numpy.polynomial.laguerre.lagint(c, m=1, k=, lbnd=0, scl=1, axis=0)
Integrate a Laguerre series.
Returns the Laguerre series coefficients
m times from
axis. At each iteration the resulting series is multiplied by
scl and an integration constant,
k, is added. The scaling factor is for use in a linear change of variable. (“Buyer beware”: note that, depending on what one is doing, one may want
scl to be the reciprocal of what one might expect; for more information, see the Notes section below.) The argument
c is an array of coefficients from low to high degree along each axis, e.g., [1,2,3] represents the series
L_0 + 2*L_1 + 3*L_2 while [[1,2],[1,2]] represents
1*L_0(x)*L_0(y) + 1*L_1(x)*L_0(y) + 2*L_0(x)*L_1(y) +
2*L_1(x)*L_1(y) if axis=0 is
x and axis=1 is
Note that the result of each integration is multiplied by
scl. Why is this important to note? Say one is making a linear change of variable in an integral relative to
x. Then , so one will need to set
scl equal to - perhaps not what one would have first thought.
Also note that, in general, the result of integrating a C-series needs to be “reprojected” onto the C-series basis set. Thus, typically, the result of this function is “unintuitive,” albeit correct; see Examples section below.
>>> from numpy.polynomial.laguerre import lagint >>> lagint([1,2,3]) array([ 1., 1., 1., -3.]) >>> lagint([1,2,3], m=2) array([ 1., 0., 0., -4., 3.]) >>> lagint([1,2,3], k=1) array([ 2., 1., 1., -3.]) >>> lagint([1,2,3], lbnd=-1) array([11.5, 1. , 1. , -3. ]) >>> lagint([1,2], m=2, k=[1,2], lbnd=-1) array([ 11.16666667, -5. , -3. , 2. ]) # may vary
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