zero, an Octave code which finds a zero of a scalar function of a scalar variable, by Richard Brent.
The method does not require the use of derivatives, and does not assume that the function is differentiable.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
zero is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and an Octave version and a Python version and an R version.
fsolve_test, an Octave code which calls fsolve() which seeks the solution x of one or more nonlinear equations f(x)=0.
test_zero, an Octave code which defines some test functions for which zeroes can be sought.
Original FORTRAN77 version by Richard Brent; Octave version by John Burkardt.