dlasd5(3) on Linux
The text 7bac7d421cda, as Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
subroutine computes the square root of the I-th eigenvalue of a positive symmetric rank-one modification of a 2-by-2 diagonal matrix diag( D ) * diag( D ) + RHO * Z * transpose(Z)