# Closest Pair of Points Problem

The Closest Pair of Points problem is a standard topic in an algorithms course today, but when I taught such a course fifty years ago, the algorithm was not yet known.... 更多内容 >>

# A Matrix for the New HPL-AI Benchmark2

My colleagues are looking for a matrix to be used in a new benchmark. They've come to the right place.... 更多内容 >>

# Benchmarking a GPU5

I recently acquired a GPU, a graphics processing unit. It's called a GPU because such processors were originally intended to speed up graphics. But MATLAB uses it to speed up computation. Let's see how the gpuArray object benchmarks on my machine. I have been doing computer benchmarks for years. I like to do profiles where I vary the size of a task and see how the amount of memory required affects performance. I always learn something unexpected when I do these profiles. Ben Todoroff is on the MathWorks Parallel Processing team. Last year he contributed #34080, gpuBench to the MATLAB Central File Exchange. He has been able to compare several different GPUs. I am going to consider the performance of only one GPU, but in more detail. Important note. This is only about double precision. Single precision is another story. ... 更多内容 >>

# What is the Condition Number of a Matrix?1

A couple of questions in comments on recent blog posts have prompted me to discuss matrix condition numbers.... 更多内容 >>

# 19 Dubious Ways to Compute the Zeros of a Polynomial2

During the SIAM Annual Meeting this summer in Boston there will be a special minisymposium Wednesday afternoon, July 13, honoring Charlie Van Loan, who is retiring at Cornell. (I use "at" because he's not leaving Ithaca.) I will give a talk titled "19 Dubious Way to Compute the Zeros of a Polynomial", following in the footsteps of the paper about the matrix exponential that Charlie and I wrote in 1978 and updated 25 years later. I really don't have 19 ways to compute polynomial zeros, but then I only have a half hour for my talk. Most of the methods have been described previously in this blog. Today's post is mostly about "roots".... 更多内容 >>

# Trip Report: SuperComputing 2015

SC15, the International Conference for High Performance Computing, Networking, Storage and Analysis, was held in Austin, Texas, last week, November 15 through 20. This is the largest trade show and conference that MathWorks participates in each year.... 更多内容 >>

# The Ziggurat Random Normal Generator

This is the third in a multi-part series on the MATLAB random number generators. MATLAB has used variants of George Marsaglia's ziggurat algorithm to generate normally distributed random numbers for almost twenty years. ... 更多内容 >>

# The LINPACK Benchmark

By reaching 33.86 petaflops on the LINPACK Benchmark, China's Tianhe-2 supercomputer has just become the world's fastest computer. The technical computing community thinks of LINPACK not as a matrix software library, but as a benchmark. In that role LINPACK has some attractive aspects, but also some undesirable features.... 更多内容 >>