[R-pkg-devel] Errors in my package

To Whom It May Concern:

     I have created a package called "freeknotsplines" in R, and I need to
make a few updates to it.  I resubmitted the package, and received the
following error message:

checking examples ... ERROR
Running examples in ?freeknotsplines-Ex.R? failed
The error most likely occurred in:

base::assign(".ptime", proc.time(), pos = "CheckExEnv")
### Name: coef.freekt
### Title: Compute Coefficients of B-Splines For Free-Knot Splines
### Aliases: coef.freekt
### Keywords: nonparametric regression smooth

### ** Examples

x <- 0:30/30
truey <- x*sin(10*x)
set.seed(10556)
y <- truey + rnorm(31, 0, 0.2)
xy.freekt <- freelsgen(x, y, degree = 2, numknot = 2, 555)
coef(xy.freekt)

Error: $ operator not defined for this S4 class
Execution halted

      This error occurs in one of the examples in the documentation.   It is
platform dependent, and does not occur on the machine I am using to create
the package.  freekt is a new class, which is intended to be a S3 class,
not a S4 class.

  Here is the code for coef.freekt:

coef.freekt <- function(object, ...)
{
   xdat <- object at x
   ydat <- object at y

   optknot <- object at optknot
   ord <- object at degree + 1
   lambda <- object at lambda
   fulloptknot <- c(rep(min(xdat), ord), optknot, rep(max(xdat), ord))  #
includes endpoints
   Xmat <- splineDesign(fulloptknot, xdat, ord)
   if ((lambda == 0) | (length(optknot) == 0))
     coef <- solve(t(Xmat)%*%Xmat, t(Xmat)%*%ydat)
   else
     {
       numknots <- length(optknot)
       Amat <- chgbasismat(fulloptknot, ord)
       Istar <- diag(c(rep(0, times = ord), rep(1, times = numknots)))
       coef <- solve(t(Xmat)%*%Xmat + lambda*t(Amat)%*%Istar%*%Amat,
                     t(Xmat)%*%ydat)
     }
   return(coef)
}

Can someone please help me figure out what I am doing that is causing this
error?

Sincerely,

Steven Spiriti

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