sget53.f3

!>
!> SGET53  checks the generalized eigenvalues computed by SLAG2.
!>
!> The basic test for an eigenvalue is:
!>
!>                              | det( s A - w B ) |
!>     RESULT =  ---------------------------------------------------
!>               ulp max( s norm(A), |w| norm(B) )*norm( s A - w B )
!>
!> Two  are performed:
!>
!> (1)  ulp*max( s*norm(A), |w|*norm(B) )  must be at least
!>      safe_minimum.  This insures that the test performed is
!>      not essentially  det(0*A + 0*B)=0.
!>
!> (2)  s*norm(A) + |w|*norm(B) must be less than 1/safe_minimum.
!>      This insures that  s*A - w*B  will not overflow.
!>
!> If these tests are not passed, then  s  and  w  are scaled and
!> tested anyway, if this is possible.
!> 

A

!>          A is REAL array, dimension (LDA, 2)
!>          The 2x2 matrix A.
!> 

LDA

!>          LDA is INTEGER
!>          The leading dimension of A.  It must be at least 2.
!> 

B

!>          B is REAL array, dimension (LDB, N)
!>          The 2x2 upper-triangular matrix B.
!> 

LDB

!>          LDB is INTEGER
!>          The leading dimension of B.  It must be at least 2.
!> 

SCALE

!>          SCALE is REAL
!>          The  s in the formula  s A - w B .  It is
!>          assumed to be non-negative.
!> 

WR

!>          WR is REAL
!>          The real part of the eigenvalue  w  in the formula
!>          s A - w B .
!> 

WI

!>          WI is REAL
!>          The imaginary part of the eigenvalue  w  in the formula
!>          s A - w B .
!> 

RESULT

!>          RESULT is REAL
!>          If INFO is 2 or less, the value computed by the test
!>             described above.
!>          If INFO=3, this will just be 1/ulp.
!> 

INFO

!>          INFO is INTEGER
!>          =0:  The input data pass the .
!>          =1:  s*norm(A) + |w|*norm(B) > 1/safe_minimum.
!>          =2:  ulp*max( s*norm(A), |w|*norm(B) ) < safe_minimum
!>          =3:  same as INFO=2, but  s  and  w  could not be scaled so
!>               as to compute the test.
!> 

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