On Fri, Jun 29, 2012 at 6:18 AM, Silkworth,David J. <silkw...@airproducts.com> wrote: > With respect to replies: > > a) fit a decent, modern, documented C++ implementation of what is needed > > Yes, this was the question. Can anyone help? I am failing right here. > >> and of course if a) fails, one can always 'rip out' what is underneath a >> known R function and use that as a fallback. > > This is where I am. I can easily (I think) 'rip out' kind Douglas Bate's two > C functions: > > /* Exports */ > SEXP spline_basis(SEXP knots, SEXP order, SEXP xvals, SEXP derivs); > SEXP spline_value(SEXP knots, SEXP coeff, SEXP order, SEXP x, SEXP deriv); > > By initially just placing the entire contents of splines.c in the inline > header for testing. > > The challenge now is to send one or both of these the correct arguments, and > somehow come up with an order (3 for the cubic spline) by length(xvals) > matrix from what appears to be individual vectors returning from calls here. > > Since the entire topic of the boor algorithm is new to me just this week this > remains a daunting challenge. I plan to single step through the R code of > ns() and splineDesign(), which it calls, just to see what args are what and > what return objects are what.
His name is "de Boor", as in http://en.wikipedia.org/wiki/Carl_R._de_Boor > We just can't stand for code in the middle of a double loop to go to R just > to get all the "boiler-plate" of the R code in ns(). We need to know how to > call spline_basis directly with confidence. > > I'm just looking to get one function to work for one problem. No thought at > this time of actually attempting something like building an "Rf_ns" function > to bind into Rcpp. > > I suppose if one were to go that far, after understanding what I must, > Davor's black art method might be interesting. But that is a long way off > from where I stand today. We can rip code into one thesis project and be > done I hope. > > > > > _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
