scipy.interpolate.PPoly¶

class
scipy.interpolate.
PPoly
(c, x, extrapolate=None, axis=0)[source]¶ Piecewise polynomial in terms of coefficients and breakpoints
The polynomial between
x[i]
andx[i + 1]
is written in the local power basis:S = sum(c[m, i] * (xp  x[i])**(km) for m in range(k+1))
where
k
is the degree of the polynomial. Parameters
 cndarray, shape (k, m, …)
Polynomial coefficients, order k and m intervals
 xndarray, shape (m+1,)
Polynomial breakpoints. Must be sorted in either increasing or decreasing order.
 extrapolatebool or ‘periodic’, optional
If bool, determines whether to extrapolate to outofbounds points based on first and last intervals, or to return NaNs. If ‘periodic’, periodic extrapolation is used. Default is True.
 axisint, optional
Interpolation axis. Default is zero.
See also
BPoly
piecewise polynomials in the Bernstein basis
Notes
Highorder polynomials in the power basis can be numerically unstable. Precision problems can start to appear for orders larger than 2030.
 Attributes
 xndarray
Breakpoints.
 cndarray
Coefficients of the polynomials. They are reshaped to a 3dimensional array with the last dimension representing the trailing dimensions of the original coefficient array.
 axisint
Interpolation axis.
Methods
__call__
(x[, nu, extrapolate])Evaluate the piecewise polynomial or its derivative.
derivative
([nu])Construct a new piecewise polynomial representing the derivative.
antiderivative
([nu])Construct a new piecewise polynomial representing the antiderivative.
integrate
(a, b[, extrapolate])Compute a definite integral over a piecewise polynomial.
solve
([y, discontinuity, extrapolate])Find real solutions of the the equation
pp(x) == y
.roots
([discontinuity, extrapolate])Find real roots of the the piecewise polynomial.
extend
(c, x[, right])Add additional breakpoints and coefficients to the polynomial.
from_spline
(tck[, extrapolate])Construct a piecewise polynomial from a spline
from_bernstein_basis
(bp[, extrapolate])Construct a piecewise polynomial in the power basis from a polynomial in Bernstein basis.
construct_fast
(c, x[, extrapolate, axis])Construct the piecewise polynomial without making checks.