R Under development (unstable) (2025-05-22 r88223 ucrt) -- "Unsuffered Consequences"
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> 
>  set.seed(42)
> 
>  library(aster)
> 
>  a <- matrix(rnorm(1000), 5)
>  a <- apply(a, 1, cumsum)
>  a <- var(a)
> 
>  b <- .Call(aster:::C_pos_def_mat_inv, a)
> 
>  all.equal(b %*% a, diag(nrow(a)))
[1] TRUE
> 
> 
> proc.time()
   user  system elapsed 
   0.10    0.07    0.17