solveGmm-methods: ~~ Methods for Function 'solveGmm' in Package 'momentfit' ~~

In momentfit: Methods of Moments

~~ Methods for Function solveGmm in Package momentfit ~~

Description

The main function to get the GMM solution for a given weighting matrix.

Usage

## S4 method for signature 'linearModel,momentWeights'
solveGmm(object, wObj, theta0=NULL,
...)

## S4 method for signature 'allNLModel,momentWeights'
solveGmm(object, wObj, theta0=NULL,
 algo=algoObj("optim"), ...)

## S4 method for signature 'rnonlinearModel,momentWeights'
solveGmm(object, wObj, theta0=NULL,
...)

## S4 method for signature 'slinearModel,sysMomentWeights'
solveGmm(object, wObj,
theta0=NULL, ...)

## S4 method for signature 'rslinearModel,sysMomentWeights'
solveGmm(object, wObj,
theta0=NULL, ...)

## S4 method for signature 'snonlinearModel,sysMomentWeights'
solveGmm(object, wObj,
theta0=NULL, algo=algoObj("optim"), ...)

## S4 method for signature 'sfunctionModel,sysMomentWeights'
solveGmm(object, wObj,
theta0=NULL, algo=algoObj("optim"), ...)

Arguments

object	A moment-based model
theta0	The vector of coefficients for the starting values used in optim. If NULL, the starting values in the object if used. For system of equations, it is a list of vectors.
wObj	An object of class "momentWeights" or "sysMomentWeights".
algo	The numerical algorithm to minimize the objective function. It must be a class minAlgo object created by algoObj.
...	Arguments to pass to optim.

Value

A list with the following:

theta	The vector of solution
convergence	convergence code. 0 means normal convergence. For higher numbers, see optim

Methods

signature(object = "allNLMoment", wObj = "momentWeights")

Method to solve either nonlinear regressions or models in which moments are computed with a function. The objective is minimized using optim.

signature(object = "rnonlinearModel", wObj = "momentWeights")

Method to solve restricted nonlinear models. It computes the analytical solution.

signature(object = "linearModel", wObj = "momentWeights")

Method to solve linear models. It computes the analytical solution.

signature(object = "slinearModel", wObj = "sysMomentWeights")

Method to solve system of linear models. It computes the analytical solution.

signature(object = "rslinearModel", wObj = "sysMomentWeights")

Method to solve system of linear models in which restrictions have been imposed on the coefficients. It computes the analytical solution.

signature(object = "slinearModel", wObj = "sysMomentWeights")

Method to solve system of nonlinear models. The solution is obtained with optim using the analytical derivatives.

Examples

data(simData)
theta <- c(beta0=1,beta1=2)
model1 <- momentModel(y~x1, ~z1+z2, data=simData)

## A manual two-step GMM
w0 <- evalWeights(model1, w="ident")
theta0 <- solveGmm(model1, w0)$theta
w <- evalWeights(model1, theta0)
theta1 <- solveGmm(model1, w)$theta 

momentfit documentation built on June 26, 2024, 3 p.m.