dtrt03.f3

!>
!> DTRT03 computes the residual for the solution to a scaled triangular
!> system of equations A*x = s*b  or  A'*x = s*b.
!> Here A is a triangular matrix, A' is the transpose of A, s is a
!> scalar, and x and b are N by NRHS matrices.  The test ratio is the
!> maximum over the number of right hand sides of
!>    norm(s*b - op(A)*x) / ( norm(op(A)) * norm(x) * EPS ),
!> where op(A) denotes A or A' and EPS is the machine epsilon.
!> 

UPLO

!>          UPLO is CHARACTER*1
!>          Specifies whether the matrix A is upper or lower triangular.
!>          = 'U':  Upper triangular
!>          = 'L':  Lower triangular
!> 

TRANS

!>          TRANS is CHARACTER*1
!>          Specifies the operation applied to A.
!>          = 'N':  A *x = s*b  (No transpose)
!>          = 'T':  A'*x = s*b  (Transpose)
!>          = 'C':  A'*x = s*b  (Conjugate transpose = Transpose)
!> 

DIAG

!>          DIAG is CHARACTER*1
!>          Specifies whether or not the matrix A is unit triangular.
!>          = 'N':  Non-unit triangular
!>          = 'U':  Unit triangular
!> 

N

!>          N is INTEGER
!>          The order of the matrix A.  N >= 0.
!> 

NRHS

!>          NRHS is INTEGER
!>          The number of right hand sides, i.e., the number of columns
!>          of the matrices X and B.  NRHS >= 0.
!> 

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The triangular matrix A.  If UPLO = 'U', the leading n by n
!>          upper triangular part of the array A contains the upper
!>          triangular matrix, and the strictly lower triangular part of
!>          A is not referenced.  If UPLO = 'L', the leading n by n lower
!>          triangular part of the array A contains the lower triangular
!>          matrix, and the strictly upper triangular part of A is not
!>          referenced.  If DIAG = 'U', the diagonal elements of A are
!>          also not referenced and are assumed to be 1.
!> 

LDA

!>          LDA is INTEGER
!>          The leading dimension of the array A.  LDA >= max(1,N).
!> 

SCALE

!>          SCALE is DOUBLE PRECISION
!>          The scaling factor s used in solving the triangular system.
!> 

CNORM

!>          CNORM is DOUBLE PRECISION array, dimension (N)
!>          The 1-norms of the columns of A, not counting the diagonal.
!> 

TSCAL

!>          TSCAL is DOUBLE PRECISION
!>          The scaling factor used in computing the 1-norms in CNORM.
!>          CNORM actually contains the column norms of TSCAL*A.
!> 

X

!>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
!>          The computed solution vectors for the system of linear
!>          equations.
!> 

LDX

!>          LDX is INTEGER
!>          The leading dimension of the array X.  LDX >= max(1,N).
!> 

B

!>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
!>          The right hand side vectors for the system of linear
!>          equations.
!> 

LDB

!>          LDB is INTEGER
!>          The leading dimension of the array B.  LDB >= max(1,N).
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (N)
!> 

RESID

!>          RESID is DOUBLE PRECISION
!>          The maximum over the number of right hand sides of
!>          norm(op(A)*x - s*b) / ( norm(op(A)) * norm(x) * EPS ).
!> 

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