The `predict`

methods for the classes that inherit from the
virtual classes `bSpline`

and `polySpline`

are used to
evaluate the spline or its derivatives. The `plot`

method for a
spline object first evaluates `predict`

with the `x`

argument missing, then plots the resulting `xyVector`

with
`type = "l"`

.

```
# S3 method for bSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for nbSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for pbSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for npolySpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for ppolySpline
predict(object, x, nseg = 50, deriv = 0, …)
```

object

An object that inherits from the `bSpline`

or the
`polySpline`

class.

x

A numeric vector of `x`

values at which to evaluate the
spline. If this argument is missing a suitable set of `x`

values is generated as a sequence of `nseq`

segments spanning
the range of the knots.

nseg

A positive integer giving the number of segments in a set
of equally-spaced `x`

values spanning the range of the knots
in `object`

. This value is only used if `x`

is missing.

deriv

An integer between 0 and `splineOrder(object) - 1`

specifying the derivative to evaluate.

…

further arguments passed to or from other methods.

an `xyVector`

with components

the supplied or inferred numeric vector of `x`

values

the value of the spline (or its `deriv`

'th derivative)
at the `x`

vector

# NOT RUN { require(graphics); require(stats) ispl <- interpSpline( weight ~ height, women ) opar <- par(mfrow = c(2, 2), las = 1) plot(predict(ispl, nseg = 201), # plots over the range of the knots main = "Original data with interpolating spline", type = "l", xlab = "height", ylab = "weight") points(women$height, women$weight, col = 4) plot(predict(ispl, nseg = 201, deriv = 1), main = "First derivative of interpolating spline", type = "l", xlab = "height", ylab = "weight") plot(predict(ispl, nseg = 201, deriv = 2), main = "Second derivative of interpolating spline", type = "l", xlab = "height", ylab = "weight") plot(predict(ispl, nseg = 401, deriv = 3), main = "Third derivative of interpolating spline", type = "l", xlab = "height", ylab = "weight") par(opar) # }