Creating B-spline basis functions from an extended knot sequence

[wenjie2wang]

Hi @BerriJ

It seems that the package profoc needs constructing B-splines with an extended knot sequence. You used the package splines2 that I maintained for this task. However, the constructor you are using is not intended for the extended knot sequences. The future version of package splines2 will check the placement of the internal knots more strictly to resolve wenjie2wang/splines2#5. As a result, the testing examples in tests/testthat/test-spline-basis.R will fail.

To resolve this issue, I would suggest using the constructor intended for the extended knot sequences. For example,

Rcpp::sourceCpp(code = "
#include <RcppArmadillo.h>
#include <splines2Armadillo.h>
// [[Rcpp::depends(RcppArmadillo)]]
// [[Rcpp::depends(splines2)]]
using namespace splines2;
using namespace arma;
// [[Rcpp::export]]
mat splines2_basis(const vec &x,
                   const vec &knots,
                   const unsigned int deg)
{
    splines2::BSpline bs_obj{x, deg, knots};
    return bs_obj.basis(true);
}")

order <- 4
deg <- order - 1
pstep <- 0.01
x <- seq(pstep, 1 - pstep, pstep)
knots <- seq.int(- 0.2, 1.2, 0.1)
res0 <- splines::splineDesign(knots, x, order, outer.ok = TRUE)
res1 <- splines2_basis(x, knots, deg)
all.equal(res0, res1)
#> [1] TRUE

^{Created on 2021-08-08 by the reprex package (v2.0.0)}

[BerriJ]

Hi @wenjie2wang,

I just added some commits onto your PR and merged it. Btw thank you very much. I keep the main branch strictly corresponding to the latest CRAN release. Therefore, I merged into develop.

Do you already know when your changes are hitting CRAN?

Best
Jonathan

[wenjie2wang]

Thanks for your quick actions!

Do you already know when your changes are hitting CRAN?

I intended to submit a new version of splines2 in two weeks. Thus, I would appreciate it if you could submit the updated version of profoc to CRAN in one or two weeks.

[BerriJ]

I expect that I'm able to submit it to CRAN early next week (~16.08.2021). I hope this suits you well.

By the way: thanks a lot for your great package. It resolved a lot of hassle. :)

[wenjie2wang]

That would be great. Thanks!

[BerriJ]

V 0.8.3 which resolves this issue was released on CRAN today.