Predict.matrix {mgcv} | R Documentation |

## Prediction methods for smooth terms in a GAM

### Description

Takes `smooth`

objects produced by `smooth.construct`

methods and obtains the matrix mapping
the parameters associated with such a smooth to the predicted values of the smooth at a set of new covariate values.

In practice this method is often called via the wrapper function `PredictMat`

.

### Usage

Predict.matrix(object,data)

### Arguments

`object` |
is a smooth object produced by a `smooth.construct` method function. The object
contains all the information required to specify the basis for a term of its class, and this information is
used by the appropriate `Predict.matrix` function to produce a prediction matrix for new covariate values.
Further details are given in `smooth.construct` . |

`data` |
A data frame containing the values of the (named) covariates at which the smooth term is to be
evaluated. |

### Details

Smooth terms in a GAM formula are turned into smooth specification objects of
class `xx.smooth.spec`

during processing of the formula. Each of these objects is
converted to a smooth object using an appropriate `smooth.construct`

function. The `Predict.matrix`

functions are used to obtain the matrix that will map the parameters associated with a smooth term to
the predicted values for the term at new covariate values.

Note that new smooth classes can be added by writing a new `smooth.construct`

method function and a
corresponding `Predict.matrix`

method function: see the example code provided for
`smooth.construct`

for details.

### Value

A matrix which will map the parameters associated with the smooth to the vector of values of the smooth
evaluated at the covariate values given in `object`

.

### Author(s)

Simon N. Wood simon.wood@r-project.org

### References

Wood, S.N. (2000) Modelling and Smoothing Parameter Estimation
with Multiple Quadratic Penalties. J.R.Statist.Soc.B 62(2):413-428

Wood, S.N. (2003) Thin plate regression splines. J.R.Statist.Soc.B 65(1):95-114

Wood, S.N. (in press) Stable and efficient multiple smoothing parameter estimation for
generalized additive models. J. Amer. Statist. Ass.

http://www.stats.gla.ac.uk/~simon/

### See Also

`gam`

,`gamm`

,
`smooth.construct`

, `PredictMat`

### Examples

# See smooth.construct examples

[Package

*mgcv* version 1.2-3

Index]