-
numpy.polynomial.legendre.legvander(x, deg)
[source] -
Pseudo-Vandermonde matrix of given degree.
Returns the pseudo-Vandermonde matrix of degree
deg
and sample pointsx
. The pseudo-Vandermonde matrix is defined bywhere
0 <= i <= deg
. The leading indices ofV
index the elements ofx
and the last index is the degree of the Legendre polynomial.If
c
is a 1-D array of coefficients of lengthn + 1
andV
is the arrayV = legvander(x, n)
, thennp.dot(V, c)
andlegval(x, c)
are the same up to roundoff. This equivalence is useful both for least squares fitting and for the evaluation of a large number of Legendre series of the same degree and sample points.Parameters: x : array_like
Array of points. The dtype is converted to float64 or complex128 depending on whether any of the elements are complex. If
x
is scalar it is converted to a 1-D array.deg : int
Degree of the resulting matrix.
Returns: vander : ndarray
The pseudo-Vandermonde matrix. The shape of the returned matrix is
x.shape + (deg + 1,)
, where The last index is the degree of the corresponding Legendre polynomial. The dtype will be the same as the convertedx
.
numpy.polynomial.legendre.legvander()
2017-01-10 18:17:37
Please login to continue.