[R] possible overflow/underflow error causing NaN in .trval when invoking trmat with degree 4

[Nerd of Darkness]

Hello all,
I have two copies of the same data; I want to compare trend matrices for
degrees 3 and 4, so I name the copies "triplo" and "quatro".
> triploSurface<-surf.ls(3,triplo)
> triploMat<-trmat(triploSurface,-150.0000,150.0000,-150.0000,150.0000, 300)

[This produces the expected triploSurface and triploMat results and can
be graphed.]


> quatroSurface<-surf.ls(4,quatro)
> quatroMat<-trmat(quatroSurface, -150,150,-150,150, 300)
Error in .trval(object, x, y) :
  NA/NaN/Inf in foreign function call (arg 5)

[This produces an apparently correct quatroSurface result but does not
produce any quatroMat result, just an error message.]

I think this is an overflow or underflow - i.e. I think I'm demanding
too much precision from the numbers.

The tail of the quatroSurface looks like this:
0.0238192479364594, NaN, -0.785397268575074,
0.258979557395067, 0.416633191734089, 0.48818709354019, 0.303158973109538,
0.0976576257799269, 0.0203250815697912, -0.24213596942919,
-0.0892132957309183,
0.975147904903443, 0.176878824295857, 0.0452657395908427,
0.0635179944972253,
NaN, NaN), beta = c(NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN,
NaN, NaN, NaN, NaN, NaN, NaN), wz = c(NaN, NaN, NaN, NaN, NaN,
NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN), rx = c(-126.5463, 108.6537
), ry = c(-128.3801, 135.6199), call = quote(surf.ls(np = 4,
    x = quatro))), .Names = c("x", "y", "z", "np", "f", "r",
"beta", "wz", "rx", "ry", "call"), class = "trls")


The tail of the triploSurface looks similar, but all its values are
well-behaved without any NaN problems

 0.0351979976095227, -1.36626369439296, -0.280695994275675,
0.40206378062954, 0.0633634395824397, 0.00569741981675165,
-0.513420054181769
), beta = c(106.769396311982, -2.24615036637542, 0.156526774285082,
1.80159305847556, -3.09710659318204, -0.524195072882179, 2.70901190859632,
-1.02836821322134, 4.80130168312262, 2.37977833647081), wz =
c(-0.0728849622348235,
-0.186585406288444, 0.415603707564799, 0.233806471348331,
0.330715976834796,
-0.0613265591678669, -0.242396311982404, -1.18446693543041,
-0.0285404338742694,
1.01075743539955, -0.210496969514736, -0.0515734891310018,
0.0473874764761177
), rx = c(-126.5463, 108.6537), ry = c(-128.3801, 135.6199),
    call = quote(surf.ls(np = 3, x = triplo))), .Names = c("x",
"y", "z", "np", "f", "r", "beta", "wz", "rx", "ry", "call"), class = "trls")


There seem to be two obvious possibilities:

A - I could get a well-behaved result with degree 4 if only I could
manage to use the correct commands.

B - This data doesn't have the right characteristics to support a degree
4 trend and thus I should limit myself to degree 3.

Any comments are welcome. Thanks.