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LAPACK version 3.0
dlasy2(3)

PURPOSE
  DLASY2 - solve for the N1 by N2 matrix X, 1 <= N1,N2 <= 2, in	 op(TL)*X +
  ISGN*X*op(TR) = SCALE*B,

SYNTAX
  SUBROUTINE DLASY2( 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

      DOUBLE	     PRECISION SCALE, XNORM

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

DESCRIPTION
  DLASY2 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) DOUBLE PRECISION 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).

  TR	  (input) DOUBLE PRECISION array, dimension (LDTR,2)
	  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) DOUBLE PRECISION 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) DOUBLE PRECISION
	  On exit, SCALE contains the scale factor. SCALE is chosen less than
	  or equal to 1 to prevent the solution overflowing.

  X	  (output) DOUBLE PRECISION 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) DOUBLE PRECISION
	  On exit, XNORM is the infinity-norm of the solution.

  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.