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Posts 71 - 80 of 102

Results for: Numerical Analysis

19 Dubious Ways to Compute the Zeros of a Polynomial 2

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".... read more >>

Modernization of Numerical Integration, From Quad to Integral

The MATLAB functions for the numerical evaluation of integrals has evolved from quad, through quadl and quadgk, to today's integral. ... read more >>

Fractal Global Behavior of Newton’s Method

When the starting point of Newton's method is not close to a zero of the function, the global behavior can appear to be unpredictable. Contour plots of iteration counts to convergence from a region of starting points in the complex plane generate thought-provoking fractal images. Our examples employ the subject of two recent posts, the historic cubic $x^3-2x-5$. ... read more >>

Testing Zero Finders 2

Use the historic cubic polynomial $x^3 - 2x - 5$ to test a few zero-finding algorithms. ... read more >>

A Historic Cubic 2

The cubic polynomial $x^3 - 2x - 5$ has a unique place in the history of numerical methods.... read more >>

Zeroin, Part 3: MATLAB Zero Finder, FZERO

MATLAB adds capability to search for an interval with a sign change.... read more >>

Zeroin, Part 2: Brent’s Version 2

Richard Brent's improvements to Dekker's zeroin algorithm, published in 1971, made it faster, safer in floating point arithmetic, and guaranteed not to fail. ... read more >>

Zeroin, Part 1: Dekker’s Algorithm

Th. J. Dekker's zeroin algorithm from 1969 is one of my favorite algorithms. An elegant technique combining bisection and the secant method for finding a zero of a function of a real variable, it has become fzero in MATLAB today. This is the first of a three part series.... read more >>

Charles Lawson, 1931 – 2015

Chuck Lawson passed away in July at the age of 83. Chuck was one of the people who introduced me to computing and mathematical software. I worked for him at Caltech's Jet Propulsion Laboratory during the summers of 1961 and 1962, just before and after my first year in grad school.... read more >>

Trip Report: Trefethen Birthday Conference 4

"New Directions in Numerical Computation" was a conference in celebration of Nick Trefethen's 60th birthday held August 25-28 in the new Andrew Wiles building, which houses the Mathematical Institute of the University of Oxford.... read more >>

Posts 71 - 80 of 102