.TH "TESTING/LIN/dgtt02.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME TESTING/LIN/dgtt02.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdgtt02\fP (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)" .br .RI "\fBDGTT02\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dgtt02 (character trans, integer n, integer nrhs, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer ldb, double precision resid)" .PP \fBDGTT02\fP .PP \fBPurpose:\fP .RS 4 .PP .nf DGTT02 computes the residual for the solution to a tridiagonal system of equations: RESID = norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS), where EPS is the machine epsilon\&. The norm used is the 1-norm\&. .fi .PP .RE .PP \fBParameters\fP .RS 4 \fITRANS\fP .PP .nf TRANS is CHARACTER Specifies the form of the residual\&. = 'N': B - A * X (No transpose) = 'T': B - A**T * X (Transpose) = 'C': B - A**H * X (Conjugate transpose = Transpose) .fi .PP .br \fIN\fP .PP .nf N is INTEGER The order of the matrix A\&. N >= 0\&. .fi .PP .br \fINRHS\fP .PP .nf NRHS is INTEGER The number of right hand sides, i\&.e\&., the number of columns of the matrices B and X\&. NRHS >= 0\&. .fi .PP .br \fIDL\fP .PP .nf DL is DOUBLE PRECISION array, dimension (N-1) The (n-1) sub-diagonal elements of A\&. .fi .PP .br \fID\fP .PP .nf D is DOUBLE PRECISION array, dimension (N) The diagonal elements of A\&. .fi .PP .br \fIDU\fP .PP .nf DU is DOUBLE PRECISION array, dimension (N-1) The (n-1) super-diagonal elements of A\&. .fi .PP .br \fIX\fP .PP .nf X is DOUBLE PRECISION array, dimension (LDX,NRHS) The computed solution vectors X\&. .fi .PP .br \fILDX\fP .PP .nf LDX is INTEGER The leading dimension of the array X\&. LDX >= max(1,N)\&. .fi .PP .br \fIB\fP .PP .nf B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the right hand side vectors for the system of linear equations\&. On exit, B is overwritten with the difference B - op(A)*X\&. .fi .PP .br \fILDB\fP .PP .nf LDB is INTEGER The leading dimension of the array B\&. LDB >= max(1,N)\&. .fi .PP .br \fIRESID\fP .PP .nf RESID is DOUBLE PRECISION norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS) .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP .PP Definition at line \fB123\fP of file \fBdgtt02\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.