103 SUBROUTINE dlae2( A, B, C, RT1, RT2 )
111 DOUBLE PRECISION A, B, C, RT1, RT2
118 parameter ( one = 1.0d0 )
120 parameter ( two = 2.0d0 )
121 DOUBLE PRECISION ZERO
122 parameter ( zero = 0.0d0 )
123 DOUBLE PRECISION HALF
124 parameter ( half = 0.5d0 )
127 DOUBLE PRECISION AB, ACMN, ACMX, ADF, DF, RT, SM, TB
141 IF( abs( a ).GT.abs( c ) )
THEN
149 rt = adf*sqrt( one+( ab / adf )**2 )
150 ELSE IF( adf.LT.ab )
THEN
151 rt = ab*sqrt( one+( adf / ab )**2 )
158 IF( sm.LT.zero )
THEN
165 rt2 = ( acmx / rt1 )*acmn - ( b / rt1 )*b
166 ELSE IF( sm.GT.zero )
THEN
173 rt2 = ( acmx / rt1 )*acmn - ( b / rt1 )*b
subroutine dlae2(A, B, C, RT1, RT2)
DLAE2 computes the eigenvalues of a 2-by-2 symmetric matrix.