SSYT22  generally checks a decomposition of the form


              A U = U S


      where A is symmetric, the columns of U are orthonormal, and S


      is diagonal (if KBAND=0) or symmetric tridiagonal (if


      KBAND=1).  If ITYPE=1, then U is represented as a dense matrix,


      otherwise the U is expressed as a product of Householder


      transformations, whose vectors are stored in the array 'V' and


      whose scaling constants are in 'TAU'; we shall use the letter


      'V' to refer to the product of Householder transformations


      (which should be equal to U).


      Specifically, if ITYPE=1, then:


              RESULT(1) = | U**T A U - S | / ( |A| m ulp ) and


              RESULT(2) = | I - U**T U | / ( m ulp )

  ITYPE   INTEGER


          Specifies the type of tests to be performed.


          1: U expressed as a dense orthogonal matrix:


             RESULT(1) = | A - U S U**T | / ( |A| n ulp ) and


             RESULT(2) = | I - U U**T | / ( n ulp )


  UPLO    CHARACTER


          If UPLO='U', the upper triangle of A will be used and the


          (strictly) lower triangle will not be referenced.  If


          UPLO='L', the lower triangle of A will be used and the


          (strictly) upper triangle will not be referenced.


          Not modified.


  N       INTEGER


          The size of the matrix.  If it is zero, SSYT22 does nothing.


          It must be at least zero.


          Not modified.


  M       INTEGER


          The number of columns of U.  If it is zero, SSYT22 does


          nothing.  It must be at least zero.


          Not modified.


  KBAND   INTEGER


          The bandwidth of the matrix.  It may only be zero or one.


          If zero, then S is diagonal, and E is not referenced.  If


          one, then S is symmetric tri-diagonal.


          Not modified.


  A       REAL array, dimension (LDA , N)


          The original (unfactored) matrix.  It is assumed to be


          symmetric, and only the upper (UPLO='U') or only the lower


          (UPLO='L') will be referenced.


          Not modified.


  LDA     INTEGER


          The leading dimension of A.  It must be at least 1


          and at least N.


          Not modified.


  D       REAL array, dimension (N)


          The diagonal of the (symmetric tri-) diagonal matrix.


          Not modified.


  E       REAL array, dimension (N)


          The off-diagonal of the (symmetric tri-) diagonal matrix.


          E(1) is ignored, E(2) is the (1,2) and (2,1) element, etc.


          Not referenced if KBAND=0.


          Not modified.


  U       REAL array, dimension (LDU, N)


          If ITYPE=1 or 3, this contains the orthogonal matrix in


          the decomposition, expressed as a dense matrix.  If ITYPE=2,


          then it is not referenced.


          Not modified.


  LDU     INTEGER


          The leading dimension of U.  LDU must be at least N and


          at least 1.


          Not modified.


  V       REAL array, dimension (LDV, N)


          If ITYPE=2 or 3, the lower triangle of this array contains


          the Householder vectors used to describe the orthogonal


          matrix in the decomposition.  If ITYPE=1, then it is not


          referenced.


          Not modified.


  LDV     INTEGER


          The leading dimension of V.  LDV must be at least N and


          at least 1.


          Not modified.


  TAU     REAL array, dimension (N)


          If ITYPE >= 2, then TAU(j) is the scalar factor of


          v(j) v(j)**T in the Householder transformation H(j) of


          the product  U = H(1)...H(n-2)


          If ITYPE < 2, then TAU is not referenced.


          Not modified.


  WORK    REAL array, dimension (2*N**2)


          Workspace.


          Modified.


  RESULT  REAL array, dimension (2)


          The values computed by the two tests described above.  The


          values are currently limited to 1/ulp, to avoid overflow.


          RESULT(1) is always modified.  RESULT(2) is modified only


          if LDU is at least N.


          Modified.

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