Edge Cases 83: Floating Point Numbers Are a Leaky Abstraction

Wolf Rentzsch talks to Andrew Pontious about floating point numbers: how they work, why they’re weird, and when you definitely shouldn’t use them (hint: mo money mo problems).

Links:

• George E. P. Box « Wikipedia
• Floating point numbers are a leaky abstraction « The Endeavour
• It’s a Unix system « YouTube
• Five Tips for Floating Point Programming « CodeProject
• Float « ridiculous_fish
• Floating-point unit « Wikipedia
• A Cryptography Tourist « Edge Cases
• What Every Computer Scientist Should Know About Floating-Point Arithmetic « Oracle Documentation
• An Interview with the Old Man of Floating-Point « Professor William Kahan’s web pages
• Binary-coded decimal « Wikipedia
• Arbitrary-precision arithmetic « Wikipedia
• DEC64: Decimal Floating Point
• General Decimal Arithmetic « speleotrove.com
• NSDecimal vs. NSDecimalNumber « coreplot-discuss Google Group

Rejected Episode Titles:

• You Bet Your Asset Catalog!
• All Models Are Wrong, Some Models Are Useful
• Imagine You’re on the Beach at a Resort
• Now, Imagine That You Go All Godzilla
• (Not the Spreadsheet)
• It’s Not a Trick Question, Although Maybe It Is
• This Was Science and This Was Truth
• Numbers! I Know This!
• Not Your First Floating Point Rodeo
• If We Went to School, We Probably Would Know That
• You’re in This Different World
• Because You’re a Graybeard
• You’ve Exhausted It
• There Are No Solutions, There Are Only Tradeoffs
• That’s a Lot of Zeroes to Say
• “Aren’t You a Compression Buff?” “It’s More of a Hobby”
• This Could Be a Very Long Episode
• Gradual Underflow
• You’ve Suffered Accuracy Loss
• Numerically Unsophisticated Programmers
• This False Sense of Security
• Then the Wave Comes in and Sweeps You in the Ocean
• “No One Really Cares About This Stuff” “Except You” “Even I…My Eyes Glaze Over”
• A Bunch of Decisions That Humans Had to Make
• Genetically Diverse
• We Can Pretty Much Thank Intel for It
• We’re Mentioning DEC Again
• The First Thing Some Joker Would Do
• Don’t Use Floating Point Numbers for Money
• Avoid Floating Point If You Can