Add one Legendre series to another.
Returns the sum of two Legendre series c1 + c2. The arguments are sequences of coefficients ordered from lowest order term to highest, i.e., [1,2,3] represents the series
P_0 + 2*P_1 + 3*P_2.
c1, c2 : array_like
1-D arrays of Legendre series coefficients ordered from low to high.
out : ndarray
Array representing the Legendre series of their sum.
Unlike multiplication, division, etc., the sum of two Legendre series is a Legendre series (without having to “reproject” the result onto the basis set) so addition, just like that of “standard” polynomials, is simply “component-wise.”
>>> from numpy.polynomial import legendre as L >>> c1 = (1,2,3) >>> c2 = (3,2,1) >>> L.legadd(c1,c2) array([ 4., 4., 4.])