# How Far Apart Are Two Random Points in a Square?

Posted by Cleve Moler,

How far apart can you expect two points chosen at random in the unit square to be? I found this problem on the YouTube channel maintained by Presh Talwalkar, Mind Your Decisions. He correctly calls it a very hard puzzle. At first, I guessed the answer might be $1/2$. But the correct answer is more interesting than that.... read more >>

# A Logo Zoetrope

Posted by Cleve Moler,

A quick post to point my readers to Ned Gulley's post in MATLAB Community, A Galloping Logo Zoetrope. Don't know what a Zoetrope is? Ned explains.... read more >>

Posted by Cleve Moler,

Do not get involved in a bar bet with Brad Efron and his dice until you have read this.... read more >>

# C^5, Cleve’s Corner Collection Card Catalog2

Posted by Cleve Moler,

I have been writing books, programs, newsletter columns and blogs since 1990. I have now collected all of this material into one repository. Cleve's Corner Collection consists of 458 "documents", all available on the internet. There are... read more >>

# Levenshtein Edit Distance Between Strings

Posted by Cleve Moler,

How can you measure the distance between two words? How can you find the closest match to a word in a list of words? The Levenshtein distance between two strings is the number of single character deletions, insertions, or substitutions required to transform one string into the other. This is also known as the edit distance.... read more >>

# Latent Semantic Indexing, SVD, and Zipf’s Law5

Posted by Cleve Moler,

Latent Semantic Indexing, LSI, uses the Singular Value Decomposition of a term-by-document matrix to represent the information in the documents in a manner that facilitates responding to queries and other information retrieval tasks. I set out to learn for myself how LSI is implemented. I am finding that it is harder than I thought.... read more >>

# What is the Condition Number of a Matrix?1

Posted by Cleve Moler,

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

# Householder Seminar HHXX on Numerical Linear Algebra2

Posted by Cleve Moler,

The Householder meetings on Numerical Linear Algebra have been held roughly every three years since 1961. The twentieth, with the logo HHXX, was held June 18th through 23rd at Virginia Tech in Blacksburg, Virginia. I've been to 17 of the meetings. They have been an important part of my professional life and I've written Cleve's Corner articles and blog posts about them, MathWorks News & Notes, and Householder XIX.... read more >>

# Quadruple Precision, 128-bit Floating Point Arithmetic9

Posted by Cleve Moler,

The floating point arithmetic format that occupies 128 bits of storage is known as binary128 or quadruple precision. This blog post describes an implementation of quadruple precision programmed entirely in the MATLAB language.... read more >>

These postings are the author's and don't necessarily represent the opinions of MathWorks.