bisect#
- scipy.optimize.bisect(f, a, b, args=(), xtol=2e-12, rtol=8.881784197001252e-16, maxiter=100, full_output=False, disp=True)[source]#
- Find root of a function within an interval using bisection. - Basic bisection routine to find a root of the function f between the arguments a and b. f(a) and f(b) cannot have the same signs. Slow but sure. - Parameters:
- ffunction
- Python function returning a number. f must be continuous, and f(a) and f(b) must have opposite signs. 
- ascalar
- One end of the bracketing interval [a,b]. 
- bscalar
- The other end of the bracketing interval [a,b]. 
- xtolnumber, optional
- The computed root - x0will satisfy- np.allclose(x, x0, atol=xtol, rtol=rtol), where- xis the exact root. The parameter must be positive.
- rtolnumber, optional
- The computed root - x0will satisfy- np.allclose(x, x0, atol=xtol, rtol=rtol), where- xis the exact root. The parameter cannot be smaller than its default value of- 4*np.finfo(float).eps.
- maxiterint, optional
- If convergence is not achieved in maxiter iterations, an error is raised. Must be >= 0. 
- argstuple, optional
- Containing extra arguments for the function f. f is called by - apply(f, (x)+args).
- full_outputbool, optional
- If full_output is False, the root is returned. If full_output is True, the return value is - (x, r), where x is the root, and r is a- RootResultsobject.
- dispbool, optional
- If True, raise RuntimeError if the algorithm didn’t converge. Otherwise, the convergence status is recorded in a - RootResultsreturn object.
 
- Returns:
- rootfloat
- Root of f between a and b. 
- rRootResults(present iffull_output = True)
- Object containing information about the convergence. In particular, - r.convergedis True if the routine converged.
 
 - See also - Examples - >>> def f(x): ... return (x**2 - 1) - >>> from scipy import optimize - >>> root = optimize.bisect(f, 0, 2) >>> root 1.0 - >>> root = optimize.bisect(f, -2, 0) >>> root -1.0