This post is the December 26th entry in the 2014 English F# Blog Advent Calendar. Check out the other great posts from earlier in the month, or head over to the Japanese-language edition! Ho ho ho! It’s the day after Christmas, and hopefully everyone has some snazzy new toys to play with.  But just in case Santa left you a lump of coal (“… little Billy used mutable state this year …”), don’t pout, don’t cry, I’ve got you covered.  My gift for all the naughty F# developers out there: a mini-framework for[...]

Continuing the recent theme of awesome .NET development news, a blog post from Thursday by the .NET team provided more details on the platform's future, ".NET Core." The ensuing comment thread on Hacker News had some nice F# discussion.  One commenter, though, was not a huge fan, and in particular lamented perceived limitations in the F# … Continue reading Extending a 3rd-party API with F# units of measure →

Continuing the recent theme of awesome .NET development news, a blog post from Thursday by the .NET team provided more details on the platform’s future, “.NET Core.” The ensuing comment thread on Hacker News had some nice F# discussion.  One commenter, though, was not a huge fan, and in particular lamented perceived limitations in the F# units of measure feature: ...I tried to be excited about units of measure, but there isn't even a way to annotate third-party libraries...source Well that’s just nonsen[...]

A while back I came upon a seemingly not-too-difficult programming exercise: Define a recurrence  by Compute . This isn't too hard to code up, using perhaps a recursive function to represent . With normal double-precision floats, as increases, the result converges neatly toward 100. Super! Unfortunately, 100 is not even close to the right answer. This … Continue reading Muller's Recurrence - roundoff gone wrong →

A while back I came upon a seemingly not-too-difficult programming exercise: Define a recurrence \(x_n\) by $$f(y, z) = 108 - \frac{815 - 1500/z}{y}$$ $$x_0 = 4$$ $$x_1 = 4.25$$ $$x_i = f(x_{i-1}, x_{i-2})$$ Compute \(x_{30}\). This isn’t too hard to code up, using perhaps a recursive function to represent \(x_i\). With normal double-precision floats, as \(i\) increases, the result converges neatly toward 100. Super! Unfortunately, 100 is not even close to the right answer. This recurrence actually [...]