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- """
- A sub-package for efficiently dealing with polynomials.
- Within the documentation for this sub-package, a "finite power series,"
- i.e., a polynomial (also referred to simply as a "series") is represented
- by a 1-D numpy array of the polynomial's coefficients, ordered from lowest
- order term to highest. For example, array([1,2,3]) represents
- ``P_0 + 2*P_1 + 3*P_2``, where P_n is the n-th order basis polynomial
- applicable to the specific module in question, e.g., `polynomial` (which
- "wraps" the "standard" basis) or `chebyshev`. For optimal performance,
- all operations on polynomials, including evaluation at an argument, are
- implemented as operations on the coefficients. Additional (module-specific)
- information can be found in the docstring for the module of interest.
- This package provides *convenience classes* for each of six different kinds
- of polynomials:
- ======================== ================
- **Name** **Provides**
- ======================== ================
- `~polynomial.Polynomial` Power series
- `~chebyshev.Chebyshev` Chebyshev series
- `~legendre.Legendre` Legendre series
- `~laguerre.Laguerre` Laguerre series
- `~hermite.Hermite` Hermite series
- `~hermite_e.HermiteE` HermiteE series
- ======================== ================
- These *convenience classes* provide a consistent interface for creating,
- manipulating, and fitting data with polynomials of different bases.
- The convenience classes are the preferred interface for the `~numpy.polynomial`
- package, and are available from the ``numpy.polynomial`` namespace.
- This eliminates the need to navigate to the corresponding submodules, e.g.
- ``np.polynomial.Polynomial`` or ``np.polynomial.Chebyshev`` instead of
- ``np.polynomial.polynomial.Polynomial`` or
- ``np.polynomial.chebyshev.Chebyshev``, respectively.
- The classes provide a more consistent and concise interface than the
- type-specific functions defined in the submodules for each type of polynomial.
- For example, to fit a Chebyshev polynomial with degree ``1`` to data given
- by arrays ``xdata`` and ``ydata``, the
- `~chebyshev.Chebyshev.fit` class method::
- >>> from numpy.polynomial import Chebyshev
- >>> c = Chebyshev.fit(xdata, ydata, deg=1)
- is preferred over the `chebyshev.chebfit` function from the
- ``np.polynomial.chebyshev`` module::
- >>> from numpy.polynomial.chebyshev import chebfit
- >>> c = chebfit(xdata, ydata, deg=1)
- See :doc:`routines.polynomials.classes` for more details.
- Convenience Classes
- ===================
- The following lists the various constants and methods common to all of
- the classes representing the various kinds of polynomials. In the following,
- the term ``Poly`` represents any one of the convenience classes (e.g.
- `~polynomial.Polynomial`, `~chebyshev.Chebyshev`, `~hermite.Hermite`, etc.)
- while the lowercase ``p`` represents an **instance** of a polynomial class.
- Constants
- ---------
- - ``Poly.domain`` -- Default domain
- - ``Poly.window`` -- Default window
- - ``Poly.basis_name`` -- String used to represent the basis
- - ``Poly.maxpower`` -- Maximum value ``n`` such that ``p**n`` is allowed
- - ``Poly.nickname`` -- String used in printing
- Creation
- --------
- Methods for creating polynomial instances.
- - ``Poly.basis(degree)`` -- Basis polynomial of given degree
- - ``Poly.identity()`` -- ``p`` where ``p(x) = x`` for all ``x``
- - ``Poly.fit(x, y, deg)`` -- ``p`` of degree ``deg`` with coefficients
- determined by the least-squares fit to the data ``x``, ``y``
- - ``Poly.fromroots(roots)`` -- ``p`` with specified roots
- - ``p.copy()`` -- Create a copy of ``p``
- Conversion
- ----------
- Methods for converting a polynomial instance of one kind to another.
- - ``p.cast(Poly)`` -- Convert ``p`` to instance of kind ``Poly``
- - ``p.convert(Poly)`` -- Convert ``p`` to instance of kind ``Poly`` or map
- between ``domain`` and ``window``
- Calculus
- --------
- - ``p.deriv()`` -- Take the derivative of ``p``
- - ``p.integ()`` -- Integrate ``p``
- Validation
- ----------
- - ``Poly.has_samecoef(p1, p2)`` -- Check if coefficients match
- - ``Poly.has_samedomain(p1, p2)`` -- Check if domains match
- - ``Poly.has_sametype(p1, p2)`` -- Check if types match
- - ``Poly.has_samewindow(p1, p2)`` -- Check if windows match
- Misc
- ----
- - ``p.linspace()`` -- Return ``x, p(x)`` at equally-spaced points in ``domain``
- - ``p.mapparms()`` -- Return the parameters for the linear mapping between
- ``domain`` and ``window``.
- - ``p.roots()`` -- Return the roots of `p`.
- - ``p.trim()`` -- Remove trailing coefficients.
- - ``p.cutdeg(degree)`` -- Truncate p to given degree
- - ``p.truncate(size)`` -- Truncate p to given size
- """
- from .polynomial import Polynomial
- from .chebyshev import Chebyshev
- from .legendre import Legendre
- from .hermite import Hermite
- from .hermite_e import HermiteE
- from .laguerre import Laguerre
- __all__ = [
- "set_default_printstyle",
- "polynomial", "Polynomial",
- "chebyshev", "Chebyshev",
- "legendre", "Legendre",
- "hermite", "Hermite",
- "hermite_e", "HermiteE",
- "laguerre", "Laguerre",
- ]
- def set_default_printstyle(style):
- """
- Set the default format for the string representation of polynomials.
- Values for ``style`` must be valid inputs to ``__format__``, i.e. 'ascii'
- or 'unicode'.
- Parameters
- ----------
- style : str
- Format string for default printing style. Must be either 'ascii' or
- 'unicode'.
- Notes
- -----
- The default format depends on the platform: 'unicode' is used on
- Unix-based systems and 'ascii' on Windows. This determination is based on
- default font support for the unicode superscript and subscript ranges.
- Examples
- --------
- >>> p = np.polynomial.Polynomial([1, 2, 3])
- >>> c = np.polynomial.Chebyshev([1, 2, 3])
- >>> np.polynomial.set_default_printstyle('unicode')
- >>> print(p)
- 1.0 + 2.0·x + 3.0·x²
- >>> print(c)
- 1.0 + 2.0·T₁(x) + 3.0·T₂(x)
- >>> np.polynomial.set_default_printstyle('ascii')
- >>> print(p)
- 1.0 + 2.0 x + 3.0 x**2
- >>> print(c)
- 1.0 + 2.0 T_1(x) + 3.0 T_2(x)
- >>> # Formatting supersedes all class/package-level defaults
- >>> print(f"{p:unicode}")
- 1.0 + 2.0·x + 3.0·x²
- """
- if style not in ('unicode', 'ascii'):
- raise ValueError(
- f"Unsupported format string '{style}'. Valid options are 'ascii' "
- f"and 'unicode'"
- )
- _use_unicode = True
- if style == 'ascii':
- _use_unicode = False
- from ._polybase import ABCPolyBase
- ABCPolyBase._use_unicode = _use_unicode
- from numpy._pytesttester import PytestTester
- test = PytestTester(__name__)
- del PytestTester
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