diff options
author | chai <chaifix@163.com> | 2018-12-07 01:18:45 +0800 |
---|---|---|
committer | chai <chaifix@163.com> | 2018-12-07 01:18:45 +0800 |
commit | afc5ebdeece428d4ef72f4f1f4b178a92d1b9cba (patch) | |
tree | 664aff4bdf9841346f044cb2a2f3cb4b55eba386 /src/3rdparty/lua-5.1.5/test/bisect.lua | |
parent | 1acc1ecf398bc43bc304a449643fddbb65d1e733 (diff) |
+lua51
Diffstat (limited to 'src/3rdparty/lua-5.1.5/test/bisect.lua')
-rw-r--r-- | src/3rdparty/lua-5.1.5/test/bisect.lua | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/3rdparty/lua-5.1.5/test/bisect.lua b/src/3rdparty/lua-5.1.5/test/bisect.lua new file mode 100644 index 0000000..f91e69b --- /dev/null +++ b/src/3rdparty/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) |