niters: Number of Iterations

In VGAM: Vector Generalized Linear and Additive Models

Number of Iterations

Description

Extracts the number of IRLS iterations performed for a VGLM object.

Usage

niters(object, ...)
niters.vlm(object, history = FALSE, ...)

Arguments

object	A vglm object. Currently a vgam object is accepted but the correct value is not returned.
history	Logical, if TRUE it returns the convergence history with respect to the criterion, e.g., vglm.control()[["criterion"]].
...	Currently unused.

Details

The number of iteratively reweighted least squares (IRLS) iterations needed for convergence (or non-convergence) does say something about the model. Since Fisher scoring has a linear convergence rate in general, it should take no more than 10 iterations, say, for successful convergence. Much more indicates potential problems, e.g., a large disagreement between data and the specified model.

Value

A non-negative integer by default. If history = TRUE then a matrix.

Note

Step-halving may or may not affect the answer.

See Also

vglm, vglm.control.

Examples

fit <- vglm(rpois(9, 2) ~ 1, poissonff, crit = "c")
niters(fit)
niters(fit, history = TRUE)

VGAM documentation built on Dec. 4, 2025, 1:07 a.m.