Communication-optimal parallel algorithm for strassen's matrix multiplication

Summary form only given. We propose a new distribution scheme for a parallel Strassen's matrix multiplication algorithm on heterogeneous clusters. In the heterogeneous clustering environment, appropriate data distribution is the most important factor for achieving maximum overall performance. However, Strassen's algorithm reduces the total operation count to about 7/8 times per one recursion and, hence, the recursion level has an effect on the total operation count. Thus, we need to consider not only load balancing but also the recursion level in Strassen's algorithm. Our scheme achieves both load balancing and reduction of the total operation count. As a result, we achieve a speedup of nearly 21.7% compared to the conventional parallel Strassen's algorithm in a heterogeneous clustering environment.

Prior implementations of Strassen's matrix multiplication algorithm on GPUs traded additional workspace in the form of global memory or registers for time. Although Strassen's algorithm offers a reduction in computational complexity as compared to the classical algorithm, the memory overhead associated with the algorithm limits its practical utility. While there were past attempts at reducing the memory footprint of Strassen's algorithm by compromising parallelism, no prior implementation, to our knowledge, was able to hide the workspace requirement successfully. This paper presents an implementation of Strassen's matrix multiplication in eUDA, titled Multi-Stage Memory Efficient Strassen (MSMES), that eliminates additional workspace requirements by reusing and recovering input matrices. MSMES organizes the steps involved in Strassen's algorithm into five stages where multiple steps in the same stage can be executed in parallel. Two additional stages are also discussed in the paper that allows the recovery of the input matrices. Unlike previous works, MSMES has no additional memory requirements irrespective of the level of recursion of Strassen's algorithm. Experiments performed with MSMES (with the recovery stages) on NVIDIA Tesla V100 GPU and NVIDIA GTX 1660ti GPU yielded higher compute performance and lower memory requirements as compared to the NVIDIA library function for double precision matrix multiplication, cublasDgemm.

We discuss a programming methodology based on the use of multilinear algebra to design and implement parallel algorithms for linear computations. In particular, we review techniques for implementing expressions involving the tensor product. We then show how the tensor product can be used to formulate Strassen's matrix multiplication algorithm. We report on our experience using this formulation and these techniques to implement a parallel version of Strassen's matrix multiplication algorithm on the Encore Multimax.

Strassen's algorithm for matrix multiplication gains its lower arithmetic complexity at the expense of reduced locality of reference, which makes it challenging to implement the algorithm efficiently on a modern machine with a hierarchical memory system. We report on an implementation of this algorithm that uses several unconventional techniques to make the algorithm memory-friendly. First, the algorithm internally uses a non- standard array layout known as Morton order that is based on a quad-tree decomposition of the matrix. Second, we dynamically select the recursion truncation point to minimize padding without affecting the performance of the algorithm, which we can do by virtue of the cache behavior of the Morton ordering. Each technique is critical for performance, and their combination as done in our code multiplies their effectiveness. Performance comparisons of our implementation with that of competing implementations show that our implementation often outperforms the alternative techniques (up to 25%). However, we also observe wide variability across platforms and across matrix sizes, indicating that at this time, no single implementation is a clear choice for all platforms or matrix sizes. We also note that the time required to convert matrices to/from Morton order is a noticeable amount of execution time (5% to 15%). Eliminating this overhead further reduces our execution time.

Comparisons of Gaussian elimination algorithms on a cray Y-MP

For many scientific applications, dense matrix multiplication is one of the most important and computation intensive linear algebra operations. An efficient matrix multiplication on high performance and parallel computers requires optimizations on how matrices are decomposed and exchanged between computational nodes to reduce communication and synchronization overhead, as well as to efficiently exploit the memory hierarchy within a node to improve both spatial and temporal data locality. In this paper, we presented our studies of performance, cache behavior, and energy efficiency of multiple parallel matrix multiplication algorithms on a multicore desktop computer and a medium-size shared memory machine, both being considered as referenced sizes of nodes to create a medium- and largescale computational clusters for high performance computing used in industry and national laboratories. Our results highlight both the performance and energy efficiencies, and also provide implications on the memory and resources pressures of those algorithms. We hope this could help users choose the appropriate implementations according to their specific data sets when composing larger-scale scientific applications that use parallel matrix multiplication kernels on a node.

Strassen's algorithm is an efficient method for multiplying large matrices. We explore various ways of mapping Strassen's algorithm into reconfigurable hardware that contains one or more customisable instruction processors. Our approach has been implemented using Nios processors with custom instructions and with custom-designed coprocessors, taking advantage of the additional logic and memory blocks available on a reconfigurable platform.

We present efficient parallel matrix multiplication algorithms for linear arrays with reconfigurable pipelined bus systems (LARPBS). Such systems are able to support a large volume of parallel communication of various patterns in constant time. An LARPBS can also be reconfigured into many independent subsystems and, thus, is able to support parallel implementations of divide-and-conquer computations like Strassen's algorithm. The main contributions of the paper are as follows. We develop five matrix multiplication algorithms with varying degrees of parallelism on the LARPBS computing model; namely, MM/sub 1/, MM/sub 2/, MM/sub 3/, and compound algorithms C/sub 1/(/spl epsiv/)and C/sub 2/(/spl delta/). Algorithm C/sub 1/(/spl epsiv/) has adjustable time complexity in sublinear level. Algorithm C/sub 2/(/spl delta/) implies that it is feasible to achieve sublogarithmic time using /spl sigma/(N/sup 3/) processors for matrix multiplication on a realistic system. Algorithms MM/sub 3/, C/sub 1/(/spl epsiv/), and C/sub 2/(/spl delta/) all have o(/spl Nscr//sup 3/) cost and, hence, are very processor efficient. Algorithms MM/sub 1/, MM/sub 3/, and C/sub 1/(/spl epsiv/) are general-purpose matrix multiplication algorithms, where the array elements are in any ring. Algorithms MM/sub 2/ and C/sub 2/(/spl delta/) are applicable to array elements that are integers of bounded magnitude, or floating-point values of bounded precision and magnitude, or Boolean values. Extension of algorithms MM/sub 2/ and C/sub 2/(/spl delta/) to unbounded integers and reals are also discussed.

Describes the important role of decomposition strategy in parallel computing, and its influence is illustrated with the example of a very frequently used parallel algorithm for matrix multiplication. On the basis of the performed analysis of the parallel computers used worldwide divides them into the two basic groups which are considered from the programmer‐developer point of view to be very different. They also introduce the typical principal structures for both these groups of parallel computers and also their models. The paper then in an illustrative way describes the development of concrete parallel algorithm for matrix multiplication on various parallel systems. For each individual practical implementation of matrix multiplication there is introduced the derivation of its calculation complexity. The individual ways of developing parallel matrix multiplication and their implementations are compared, analysed and discussed from the point of view of the programmer‐developer and user. The very important role of the decomposition strategies that are mainly of the class of asynchronous parallel computers is highlighted.

There are many ways to hide information or transmission of information secretly. In this sense steganography is the best part of sending information secretly. The technology has certainly been the topic of widespread discussion among the IT community. Steganography, like watermarking and fingerprinting is a branch of science to hide information but, unlike watermarking and fingerprinting, steganogaraphy is the art ofwriting message or information in such a way that no one apart suitable recipient knows the meaning of the message or information. There are many techniques to performsteganography on electronic media, most notably audio and image files. The outcome of thispaper is to generate a cross platformthat can effectively hide a message inside a digitalimage file. We are presenting a technique which works by changing a few pixel color value at selected pixel in the image. We divide the image into blocks and in each block, the pixels are selected using HIOP (Higher Intensity of Pixel) algorithm, based on consideration the criteria of color intensity on image. To increase the security level, we create distribution in selected pixels whit using strassen multiplication in each block. Also, when retrieving a message for avoid repeating process which hidden text storage and speed up information retrieval, we save address of selected pixel. It is also, try not to degrade image quality and as far as possible does not change the image size. Key words: Steganography, watermarking, fingerprinting, HIOP, strassen multiplication, color intensity.

The communication cost of algorithms (also known as I/O-complexity) is shown to be closely related to the expansion properties of the corresponding computation graphs. We demonstrate this on Strassen's and other fast matrix multiplication algorithms, and obtain first lower bounds on their communication costs. In the sequential case, where the processor has a fast memory of size $M$, too small to store three $n$-by-$n$ matrices, the lower bound on the number of words moved between fast and slow memory is, for many of the matrix multiplication algorithms, $\Omega((\frac{n}{\sqrt M})^{\omega_0}\cdot M)$, where $\omega_0$ is the exponent in the arithmetic count (e.g., $\omega_0 = \lg 7$ for Strassen, and $\omega_0 = 3$ for conventional matrix multiplication). With $p$ parallel processors, each with fast memory of size $M$, the lower bound is $p$ times smaller. These bounds are attainable both for sequential and for parallel algorithms and hence optimal. These bounds can also be attained by many fast algorithms in linear algebra (e.g., algorithms for LU, QR, and solving the Sylvester equation).

In order to solve the problem of parallel algorithm for matrix multiplication,according to the characteristic of Biswapped network,a parallel algorithm for matrix multiplication based on Biswapped network was developed. The algorithm is simple in operation and easy to implement by using a new suggested mapping scheme. It is showed in theoretic analysis and experimental test,the proposed algorithm equals to Cannon's approximately.

Utilizing all CPU cores available for numerical computations is a topic of considerable interest in HPC. This paper analyzes and compares four different parallel algorithms for matrix multiplication without block partitioning using OpenMP. The comparison of the algorithms is based on the achieved speed, memory bandwidth and efficient use of the cache of the algorithms.

The author presents a new parallel matrix multiplication algorithm on distributed memory concurrent computers, which is fast and scalable, and whose performance is independent of data distribution on processors, and calls it DIMMA (Distribution-Independent Matrix Multiplication Algorithm). The algorithm is based on two new ideas; it uses a modified pipelined communication scheme to overlap computation and communication effectively and exploits the LCM block concept to obtain the maximum performance of the sequential BLAS routine in each processor even when the block size is very small as well as very large. The algorithm is implemented and compared with SUMMA on the Intel Paragon computer.

This paper presents a natural and efficient implementation for the classical broadcast message passing routine which optimizes performance of Ethernet based clusters. A simple algorithm for parallel matrix multiplication is specifically designed to take advantage of both, parallel computing facilities (CPUs) provided by clusters, and optimized performance of broadcast messages on Ethernet based clusters. Also, this simple parallel algorithm proposed for matrix multiplication takes into account the possibly heterogenous computing hardware and maintains a balanced workload of computers according to their relative computing power. Performance tests are presented on a heterogenous cluster as well as on a homogeneous cluster, where it is compared with the parallel matrix multiplication provided by the ScaLAPACK library. Another simple parallel algorithm is proposed for LU matrix factorization (a general method to solve dense systems of equations) following the same guidelines used for the parallel matrix multiplication algorithm. Some performance tests are presented over a homogenous cluster.