The multiplication of a sparse matrix by a dense vector is a centerpiece of scientific computing applications: it is the essential kernel for the solution of sparse linear systems and sparse eigenvalue problems by iterative methods. The efficient implementation of the sparse matrixvector multiplication is therefore crucial and has been the subject of an immense […]

September 9, 2015 by hgpu

While many of the architectural details of future exascale-class high performance computer systems are still a matter of intense research, there appears to be a general consensus that they will be strongly heterogeneous, featuring "standard" as well as "accelerated" resources. Today, such resources are available as multicore processors, graphics processing units (GPUs), and other accelerators […]

July 30, 2015 by hgpu

With the advent of parallel processing architectures and a steep increase in parallelism found among the recent applications, GPGPUs have gained attention with respect to their importance in the execution of these applications. In this document, we specifically analyze Sparse-Matrix Vector Multiplication(SPMV) across different architectures, libraries and matrix formats. The experimental platforms include but are […]

June 19, 2015 by hgpu

Sparse matrix-vector multiplication (SpMV) is a widely used kernel in scientific applications as well as data analytics. Many GPU implementations of SpMV have been proposed, proposing different sparse matrix representations. However, no sparse matrix representation is consistently superior, and the best representation varies for sparse matrices with different sparsity patterns. In this paper we study […]

June 16, 2015 by hgpu

Embedded languages are often compiled at application runtime; thus, embedded compile-time errors become application runtime errors. We argue that advanced type system features, such as GADTs and type families, play a crucial role in minimising such runtime errors. Specifically, a rigorous type discipline reduces runtime errors due to bugs in both embedded language applications and […]

June 14, 2015 by hgpu

Sparse matrix-vector multiplication (SpMV) is a core kernel in numerous applications, ranging from physics simulation and large-scale solvers to data analytics. Many GPU implementations of SpMV have been proposed, targeting several sparse representations and aiming at maximizing overall performance. No single sparse matrix representation is uniformly superior, and the best performing representation varies for sparse […]

June 14, 2015 by hgpu

We provide an efficient implementation of existing parameter synthesis techniques for stochastic systems modelled as continuous-time Markov chains (CTMCs). These techniques iteratively decompose the parameter space into its subspaces and approximate the satisfaction function that for any parameter values from the parameter space returns the probability of the formula being satisfied in the CTMC given […]

June 14, 2015 by hgpu

Sparse matrix-vector multiplication (SpMV) is a central building block for scientific software and graph applications. Recently, heterogeneous processors composed of different types of cores attracted much attention because of their flexible core configuration and high energy efficiency. In this paper, we propose a compressed sparse row (CSR) format based SpMV algorithm utilizing both types of […]

April 27, 2015 by hgpu

The present work is an analysis of the performance of the AXPY, DOT and SpMV functions using OpenCL. The code was tested on the NVIDIA Tesla S2050 GPU and Intel Xeon Phi 3120A coprocessor. Due to nature of the AXPY function, only two versions were implemented, the routine to be executed by the CPU and […]

April 27, 2015 by hgpu

Sparse matrix factorization involves a mix of regular and irregular computation, which is a particular challenge when trying to obtain high-performance on the highly parallel general-purpose computing cores available on graphics processing units (GPUs). We present a sparse multifrontal QR factorization method that meets this challenge, and is up to eleven times faster than a […]

April 25, 2015 by hgpu

General sparse matrix-matrix multiplication (SpGEMM) is a fundamental building block for numerous applications such as algebraic multigrid method (AMG), breadth first search and shortest path problem. Compared to other sparse BLAS routines, an efficient parallel SpGEMM implementation has to handle extra irregularity from three aspects: (1) the number of nonzero entries in the resulting sparse […]

April 23, 2015 by hgpu

This thesis, entitled "High Performance Computing for solving large sparse systems. Optical Diffraction Tomography as a case of study" investigates the computational issues related to the resolution of linear systems of equations which come from the discretization of physical models described by means of Partial Differential Equations (PDEs). These physical models are conceived for the […]

March 30, 2015 by hgpu