madeleine Udell Abstract. This paper describes a new algorithm for computing a low-Tucker-rank approximation of a tensor. The method applies a randomized linear map to the tensor to obtain a sketch that captures the important directions within each mode, as well as the interactions among the modes. The sketch can be extracted from streaming or distributed data or with a single pass over the tensor, and it uses storage proportional to the degrees of freedom in the output Tucker approximation. The algorithm does not require a second pass over the tensor, although it can exploit another view to compute a superior approximation. The paper provides a rigorous theoretical guarantee on the approximation error. Extensive numerical experiments show that the algorithm produces useful results that improve on the state-of-the-art for streaming Tucker decomposition. Key words. Tucker decomposition, tensor compression, dimension reduction, sketching method, randomized algorithm, streaming algorithm AMS subject classifcations. 68Q25, 68R10, 68U05 DOI. 10.1137/19M1257718 1. Introduction. Large-scale datasets with natural tensor (multidimensional array) struc- ture arise in a wide variety of applications, including computer vision [39], neuroscience [9], scientifc simulation [3], sensor networks [31], and data mining [21]. In many cases, these tensors are too large to manipulate, to transmit, or even to store in a single machine. Luckily, tensors often exhibit a low-rank structure and can be approximated by a low-rank tensor factorization, such as CANDECOMP/PARAFAC (CP), tensor train, or Tucker factorization [20]. -
Tensor Manipulation in GPL Maxima
Tensor Manipulation in GPL Maxima Viktor Toth http://www.vttoth.com/ February 1, 2008 Abstract GPL Maxima is an open-source computer algebra system based on DOE-MACSYMA. GPL Maxima included two tensor manipulation packages from DOE-MACSYMA, but these were in various states of disrepair. One of the two packages, CTENSOR, implemented component-based tensor manipulation; the other, ITENSOR, treated tensor symbols as opaque, manipulating them based on their index properties. The present paper describes the state in which these packages were found, the steps that were needed to make the packages fully functional again, and the new functionality that was implemented to make them more versatile. A third package, ATENSOR, was also implemented; fully compatible with the identically named package in the commercial version of MACSYMA, ATENSOR implements abstract tensor algebras. 1 Introduction GPL Maxima (GPL stands for the GNU Public License, the most widely used open source license construct) is the descendant of one of the world’s first comprehensive computer algebra systems (CAS), DOE-MACSYMA, developed by the United States Department of Energy in the 1960s and the 1970s. It is currently maintained by 18 volunteer developers, and can be obtained in source or object code form from http://maxima.sourceforge.net/. Like other computer algebra systems, Maxima has tensor manipulation capability. This capability was developed in the late 1970s. Documentation is scarce regarding these packages’ origins, but a select collection of e-mail messages by various authors survives, dating back to 1979-1982, when these packages were actively maintained at M.I.T. When this author first came across GPL Maxima, the tensor packages were effectively non-functional. -
Fast and Scalable Polynomial Kernels Via Explicit Feature Maps *
Fast and Scalable Polynomial Kernels via Explicit Feature Maps * Ninh Pham Rasmus Pagh IT University of Copenhagen IT University of Copenhagen Copenhagen, Denmark Copenhagen, Denmark [email protected] [email protected] ABSTRACT data space into high-dimensional feature space, where each Approximation of non-linear kernels using random feature coordinate corresponds to one feature of the data points. In mapping has been successfully employed in large-scale data that space, one can perform well-known data analysis al- analysis applications, accelerating the training of kernel ma- gorithms without ever interacting with the coordinates of chines. While previous random feature mappings run in the data, but rather by simply computing their pairwise in- O(ndD) time for n training samples in d-dimensional space ner products. This operation can not only avoid the cost and D random feature maps, we propose a novel random- of explicit computation of the coordinates in feature space ized tensor product technique, called Tensor Sketching, for but also handle general types of data (such as numeric data, approximating any polynomial kernel in O(n(d + D log D)) symbolic data). time. Also, we introduce both absolute and relative error While kernel methods have been used successfully in a va- bounds for our approximation to guarantee the reliability riety of data analysis tasks, their scalability is a bottleneck. of our estimation algorithm. Empirically, Tensor Sketching Kernel-based learning algorithms usually scale poorly with achieves higher accuracy and often runs orders of magni- the number of the training samples (a cubic running time tude faster than the state-of-the-art approach for large-scale and quadratic storage for direct methods). -
Learning-Based Frequency Estimation Algorithms
Published as a conference paper at ICLR 2019 LEARNING-BASED FREQUENCY ESTIMATION ALGORITHMS Chen-Yu Hsu, Piotr Indyk, Dina Katabi & Ali Vakilian Computer Science and Artificial Intelligence Lab Massachusetts Institute of Technology Cambridge, MA 02139, USA fcyhsu,indyk,dk,[email protected] ABSTRACT Estimating the frequencies of elements in a data stream is a fundamental task in data analysis and machine learning. The problem is typically addressed using streaming algorithms which can process very large data using limited storage. Today’s streaming algorithms, however, cannot exploit patterns in their input to improve performance. We propose a new class of algorithms that automatically learn relevant patterns in the input data and use them to improve its frequency estimates. The proposed algorithms combine the benefits of machine learning with the formal guarantees available through algorithm theory. We prove that our learning-based algorithms have lower estimation errors than their non-learning counterparts. We also evaluate our algorithms on two real-world datasets and demonstrate empirically their performance gains. 1.I NTRODUCTION Classical algorithms provide formal guarantees over their performance, but often fail to leverage useful patterns in their input data to improve their output. On the other hand, deep learning models are highly successful at capturing and utilizing complex data patterns, but often lack formal error bounds. The last few years have witnessed a growing effort to bridge this gap and introduce al- gorithms that can adapt to data properties while delivering worst case guarantees. Deep learning modules have been integrated into the design of Bloom filters (Kraska et al., 2018; Mitzenmacher, 2018), caching algorithms (Lykouris & Vassilvitskii, 2018), graph optimization (Dai et al., 2017), similarity search (Salakhutdinov & Hinton, 2009; Weiss et al., 2009) and compressive sensing (Bora et al., 2017). -
Polynomial Tensor Sketch for Element-Wise Function of Low-Rank Matrix
Polynomial Tensor Sketch for Element-wise Function of Low-Rank Matrix Insu Han 1 Haim Avron 2 Jinwoo Shin 3 1 Abstract side, we obtain a o(n2)-time approximation scheme of f (A)x ≈ T T >x for an arbitrary vector x 2 n due This paper studies how to sketch element-wise U V R to the associative property of matrix multiplication, where functions of low-rank matrices. Formally, given the exact computation of f (A)x requires the complexity low-rank matrix A = [A ] and scalar non-linear ij of Θ(n2). function f, we aim for finding an approximated low-rank representation of the (possibly high- The matrix-vector multiplication f (A)x or the low-rank > rank) matrix [f(Aij)]. To this end, we propose an decomposition f (A) ≈ TU TV is useful in many machine efficient sketching-based algorithm whose com- learning algorithms. For example, the Gram matrices of plexity is significantly lower than the number of certain kernel functions, e.g., polynomial and radial basis entries of A, i.e., it runs without accessing all function (RBF), are element-wise matrix functions where entries of [f(Aij)] explicitly. The main idea un- the rank is the dimension of the underlying data. Such derlying our method is to combine a polynomial matrices are the cornerstone of so-called kernel methods approximation of f with the existing tensor sketch and the ability to multiply the Gram matrix to a vector scheme for approximating monomials of entries suffices for most kernel learning. The Sinkhorn-Knopp of A. -
Electromagnetic Fields from Contact- and Symplectic Geometry
ELECTROMAGNETIC FIELDS FROM CONTACT- AND SYMPLECTIC GEOMETRY MATIAS F. DAHL Abstract. We give two constructions that give a solution to the sourceless Maxwell's equations from a contact form on a 3-manifold. In both construc- tions the solutions are standing waves. Here, contact geometry can be seen as a differential geometry where the fundamental quantity (that is, the con- tact form) shows a constantly rotational behaviour due to a non-integrability condition. Using these constructions we obtain two main results. With the 3 first construction we obtain a solution to Maxwell's equations on R with an arbitrary prescribed and time independent energy profile. With the second construction we obtain solutions in a medium with a skewon part for which the energy density is time independent. The latter result is unexpected since usually the skewon part of a medium is associated with dissipative effects, that is, energy losses. Lastly, we describe two ways to construct a solution from symplectic structures on a 4-manifold. One difference between acoustics and electromagnetics is that in acoustics the wave is described by a scalar quantity whereas an electromagnetics, the wave is described by vectorial quantities. In electromagnetics, this vectorial nature gives rise to polar- isation, that is, in anisotropic medium differently polarised waves can have different propagation and scattering properties. To understand propagation in electromag- netism one therefore needs to take into account the role of polarisation. Classically, polarisation is defined as a property of plane waves, but generalising this concept to an arbitrary electromagnetic wave seems to be difficult. To understand propaga- tion in inhomogeneous medium, there are various mathematical approaches: using Gaussian beams (see [Dah06, Kac04, Kac05, Pop02, Ral82]), using Hadamard's method of a propagating discontinuity (see [HO03]) and using microlocal analysis (see [Den92]). -
Automated Operation Minimization of Tensor Contraction Expressions in Electronic Structure Calculations
Automated Operation Minimization of Tensor Contraction Expressions in Electronic Structure Calculations Albert Hartono,1 Alexander Sibiryakov,1 Marcel Nooijen,3 Gerald Baumgartner,4 David E. Bernholdt,6 So Hirata,7 Chi-Chung Lam,1 Russell M. Pitzer,2 J. Ramanujam,5 and P. Sadayappan1 1 Dept. of Computer Science and Engineering 2 Dept. of Chemistry The Ohio State University, Columbus, OH, 43210 USA 3 Dept. of Chemistry, University of Waterloo, Waterloo, Ontario N2L BG1, Canada 4 Dept. of Computer Science 5 Dept. of Electrical and Computer Engineering Louisiana State University, Baton Rouge, LA 70803 USA 6 Computer Sci. & Math. Div., Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA 7 Quantum Theory Project, University of Florida, Gainesville, FL 32611 USA Abstract. Complex tensor contraction expressions arise in accurate electronic struc- ture models in quantum chemistry, such as the Coupled Cluster method. Transfor- mations using algebraic properties of commutativity and associativity can be used to significantly decrease the number of arithmetic operations required for evalua- tion of these expressions, but the optimization problem is NP-hard. Operation mini- mization is an important optimization step for the Tensor Contraction Engine, a tool being developed for the automatic transformation of high-level tensor contraction expressions into efficient programs. In this paper, we develop an effective heuristic approach to the operation minimization problem, and demonstrate its effectiveness on tensor contraction expressions for coupled cluster equations. 1 Introduction Currently, manual development of accurate quantum chemistry models is very tedious and takes an expert several months to years to develop and debug. The Tensor Contrac- tion Engine (TCE) [2, 1] is a tool that is being developed to reduce the development time to hours/days, by having the chemist specify the computation in a high-level form, from which an efficient parallel program is automatically synthesized. -
The Riemann Curvature Tensor
The Riemann Curvature Tensor Jennifer Cox May 6, 2019 Project Advisor: Dr. Jonathan Walters Abstract A tensor is a mathematical object that has applications in areas including physics, psychology, and artificial intelligence. The Riemann curvature tensor is a tool used to describe the curvature of n-dimensional spaces such as Riemannian manifolds in the field of differential geometry. The Riemann tensor plays an important role in the theories of general relativity and gravity as well as the curvature of spacetime. This paper will provide an overview of tensors and tensor operations. In particular, properties of the Riemann tensor will be examined. Calculations of the Riemann tensor for several two and three dimensional surfaces such as that of the sphere and torus will be demonstrated. The relationship between the Riemann tensor for the 2-sphere and 3-sphere will be studied, and it will be shown that these tensors satisfy the general equation of the Riemann tensor for an n-dimensional sphere. The connection between the Gaussian curvature and the Riemann curvature tensor will also be shown using Gauss's Theorem Egregium. Keywords: tensor, tensors, Riemann tensor, Riemann curvature tensor, curvature 1 Introduction Coordinate systems are the basis of analytic geometry and are necessary to solve geomet- ric problems using algebraic methods. The introduction of coordinate systems allowed for the blending of algebraic and geometric methods that eventually led to the development of calculus. Reliance on coordinate systems, however, can result in a loss of geometric insight and an unnecessary increase in the complexity of relevant expressions. Tensor calculus is an effective framework that will avoid the cons of relying on coordinate systems. -
Appendix a Relations Between Covariant and Contravariant Bases
Appendix A Relations Between Covariant and Contravariant Bases The contravariant basis vector gk of the curvilinear coordinate of uk at the point P is perpendicular to the covariant bases gi and gj, as shown in Fig. A.1.This contravariant basis gk can be defined as or or a gk g  g ¼  ðA:1Þ i j oui ou j where a is the scalar factor; gk is the contravariant basis of the curvilinear coordinate of uk. Multiplying Eq. (A.1) by the covariant basis gk, the scalar factor a results in k k ðgi  gjÞ: gk ¼ aðg : gkÞ¼ad ¼ a ÂÃk ðA:2Þ ) a ¼ðgi  gjÞ : gk gi; gj; gk The scalar triple product of the covariant bases can be written as pffiffiffi a ¼ ½¼ðg1; g2; g3 g1  g2Þ : g3 ¼ g ¼ J ðA:3Þ where Jacobian J is the determinant of the covariant basis tensor G. The direction of the cross product vector in Eq. (A.1) is opposite if the dummy indices are interchanged with each other in Einstein summation convention. Therefore, the Levi-Civita permutation symbols (pseudo-tensor components) can be used in expression of the contravariant basis. ffiffiffi p k k g g ¼ J g ¼ðgi  gjÞ¼Àðgj  giÞ eijkðgi  gjÞ eijkðgi  gjÞ ðA:4Þ ) gk ¼ pffiffiffi ¼ g J where the Levi-Civita permutation symbols are defined by 8 <> þ1ifði; j; kÞ is an even permutation; eijk ¼ > À1ifði; j; kÞ is an odd permutation; : A:5 0ifi ¼ j; or i ¼ k; or j ¼ k ð Þ 1 , e ¼ ði À jÞÁðj À kÞÁðk À iÞ for i; j; k ¼ 1; 2; 3 ijk 2 H. -
Low-Rank Pairwise Alignment Bilinear Network for Few-Shot Fine
JOURNAL OF LATEX CLASS FILES, VOL. XX, NO. X, JUNE 2019 1 Low-Rank Pairwise Alignment Bilinear Network For Few-Shot Fine-Grained Image Classification Huaxi Huang, Student Member, IEEE, Junjie Zhang, Jian Zhang, Senior Member, IEEE, Jingsong Xu, Qiang Wu, Senior Member, IEEE Abstract—Deep neural networks have demonstrated advanced abilities on various visual classification tasks, which heavily rely on the large-scale training samples with annotated ground-truth. Slot Alaskan Dog However, it is unrealistic always to require such annotation in h real-world applications. Recently, Few-Shot learning (FS), as an attempt to address the shortage of training samples, has made significant progress in generic classification tasks. Nonetheless, it Insect Husky Dog is still challenging for current FS models to distinguish the subtle differences between fine-grained categories given limited training Easy to Recognise A Little Hard to Classify data. To filling the classification gap, in this paper, we address Lion Audi A5 the Few-Shot Fine-Grained (FSFG) classification problem, which focuses on tackling the fine-grained classification under the challenging few-shot learning setting. A novel low-rank pairwise Piano Audi S5 bilinear pooling operation is proposed to capture the nuanced General Object Recognition with Single Sample Fine-grained Object Recognition with Single Sample differences between the support and query images for learning an effective distance metric. Moreover, a feature alignment layer Fig. 1. An example of general one-shot learning (Left) and fine-grained one- is designed to match the support image features with query shot learning (Right). For general one-shot learning, it is easy to learn the ones before the comparison. -
Gicheru3012018jamcs43211.Pdf
Journal of Advances in Mathematics and Computer Science 30(1): 1-15, 2019; Article no.JAMCS.43211 ISSN: 2456-9968 (Past name: British Journal of Mathematics & Computer Science, Past ISSN: 2231-0851) Decomposition of Riemannian Curvature Tensor Field and Its Properties James Gathungu Gicheru1* and Cyrus Gitonga Ngari2 1Department of Mathematics, Ngiriambu Girls High School, P.O.Box 46-10100, Kianyaga, Kenya. 2Department of Mathematics, Computing and Information Technology, School of Pure and Applied Sciences, University of Embu, P.O.Box 6-60100, Embu, Kenya. Authors’ contributions This work was carried out in collaboration between both authors. Both authors read and approved the final manuscript. Article Information DOI: 10.9734/JAMCS/2019/43211 Editor(s): (1) Dr. Dragos-Patru Covei, Professor, Department of Applied Mathematics, The Bucharest University of Economic Studies, Piata Romana, Romania. (2) Dr. Sheng Zhang, Professor, Department of Mathematics, Bohai University, Jinzhou, China. Reviewers: (1) Bilal Eftal Acet, Adıyaman University, Turkey. (2) Çiğdem Dinçkal, Çankaya University, Turkey. (3) Alexandre Casassola Gonçalves, Universidade de São Paulo, Brazil. Complete Peer review History: http://www.sciencedomain.org/review-history/27899 Received: 07 July 2018 Accepted: 22 November 2018 Original Research Article Published: 21 December 2018 _______________________________________________________________________________ Abstract Decomposition of recurrent curvature tensor fields of R-th order in Finsler manifolds has been studied by B. B. Sinha and G. Singh [1] in the publications del’ institute mathematique, nouvelleserie, tome 33 (47), 1983 pg 217-220. Also Surendra Pratap Singh [2] in Kyungpook Math. J. volume 15, number 2 December, 1975 studied decomposition of recurrent curvature tensor fields in generalised Finsler spaces.