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authorNguyễn Gia Phong <vn.mcsinyx@gmail.com>2020-02-16 14:26:55 +0700
committerNguyễn Gia Phong <vn.mcsinyx@gmail.com>2020-02-16 14:26:55 +0700
commit82e6cf7d1046d6cee16f7e8b044ec33e7ec6c4b7 (patch)
treef7b7ae0bce69070c47a1b31a85bd2bc69dfecf09 /usth/MATH2.4/labwork/1/ratpoison.m
parent29d1001e2e21eff289bff23412e284c8b2e44595 (diff)
downloadcp-82e6cf7d1046d6cee16f7e8b044ec33e7ec6c4b7.tar.gz
[usth] Numerical Method is MATH2.4
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+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