Category Archives: Floating Point

Floating-Point Determinism

Posted on July 16, 2013 by brucedawson

Is IEEE floating-point math deterministic? Will you always get the same results from the same inputs? The answer is an unequivocal “yes”. Unfortunately the answer is also an unequivocal “no”. I’m afraid you will need to clarify your question. My … Continue reading →

Posted in Floating Point, Visual Studio | Tagged | 65 Comments

Float Precision Revisited: Nine Digit Float Portability

Posted on February 7, 2013 by brucedawson

Last year I pointed out that float variables can be converted to text and then back to the same binary value using printf(“%1.8e”). You can also use %.9g for more compact results. I also supplied a test program that used … Continue reading →

Posted in Floating Point | Tagged , , , , | 17 Comments

Top Eight Entertaining Blog Facts for 2012

Posted on January 3, 2013 by brucedawson

The end of the year is a traditional time for lists and I thought I’d do a post just to summarize the most interesting or surprising things that I discovered while writing this blog during 2012.

Posted in Bugs, Floating Point, Performance, Programming | Tagged , , , | 1 Comment

Game Developer Magazine Floating Point

Posted on September 9, 2012 by brucedawson

This is for references, code examples, and discussion regarding the floating-point article in the October 2012 Game Developer Magazine.

Posted in Floating Point | Tagged | 3 Comments

Doubles are not floats, so don’t compare them

Posted on June 26, 2012 by brucedawson

I’ve seen a few online discussions linking to my Comparing Floating Point Numbers page for misguided reasons and I wanted to discuss those reasons to help people understand why throwing epsilons at the problem without understanding the situation is a … Continue reading →

Posted in Floating Point, Programming | Tagged , , , , | 24 Comments

Floating-Point Poetry

Posted on June 3, 2012 by brucedawson

I gave a talk at iFest on Saturday that briefly covered some performance and precision issues taken from my series of floating-point blog posts. My talk was after Ed Fries, who did a brilliant talk on art and constraints, centered … Continue reading →

Posted in Floating Point | Tagged , | 3 Comments

That’s Not Normal–the Performance of Odd Floats

Posted on May 20, 2012 by brucedawson

Denormals, NaNs, and infinities round out the set of standard floating-point values, and these important values can sometimes cause performance problems. The good news is, it’s getting better, and there are diagnostics you can use to watch for problems. In … Continue reading →

Posted in AltDevBlogADay, Floating Point, Performance, Programming | Tagged , , , , , | 21 Comments

Exceptional Floating Point

Posted on April 21, 2012 by brucedawson

Floating-point math has an answer for everything, but sometimes that’s not what you want. Sometimes instead of getting an answer to the question sqrt(-1.0) (it’s NaN) it’s better to know that your software is asking imaginary questions. The IEEE standard … Continue reading →

Posted in AltDevBlogADay, Floating Point, Programming | Tagged , , , , | 24 Comments

Floating-point complexities

Posted on April 5, 2012 by brucedawson

Binary floating-point math is complex and subtle. I’ve collected here a few of my favorite oddball facts about IEEE floating-point math, based on the articles so far in my floating-point series. The focus in this list is on float but … Continue reading →

Posted in AltDevBlogADay, Floating Point, Programming | Tagged , , , , , , , , | 15 Comments

Intermediate Floating-Point Precision

Posted on March 21, 2012 by brucedawson

Riddle me this Batman: how much precision are these calculations evaluated at? If you answered ‘double’ and ‘float’ then you score one point for youthful idealism, but zero points for correctness. The correct answer, for zero-idealism points and forty two … Continue reading →

Posted in AltDevBlogADay, Floating Point, Programming, Visual Studio | Tagged , , , , , | 43 Comments