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lib/algo/legacy/eig_sort.viv

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# Generated by tools/algo/legacy.py from the corpus: do not edit.
# lib/hf's eigenvalue sort: a selection sort that moves each eigenvector with its value.
# Element comparisons are routed through lib/algo/legacy/order.viv; nothing else changes.
from algo.legacy.order import lg_lt

# from lib/hf/eigen.viv: eig_sort

#| Sort the eigenvalues in `d` ascending, moving the columns of `V` with them.
#| Selection sort: n is at most a few dozen, and a stable, simple order is
#| what makes the members comparable.
def eig_sort(d: Arr, V: Arr, n) {
    for i to n - 1 {
        k = i
        p = d[i]
        for j to n {
            if j > i and lg_lt(d[j], p) {
                k = j
                p = d[j]
            }
        }
        if k != i {
            d[k] = d[i]
            d[i] = p
            t = V[:, i]
            V[:, i] = V[:, k]
            V[:, k] = t
        }
    }
    return 0
}