gek (version 1.2.0)

derivModelMatrix: Derivatives of Model Matrix

Description

Determine the derivatives of a model matrix.

Usage

derivModelMatrix(object, ...)
# S3 method for default
derivModelMatrix(object, data, ...)
# S3 method for gekm
derivModelMatrix(object, ...)
# S3 method for gekm
model.matrix(object, ...)

Value

The derivatives of the model (or design) matrix.

As in model.matrix there is an attribute "assign".

Arguments

object

an object of an appropriate class. For the default method, a formula defining the regression functions.

data

a data.frame with named columns.

...

further arguments, yet not used.

Author

Carmen van Meegen

Details

derivModelMatrix makes use of the function deriv. Accordingly, the calculation of derivatives is only possible for functions that are contained in the derivatives table of deriv.

Note, in contrast to model.matrix, factors are not supported.

See Also

deriv for more details on supported arithmetic operators and functions.

model.matrix for construction of a design (or model) matrix.

Examples

## Several examples for the derivatives of a model matrix

dat <- data.frame(x1 = seq(-2, 2, length.out = 5))

model.matrix(~ 1, dat)
derivModelMatrix(~ 1, dat)

model.matrix(~ ., dat)
derivModelMatrix(~ ., dat)

model.matrix(~ . - 1, dat)
derivModelMatrix(~ . - 1, dat)

model.matrix(~ sin(x1) + I(x1^2), dat)
derivModelMatrix(~ sin(x1) + I(x1^2), dat)

dat <- cbind(dat, x2 = seq(1, 5, length.out = 5))

model.matrix(~ 1, dat)
derivModelMatrix(~ 1, dat)

model.matrix(~ .^2, dat)
derivModelMatrix(~ .^2, dat)

model.matrix(~ log(x2), dat)
derivModelMatrix(~ log(x2), dat)

model.matrix(~ x1:x2, dat)
derivModelMatrix(~ x1:x2, dat)

model.matrix(~ I(x1^2) * I(x2^3), dat)
derivModelMatrix(~ I(x1^2) * I(x2^3), dat)

model.matrix(~ sin(x1) + cos(x2) + atan(x1 * x2), dat)
derivModelMatrix(~ sin(x1) + cos(x2) + atan(x1 * x2), dat)