Precompute Workspace for Optimized Mixed Model

Performs expensive matrix computations that don't depend on the response vector, allowing for efficient reuse across multiple voxels.

Usage

mixed_precompute(X, Z, K = NULL)

Arguments

X

Fixed effects design matrix (n × p)

Z

Random effects design matrix (n × q)

K

Kinship/covariance matrix for random effects (q × q)

Value

Workspace object for use with mixed_solve_optimized

Examples

X <- matrix(1, 6, 1)
Z <- diag(6)
ws <- mixed_precompute(X, Z)
#> Workspace precomputed successfully:
#>   - n=6, p=1, q=6
#>   - Effective rank: 5
#>   - Using identity K: yes
names(ws)
#>  [1] "Q"              "U"              "phi"            "theta"         
#>  [5] "X_orig"         "Z_orig"         "XtXinv"         "n"             
#>  [9] "p"              "q"              "use_identity_K"