From e461df7573c2b7b7e26c965d8cf2d8e175d67378 Mon Sep 17 00:00:00 2001 From: Nguyễn Gia Phong Date: Mon, 16 Dec 2019 21:31:18 +0700 Subject: [usth/MATH2.2] Numerical Methods The future starts now. --- usth/MATH2.2/labwork/1/ratpoison.m | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 usth/MATH2.2/labwork/1/ratpoison.m (limited to 'usth/MATH2.2/labwork/1/ratpoison.m') diff --git a/usth/MATH2.2/labwork/1/ratpoison.m b/usth/MATH2.2/labwork/1/ratpoison.m new file mode 100644 index 0000000..f2db823 --- /dev/null +++ b/usth/MATH2.2/labwork/1/ratpoison.m @@ -0,0 +1,15 @@ +function [x fx ea i] = ratpoison (f, df, x0, es = 0.00000001, imax = 20) + nargin < 2 && error ('ratpoison requires at least 2 ingredients'); + [x fx dfx ea i] = deal (x0, f (x0), df (x0), 1, 0); + while (ea > es && i++ < imax) + [xold x] = deal (x, x - fx/dfx); + [fx dfx] = deal (f (x), df (x)); + if (fx == 0) + ea = 0; + break; + elseif (x) + % just drop the percent BS + ea = abs ((x - xold) / x); + end + end +end -- cgit 1.4.1