From f065d7884d353c3545535850e4e8bdf8e10025ca Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Thu, 6 Dec 2018 00:32:34 +0800
Subject: =?UTF-8?q?*=E5=88=9D=E5=A7=8B=E5=8C=96?=
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---
 libs/lua-5.1.5/test/bisect.lua | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 libs/lua-5.1.5/test/bisect.lua

(limited to 'libs/lua-5.1.5/test/bisect.lua')

diff --git a/libs/lua-5.1.5/test/bisect.lua b/libs/lua-5.1.5/test/bisect.lua
new file mode 100644
index 0000000..f91e69b
--- /dev/null
+++ b/libs/lua-5.1.5/test/bisect.lua
@@ -0,0 +1,27 @@
+-- bisection method for solving non-linear equations
+
+delta=1e-6	-- tolerance
+
+function bisect(f,a,b,fa,fb)
+ local c=(a+b)/2
+ io.write(n," c=",c," a=",a," b=",b,"\n")
+ if c==a or c==b or math.abs(a-b)<delta then return c,b-a end
+ n=n+1
+ local fc=f(c)
+ if fa*fc<0 then return bisect(f,a,c,fa,fc) else return bisect(f,c,b,fc,fb) end
+end
+
+-- find root of f in the inverval [a,b]. needs f(a)*f(b)<0
+function solve(f,a,b)
+ n=0
+ local z,e=bisect(f,a,b,f(a),f(b))
+ io.write(string.format("after %d steps, root is %.17g with error %.1e, f=%.1e\n",n,z,e,f(z)))
+end
+
+-- our function
+function f(x)
+ return x*x*x-x-1
+end
+
+-- find zero in [1,2]
+solve(f,1,2)
-- 
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