register_trend: Register a custom C++ trend kernel

In EMC2: Bayesian Hierarchical Analysis of Cognitive Models of Choice

Register a custom C++ trend kernel

Description

Compiles and registers a user-provided C++ function that maps per-trial kernel parameters and inputs to a numeric vector. The C++ function must have signature: NumericVector f(NumericMatrix trend_pars, NumericMatrix input) and provide an exported pointer creator using EMC2_MAKE_PTR.

Usage

register_trend(trend_parameters, file, transforms = NULL, base = "add")

Arguments

trend_parameters	Character vector of kernel parameter names (in order).
file	Path to the C++ file implementing the custom kernel. The file should include EMC2/userfun.hpp and define a pointer creator (via EMC2_MAKE_PTR) that is exported to R.
transforms	Optional named character vector or list mapping each custom kernel parameter name to a transform name (e.g., "identity", "exp", "pnorm"). Length must match trend_parameters. If unnamed but the correct length, the order is assumed to match trend_parameters.
base	Default base to use when creating trends with this custom kernel if no bases argument is supplied to make_trend. One of c("lin","exp_lin","centered","add","identity"). Default "add".

Value

An object to pass to make_trend(custom_trend=...), carrying the pointer, parameter names, default base, and optional transform mapping.

EMC2 documentation built on Dec. 2, 2025, 9:06 a.m.