Processes a model formula and a data frame to generate design matrices (X and Z)
and a response vector (y) for regression models, including support for complex
formulas with | operators.
makeXZy(formula, df)A list containing the following components:
XA design matrix for the main predictors.
ZA design matrix for additional predictors (e.g., for a secondary process in a two-component model).
yThe response vector extracted from the formula.
A symbolic description of the model, where the left-hand side specifies
the response variable and the right-hand side specifies predictors.
Formulas can include a | operator to separate predictors for different components of a model.
A data frame containing the variables specified in the formula.
This function processes the formula to extract and construct:
X: The main design matrix.
Z: A secondary design matrix (if a | operator is used in the formula, separating components).
y: The response variable.
It handles cases where the formula specifies:
Only the main component (e.g., y ~ x1 + x2).
A secondary component using the | operator (e.g., y ~ x1 + x2 | z1 + z2).