GetParameterMatrix {ggdmc}

Constructs a ns x npar matrix,

Description

The matrix is used to simulate data. Each row represents one set of parameters for a participant.

Usage

GetParameterMatrix(x, nsub, prior = NA, ps = NA, seed = NULL)

Arguments

x

a model object

nsub

number of subjects.

prior

a prior object

ps

a vector or a matirx.

seed

an integer specifying a random seed.

Details

One must enter either a vector or a matrix as true parameters to the argument, ps, when presuming to simulate data based on a fixed-effect model. When the assumption is to simulate data based on a random-effect model, one must enter a prior object to the argument, prior to first randomly generate a true parameter matrix.

Value

a ns x npar matrix

Examples

model <- BuildModel(
p.map     = list(a ="1", v = "1",z = "1", d = "1", sz = "1", sv = "1",
            t0 = "1", st0 = "1"),
match.map = list(M = list(s1 = "r1", s2 ="r2")),
factors   = list(S = c("s1", "s2")),
constants = c(st0 = 0, d = 0),
responses = c("r1", "r2"),
type      = "rd")

p.prior <- BuildPrior(
  dists = c("tnorm", "tnorm", "beta", "beta", "tnorm", "beta"),
  p1    = c(a = 1, v = 0, z = 1, sz = 1, sv = 1, t0 = 1),
  p2    = c(a = 1, v = 2, z = 1, sz = 1, sv = 1, t0 = 1),
  lower = c(0, -5, NA, NA, 0, NA),
  upper = c(2,  5, NA, NA, 2, NA))

## Example 1: Randomly generate 2 sets of true parameters from
## parameter priors (p.prior)
GetParameterMatrix(model, 2, p.prior)
##            a         v         z        sz       sv        t0
## [1,] 1.963067  1.472940 0.9509158 0.5145047 1.344705 0.0850591
## [2,] 1.512276 -1.995631 0.6981290 0.2626882 1.867853 0.1552828

## Example 2: Use a user-selected true parameters
true.vector  <- c(a=1, v=1, z=0.5, sz=0.2, sv=1, t0=.15)
GetParameterMatrix(model, 2, NA, true.vector)
##      a v   z  sz sv   t0
## [1,] 1 1 0.5 0.2  1 0.15
## [2,] 1 1 0.5 0.2  1 0.15
GetParameterMatrix(model, 2, ps = true.vector)

## Example 3: When a user enter arbritary sequence of parameters.
## Note sv is before sz. It should be sz before sv
## See correct sequence, by entering "attr(model, 'p.vector')"
## GetParameterMatrix will rearrange the sequence.
true.vector  <- c(a=1, v=1, z=0.5, sv=1, sz = .2, t0=.15)
GetParameterMatrix(model, 2, NA, true.vector)
##      a v   z  sz sv   t0
## [1,] 1 1 0.5 0.2  1 0.15
## [2,] 1 1 0.5 0.2  1 0.15