Returns a matrix with special attritutes that represents an orthonormal
polynomial.
USAGE:
poly.raw(x, degree=1, xname=<<see below>>, coefs)
REQUIRED ARGUMENTS:
x
a numeric vector.
OPTIONAL ARGUMENTS:
degree
a number, the degree of the orthonormal polynomial.
xname
optional character name suffix for the columns; if supplied, the columns
will be labelled
"xname^1",
"xname^2", etc,
otherwise simply
"1",
"2", etc.
coefs
list of normalization constants.
This is usually the
coefs attribute of an object created
by a previous call to
poly or
poly.raw.
If missing, the polynomials are self-normalized.
VALUE:
a matrix of orthonormal polynomials is returned.
The output of
poly.raw(x, degree) is identical to that of
poly(x, degree)
, and in fact
poly.raw is the workhorse for
poly. The
basis matrix has two attributes:
degree gives the degree for each
column, while
coefs contains the normalization constants used to
construct the orthonormal polynomials. These can be used in subsequent
calls to
poly.raw with different values for
x, in order to evaluate
the same polynomial basis functions at different abscissa values.
SEE ALSO:
,
,
,
,
.
EXAMPLES:
basis <- poly.raw(x, 5) # generate a basis for 5th degree polynomials
basis2 <- poly.raw( x2, 5, coefs = attr(basis,"coefs"))
# evaluate the same quintic basis functions at different values of x