Methinks it is like a weasel: March 2009

Monday, March 30, 2009

C# weasel

Submitted by Robert Welbourn

http://www.welbourn.com/weasel/

Includes the source code, an installer and a screenshot.

The "cdesign proponentists" weasel


#!/usr/bin/env magic

Sunday, March 29, 2009

Tcl the weasel

Submitted by Eric Amundsen


#!/usr/bin/env tclsh
proc pick {{range 27}} {
 return [expr {int(rand() * $range)}]
} 

set alphabet " abcdefghijklmnopqrstuvwxyz"
for {set j 0} {$j < [string length $alphabet]} {incr j} {
  set ::[string index $alphabet $j] $j
}

proc calcOffspringScore {offspring} {
  set score 0
  for {set j 0} {$j < [string length $::target]} {incr j} {
    set score [expr {$score + abs([set ::[string index $::target $j]] - [set ::[string index $offspring $j]])}]
  }
  return $score
}

proc createOffspring {parent} {
  set splitPoint [pick [string length $parent]]
  set offspring [string range $parent 0 [expr {$splitPoint - 1}]]
  append offspring [string index $::alphabet [pick]]
  append offspring [string range $parent [expr {$splitPoint + 1}] end]
  return $offspring
}

proc breed {parent numOffspring} {
  set bestKid -1
  set bestScore 10000
  for {set j 0} {$j < $numOffspring} {incr j} {
    set kid [createOffspring $parent] 
    set kids($j) $kid
    set score [calcOffspringScore $kid]
    if {$bestScore > $score} {
       set bestKid $j
       set bestScore $score
     }
  }
  return $kids($bestKid)
}

if {[llength $argv] == 0} {
  puts "methink.tcl usage : 
methink.tcl <# offspring / gen> <(optional) target string>
default target => \"methinks it is like a weasle\"
target string can only include a-z lowercase and space"
  return
} elseif {[llength $argv] == 1} {
  set ::target "methinks it is like a weasle"
} else {
  set ::target [lindex $argv 1]
}

set numOffspring [lindex $argv 0]

set initString ""
for {set j 0} {$j < [string length $target]} {incr j} {
  append initString [string index $alphabet [pick]]
}

puts [set genString $initString]
for {set j 0} {$j < 10000000} {incr j} {
  puts [set genString [breed $genString $numOffspring]]
  if {$genString == $target} {
    puts "[incr j] generations"
    return
  }
}
puts "sorry, gave up after [incr j] generations"

Saturday, March 28, 2009

VBA Excel weasel

Submitted by Ian Rhile


Sub weasel()
'An Excel macro for Dawkin's weasel algorithm
gentarget = 0
mutationrate = 0.05
Sheets("Sheet1").Cells.ClearContents
target = "methinks it is like a weasel"
alphabet = "abcdefghijklmnopqrstuvwxyz "
'generate initial random string
For x = 1 To Len(target)
    y = Int(27 * Rnd + 1)
    seq = seq + Mid(alphabet, y, 1)
Next x
Sheets("Sheet1").Range("A1").Value = "original sequence:"
Sheets("Sheet1").Range("B1").Value = seq
Sheets("Sheet1").Range("A2").Value = "generation"
Sheets("Sheet1").Range("B2").Value = "original generational sequence"
Sheets("Sheet1").Range("C2").Value = "matches"
50 gen = gen + 1
Sheets("Sheet1").Cells(gen + 2, 1) = gen
Sheets("Sheet1").Cells(gen + 2, 2) = seq
maxfit = 0
maxfitseq = seq
For x = 1 To 100
    newseq = seq
    For u = 1 To Len(seq)
        If Rnd < mutationrate Then
            w = Int(27 * Rnd + 1)
            Mid(newseq, u, 1) = Mid(alphabet, w, 1)
        End If
    Next u
    Sheets("Sheet1").Cells(gen + 2, x + 4) = newseq
    fit = 0
    For t = 1 To Len(newseq)
        If Mid(target, t, 1) = Mid(newseq, t, 1) Then fit = fit + 1
    Next t
    If fit > maxfit Then
        maxfit = fit
        maxfitseq = x
    End If
Next x
Sheets("Sheet1").Cells(gen + 2, 3) = maxfit
    
seq = Sheets("Sheet1").Cells(gen + 2, maxfitseq + 4).Value
If gentarget > 0 And gen > gentarget Then GoTo 100
If seq = target Then
    If gentarget > 0 Then GoTo 50
    gentarget = gen + 100
End If
GoTo 50
100 End Sub