# 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 >>

# “Half Precision” 16-bit Floating Point Arithmetic5

Posted by Cleve Moler,

The floating point arithmetic format that requires only 16 bits of storage is becoming increasingly popular. Also known as half precision or binary16, the format is useful when memory is a scarce resource.... read more >>

# A Roman Numeral Object, with Arithmetic, Matrices and a Clock3

Posted by Cleve Moler,

A MATLAB object for arithmetic with Roman numerals provides an example of object oriented programming. I had originally intended this as my April Fools post, but I got fascinated and decided to make it the subject of a legitimate article.... read more >>

# Bank Format and Metric Socket Wrenches2

Posted by Cleve Moler,

A report about a possible bug in format bank and a visit to a local hardware store made me realize that doing decimal arithmetic with binary floating point numbers is like tightening a European bolt with an American socket wrench.... read more >>

# My Erdös Number and My Trump Number3

Posted by Cleve Moler,

I've long known that my Erdös Number is 3. This means that the length of the path on the graph of academic coauthorship between me and mathematician Paul Erdös is 3. Somewhat to my surprise, I recently discovered that I can also trace a chain of coauthorship to Donald J. Trump. My Trump number is 5.... read more >>

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