# interpret.logbin.smooth: Interpret a logbin.smooth Formula In logbin: Relative Risk Regression Using the Log-Binomial Model

## Description

This is an internal function of package `logbin`. It is a service routine for `logbin.smooth` which interprets the smooth parts of the model formula and returns modified formulas to be used in the fitting functions.

Not normally called directly.

## Usage

 `1` ```interpret.logbin.smooth(formula) ```

## Arguments

 `formula` A formula as supplied to `logbin.smooth`, which includes at least one `B` or `Iso` term.

## Value

A list with components:

 `full.formula` a `formula` object which is the same as the `formula` supplied, but with additional arguments removed from the smooth terms. E.g. `B(x, knot.range = 0:2)` would appear as `B(x)` in this formula. `fake.formula` a `formula` object which is the same as the `formula` supplied, but with smooth terms replaced by their covariates alone. E.g. `B(x, knot.range = 0:2)` would appear as `x` in this formula. Used to construct the model matrix. `smooth.spec` a named list containing the results of `eval`uating the smooth terms. See `B` and `Iso` for details. `smooth.ind` a vector containing the indices of the smooth components in the `formula`. `terms` the result of running `terms.formula(formula, specials = c("B", "Iso"))`.

## Author(s)

Mark W. Donoghoe markdonoghoe@gmail.com

`logbin.smooth`
 ```1 2 3 4 5 6``` ```# Specify a smooth model with knot.range res <- interpret.logbin.smooth(y ~ B(x, knot.range = 0:2) + x2) # The knot.range is removed from the full.formula... print(res\$full.formula) # ...but is stored in the \$smooth.spec component of the result: print(res\$smooth.spec\$x\$knot.range) ```