LAPACK 3.12.0
LAPACK: Linear Algebra PACKage

Functions  
subroutine  dlaexc (wantq, n, t, ldt, q, ldq, j1, n1, n2, work, info) 
DLAEXC swaps adjacent diagonal blocks of a real upper quasitriangular matrix in Schur canonical form, by an orthogonal similarity transformation.  
subroutine  slaexc (wantq, n, t, ldt, q, ldq, j1, n1, n2, work, info) 
SLAEXC swaps adjacent diagonal blocks of a real upper quasitriangular matrix in Schur canonical form, by an orthogonal similarity transformation.  