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authormnicky <xmnicky@gmail.com>2013-11-05 10:59:48 +0100
committermnicky <xmnicky@gmail.com>2013-11-05 10:59:48 +0100
commitc458b53b732dbdcb72a80c76794881e6db21f3ed (patch)
tree1f2655f1479fc4a21dda0a1b5a33796e791b5b40 /share/lua/test/fib.lua
downloadlua-Debian-x86_64.tar.gz
[luadist-git] add lua-5.1.5-Debian-x86_64 [ci skip]5.1.5-Debian-x86_64Debian-x86_64
Diffstat (limited to 'share/lua/test/fib.lua')
-rw-r--r--share/lua/test/fib.lua40
1 files changed, 40 insertions, 0 deletions
diff --git a/share/lua/test/fib.lua b/share/lua/test/fib.lua
new file mode 100644
index 0000000..97a921b
--- /dev/null
+++ b/share/lua/test/fib.lua
@@ -0,0 +1,40 @@
+-- fibonacci function with cache
+
+-- very inefficient fibonacci function
+function fib(n)
+ N=N+1
+ if n<2 then
+ return n
+ else
+ return fib(n-1)+fib(n-2)
+ end
+end
+
+-- a general-purpose value cache
+function cache(f)
+ local c={}
+ return function (x)
+ local y=c[x]
+ if not y then
+ y=f(x)
+ c[x]=y
+ end
+ return y
+ end
+end
+
+-- run and time it
+function test(s,f)
+ N=0
+ local c=os.clock()
+ local v=f(n)
+ local t=os.clock()-c
+ print(s,n,v,t,N)
+end
+
+n=arg[1] or 24 -- for other values, do lua fib.lua XX
+n=tonumber(n)
+print("","n","value","time","evals")
+test("plain",fib)
+fib=cache(fib)
+test("cached",fib)