SLASY2 - solve for the N1 by N2 matrix X, 1 <= N1,N2 <= 2,
       in  op(TL)*X + ISGN*X*op(TR) = SCALE*B,


SYNOPSIS

       SUBROUTINE SLASY2( LTRANL, LTRANR, ISGN, N1, N2, TL, LDTL,
                          TR, LDTR, B, LDB, SCALE, X, LDX, XNORM,
                          INFO )

           LOGICAL        LTRANL, LTRANR

           INTEGER        INFO, ISGN, LDB, LDTL, LDTR,  LDX,  N1,
                          N2

           REAL           SCALE, XNORM

           REAL           B( LDB, * ), TL( LDTL, * ), TR( LDTR, *
                          ), X( LDX, * )


PURPOSE

       SLASY2 solves for the N1 by N2 matrix X, 1 <= N1,N2 <=  2,
       in  op(TL)*X  + ISGN*X*op(TR) = SCALE*B, where TL is N1 by
       N1, TR is N2 by N2, B is N1 by N2, and ISGN  =  1  or  -1.
       op(T) = T or T', where T' denotes the transpose of T.


ARGUMENTS

       LTRANL  (input) LOGICAL
               On  entry, LTRANL specifies the op(TL): = .FALSE.,
               op(TL) = TL, = .TRUE., op(TL) = TL'.

       LTRANR  (input) LOGICAL
               On entry, LTRANR specifies the op(TR): =  .FALSE.,
               op(TR) = TR, = .TRUE., op(TR) = TR'.

       ISGN    (input) INTEGER
               On  entry, ISGN specifies the sign of the equation
               as described before. ISGN may only be 1 or -1.

       N1      (input) INTEGER
               On entry, N1 specifies the order of matrix TL.  N1
               may only be 0, 1 or 2.

       N2      (input) INTEGER
               On entry, N2 specifies the order of matrix TR.  N2
               may only be 0, 1 or 2.

       TL      (input) REAL array, dimension (LDTL,2)
               On entry, TL contains an N1 by N1 matrix.

       LDTL    (input) INTEGER
               The leading dimension of the matrix  TL.  LDTL  >=
               max(1,N1).

               On entry, TR contains an N2 by N2 matrix.

       LDTR    (input) INTEGER
               The  leading  dimension  of the matrix TR. LDTR >=
               max(1,N2).

       B       (input) REAL array, dimension (LDB,2)
               On entry, the N1  by  N2  matrix  B  contains  the
               right-hand side of the equation.

       LDB     (input) INTEGER
               The  leading  dimension  of  the  matrix B. LDB >=
               max(1,N1).

       SCALE   (output) REAL
               On exit, SCALE contains the scale factor. SCALE is
               chosen  less  than  or  equal  to 1 to prevent the
               solution overflowing.

       X       (output) REAL array, dimension (LDX,2)
               On exit, X contains the N1 by N2 solution.

       LDX     (input) INTEGER
               The leading dimension of  the  matrix  X.  LDX  >=
               max(1,N1).

       XNORM   (output) REAL
               On  exit,  XNORM is the infinity-norm of the solu­
               tion.

       INFO    (output) INTEGER
               On exit, INFO is set to 0: successful exit.
               1: TL and TR have too close eigenvalues, so TL  or
               TR  is  perturbed  to  get a nonsingular equation.
               NOTE: In the interests of speed, this routine does
               not check the inputs for errors.


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