numpy.polynomial.legendre.legsub

numpy.polynomial.legendre.legsub(c1, c2)

Subtract one Legendre series from another.

Returns the difference of two Legendre series c1 - c2. The sequences of coefficients are from lowest order term to highest, i.e., [1,2,3] represents the series P_0 + 2*P_1 + 3*P_2.

Parameters

c1, c2array_like

1-D arrays of Legendre series coefficients ordered from low to high.

Returns

outndarray

Of Legendre series coefficients representing their difference.

See also

legadd, legmulx, legmul, legdiv, legpow

Notes

Unlike multiplication, division, etc., the difference of two Legendre series is a Legendre series (without having to “reproject” the result onto the basis set) so subtraction, just like that of “standard” polynomials, is simply “component-wise.”

Examples

>>> from numpy.polynomial import legendre as L
>>> c1 = (1,2,3)
>>> c2 = (3,2,1)
>>> L.legsub(c1,c2)
array([-2.,  0.,  2.])
>>> L.legsub(c2,c1) # -C.legsub(c1,c2)
array([ 2.,  0., -2.])