dmat {bspline} | R Documentation |
Calculate matrix for obtaining coefficients of first-derivative B-spline.
They can be calculated as dqw=Md %*% qw
. Here, dqw are coefficients
of the first derivative,
Md is the matrix returned by this function, and qw are the coefficients
of differentiated B-spline.
dmat(nqw = NULL, xk = NULL, n = NULL, f = NULL, same_xk = FALSE)
nqw |
Integer scalar, row number of qw matrix (i.e. degree of freedom of a B-spline) |
xk |
Numeric vector, knot positions |
n |
Integer scalar, B-spline polynomial order |
f |
Function from which previous parameters can be retrieved. If both f and any of previous parameters are given then explicitly set parameters take precedence over those retrieved from f. |
same_xk |
Logical scalar, the same meaning as in |
Numeric matrix of size nqw-1 x nqw