2-pivot quicksort This posting on the Java core library mailing list proposes to replace the current quicksort with a new, 2-pivot quicksort. Ordinary quicksort in Haskell looks something like this: quicksort [] = [] quicksort (pivot:rest) = quicksort [x| x ← rest, x ≤ pivot] ++ [pivot] ++ quicksort [x| x ← rest, x > [...]
So, I thought it would be a fun idea for my first ever Lisp/Scheme program to implement Alan Turing’s original a-machines from his paper, On Computable Numbers, with an Application to the Entscheidungsproblem (paper available to public). Fun? Oh, I hadn’t any idea… Preamble; choice of implementation I decided to go with the latest and [...]
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Posted 10 August 2009
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Tagged: code, debugging, Functional programming, ikarus, machine, Programming, recursion, scheme, silly, theory, turing, universal, ypsilon
Argh #include <stdio.h> #include <math.h> #include <fenv.h> int main () { // don’t set rounding here double ten0 = sin(pow(10.0,22)); fesetround(FE_DOWNWARD); double ten1 = sin(pow(10.0,22)); fesetround(FE_UPWARD); double ten2 = sin(pow(10.0,22)); fesetround(FE_TONEAREST); double ten3 = sin(pow(10.0,22)); fesetround(FE_TOWARDZERO); double ten4 = sin(pow(10.0,22)); printf( "Default: %f\n" "Downward: %f\n" "Upward: %f\n" "ToNearest: %f\n" [...]
I was looking for some standard symbols to represent the Control key and the Alt key, and couldn’t find one until I came across ISO/IEC 9995-7. Because I had much trouble finding a free copy of the document on the ’Net, I have made a table of the symbols and their functions below. I have [...]
