scipy.interpolate.CubicSpline.solve¶

CubicSpline.
solve
(y=0.0, discontinuity=True, extrapolate=None)[source]¶ Find real solutions of the the equation
pp(x) == y
.Parameters: y : float, optional
Righthand side. Default is zero.
discontinuity : bool, optional
Whether to report sign changes across discontinuities at breakpoints as roots.
extrapolate : {bool, ‘periodic’, None}, optional
If bool, determines whether to return roots from the polynomial extrapolated based on first and last intervals, ‘periodic’ works the same as False. If None (default), use self.extrapolate.
Returns: roots : ndarray
Roots of the polynomial(s).
If the PPoly object describes multiple polynomials, the return value is an object array whose each element is an ndarray containing the roots.
Notes
This routine works only on realvalued polynomials.
If the piecewise polynomial contains sections that are identically zero, the root list will contain the start point of the corresponding interval, followed by a
nan
value.If the polynomial is discontinuous across a breakpoint, and there is a sign change across the breakpoint, this is reported if the discont parameter is True.
Examples
Finding roots of
[x**2  1, (x  1)**2]
defined on intervals[2, 1], [1, 2]
:>>> from scipy.interpolate import PPoly >>> pp = PPoly(np.array([[1, 4, 3], [1, 0, 0]]).T, [2, 1, 2]) >>> pp.roots() array([1., 1.])