MortSmooth_bbase {ungroup} | R Documentation |
Construct B-spline basis
Description
This is an internal function of package MortalitySmooth which creates equally-spaced B-splines basis over an abscissa of data.
Usage
MortSmooth_bbase(x, xl, xr, ndx, deg)
Arguments
x |
vector for the abscissa of data; |
xl |
left boundary; |
xr |
right boundary; |
ndx |
number of internal knots minus one or number of internal intervals; |
deg |
degree of the splines. |
Details
The function reproduce an algorithm presented by Eilers and Marx (2010) using differences of truncated power functions (see MortSmooth_tpower). The final matrix has a single B-spline for each of the [ndx + deg] columns. The number of rows is equal to the length of x.
The function differs from bs in the package splines since it automatically constructed B-splines with identical shape. This would allow a simple interpretation of coefficients and application of simple differencing.
Value
A matrix containing equally-spaced B-splines of degree deg along x for each column.
Author(s)
Carlo G Camarda