Skip to contents

Diffusion Model Components

Source: R/models.R
component_shelf.Rd

This function is meant as a convenient way to access pre-built model component functions.

Usage

component_shelf()

Value

A list of the respective functions; each entry/function can be accessed by "name" (see the Example and Details).

Details

The function provides the following functions:

  • mu_constant, provides the component function for a constant drift rate with parameter muc.

  • mu_dmc, provides the drift rate of the superimposed diffusion process of DMC. Necessary parameters are muc (drift rate of the controlled process), a (shape..), A (amplitude...), tau (scale of the automatic process).

  • mu_ssp, provides the drift rate for SSP. Necessary parameters are p (perceptual input of flankers and target), sd_0 (initial spotlight width), r (shrinking rate of the spotlight) and 'sign' (an auxiliary parameter for controlling the contribution of the flanker stimuli). Note that no mu_int_ssp exists.

  • mu_int_constant, provides the complementary integral to mu_constant.

  • mu_int_dmc, provides the complementary integral to mu_dmc.

  • x_dirac_0, provides a dirac delta for a starting point centered between the boundaries (no parameter required).

  • x_uniform, provides a uniform distribution for a start point centered between the boundaries. Requires a parameter range_start (between 0 and 2).

  • x_beta, provides the function component for a symmetric beta-shaped starting point distribution with parameter alpha.

  • b_constant, provides a constant boundary with parameter b.

  • b_hyperbol, provides a collapsing boundary in terms of a hyperbolic ratio function with parameters b0 as the initial value of the (upper) boundary, kappa the size of the collapse, and t05 the point in time where the boundary has collapsed by half.

  • b_weibull, provides a collapsing boundary in terms of a Weibull distribution with parameters b0 as the initial value of the (upper) boundary, lambda controlling the time of the collapse, k the shape of the collapse, and kappa the size of the collapse.

  • dt_b_constant, the first derivative of b_constant.

  • dt_b_hyperbol, the first derivative of b_hyperbol.

  • nt_constant, provides a constant non-decision time with parameter non_dec.

  • nt_uniform, provides a uniform distribution for the non-decision time. Requires the parameters non_dec and range_non_dec.

  • nt_truncated_normal, provides the component function for a normally distributed non-decision time with parameters non_dec, sd_non_dec. The Distribution is truncated to \([0, t_{max}]\).

  • dummy_t a function that accepts all required arguments for mu_fun or mu_int_fun but which throws an error. Might come in handy when a user doesn't require the integral of the drift rate.

See vignette("customize_ddms", "dRiftDM") for more information on how to set/modify/customize the components of a diffusion model.

Examples

pre_built_functions <- component_shelf()
names(pre_built_functions)
#>  [1] "mu_constant"         "mu_dmc"              "mu_ssp"             
#>  [4] "mu_int_constant"     "mu_int_dmc"          "x_dirac_0"          
#>  [7] "x_beta"              "x_uniform"           "b_constant"         
#> [10] "b_hyperbol"          "b_weibull"           "dt_b_constant"      
#> [13] "dt_b_hyperbol"       "dt_b_weibull"        "nt_constant"        
#> [16] "nt_uniform"          "nt_truncated_normal" "dummy_t"