1 files changed, 45 insertions, 0 deletions
diff --git a/Functions/falsePosition/falsePosition.m b/Functions/falsePosition/falsePosition.m
new file mode 100644
index 0000000..d2cb776
--- /dev/null
+++ b/Functions/falsePosition/falsePosition.m
@@ -0,0 +1,45 @@
+function [root, fx, ea, iter] = falsePosition(func, xl, xu, es, maxit, varargin)
+%falsePosition finds the root of a function using false position method
+%   Syntax:
+%	[root, fx, ea, iter] = falsePosition(func, xl, xu, es, maxit, varargin)
+%
+%   Input:
+%	func = function being evaluated
+%	xl = lower guess
+%	xu = upper guess
+%	es = desired relative error (default 0.0001%)
+%	maxit = maximum number of iterations (default 200)
+%	varargin, ...= any additional parameters used by the function
+%   Output:
+%	root = estimated root location
+%	fx = function evaluated at root location
+%	ea = approximated relative error (%)
+%	iter = number of iterations performed
+
+if nargin < 3, error('Too few arguments: at least 3 needed'), end
+if nargin < 4 | isempty(es), es = 0.0001; end
+if nargin < 5 | isempty(maxit), maxit = 200; end
+
+iter=0;
+ea=100;
+xr= xl;
+
+while(1)
+	xrold= xr;
+	iter = iter + 1;
+	xr=xu-func(xu)*(xl-xu)/(func(xl)-func(xu));
+	if xr~=0
+		ea = abs((xr-xrold)/xr)*100;
+	end
+	if func(xl)*func(xr)<0
+		xl=xr;
+	else
+		xl=xr;
+	end
+	if iter == maxit | ea <= es, break, end
+end
+root = xr;
+fx=func(xr,varargin{:});
+ea=ea;
+iter=iter;
+end
+\ No newline at end of file