This is a matlab code according to a modified Brent's method for finding zeros of functions by Gautam Wilkins and Ming Gu, which is published in Numerische Mathematik: 26 June 2012 (Mathematics Subject Classification (2000) 65Y20·65Y04).
When root_tol = 1e-12, func_tol = 1e-14, the number of function evaluations is almost the same as that in the thesis.