.TH "TESTING/LIN/dtpt06.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME TESTING/LIN/dtpt06.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdtpt06\fP (rcond, rcondc, uplo, diag, n, ap, work, rat)" .br .RI "\fBDTPT06\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dtpt06 (double precision rcond, double precision rcondc, character uplo, character diag, integer n, double precision, dimension( * ) ap, double precision, dimension( * ) work, double precision rat)" .PP \fBDTPT06\fP .PP \fBPurpose:\fP .RS 4 .PP .nf DTPT06 computes a test ratio comparing RCOND (the reciprocal condition number of a triangular matrix A) and RCONDC, the estimate computed by DTPCON\&. Information about the triangular matrix A is used if one estimate is zero and the other is non-zero to decide if underflow in the estimate is justified\&. .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIRCOND\fP .PP .nf RCOND is DOUBLE PRECISION The estimate of the reciprocal condition number obtained by forming the explicit inverse of the matrix A and computing RCOND = 1/( norm(A) * norm(inv(A)) )\&. .fi .PP .br \fIRCONDC\fP .PP .nf RCONDC is DOUBLE PRECISION The estimate of the reciprocal condition number computed by DTPCON\&. .fi .PP .br \fIUPLO\fP .PP .nf UPLO is CHARACTER Specifies whether the matrix A is upper or lower triangular\&. = 'U': Upper triangular = 'L': Lower triangular .fi .PP .br \fIDIAG\fP .PP .nf DIAG is CHARACTER Specifies whether or not the matrix A is unit triangular\&. = 'N': Non-unit triangular = 'U': Unit triangular .fi .PP .br \fIN\fP .PP .nf N is INTEGER The order of the matrix A\&. N >= 0\&. .fi .PP .br \fIAP\fP .PP .nf AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) The upper or lower triangular matrix A, packed columnwise in a linear array\&. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n\&. .fi .PP .br \fIWORK\fP .PP .nf WORK is DOUBLE PRECISION array, dimension (N) .fi .PP .br \fIRAT\fP .PP .nf RAT is DOUBLE PRECISION The test ratio\&. If both RCOND and RCONDC are nonzero, RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1\&. If RAT = 0, the two estimates are exactly the same\&. .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 \fB110\fP of file \fBdtpt06\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.