dmat {bspline} R Documentation

## Differentiation matrix

### Description

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.

### Usage

dmat(nqw = NULL, xk = NULL, n = NULL, f = NULL, same_xk = FALSE)


### Arguments

 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 dbsp

### Value

Numeric matrix of size nqw-1 x nqw

[Package bspline version 2.1 Index]