.TH "dlasd0.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME dlasd0.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdlasd0\fP (N, SQRE, D, E, U, LDU, VT, LDVT, SMLSIZ, IWORK, WORK, INFO)" .br .RI "\fI\fBDLASD0\fP computes the singular values of a real upper bidiagonal n-by-m matrix B with diagonal d and off-diagonal e\&. Used by sbdsdc\&. \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dlasd0 (integerN, integerSQRE, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension( ldu, * )U, integerLDU, double precision, dimension( ldvt, * )VT, integerLDVT, integerSMLSIZ, integer, dimension( * )IWORK, double precision, dimension( * )WORK, integerINFO)" .PP \fBDLASD0\fP computes the singular values of a real upper bidiagonal n-by-m matrix B with diagonal d and off-diagonal e\&. Used by sbdsdc\&. .PP \fBPurpose: \fP .RS 4 .PP .nf Using a divide and conquer approach, DLASD0 computes the singular value decomposition (SVD) of a real upper bidiagonal N-by-M matrix B with diagonal D and offdiagonal E, where M = N + SQRE. The algorithm computes orthogonal matrices U and VT such that B = U * S * VT. The singular values S are overwritten on D. A related subroutine, DLASDA, computes only the singular values, and optionally, the singular vectors in compact form. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIN\fP .PP .nf N is INTEGER On entry, the row dimension of the upper bidiagonal matrix. This is also the dimension of the main diagonal array D. .fi .PP .br \fISQRE\fP .PP .nf SQRE is INTEGER Specifies the column dimension of the bidiagonal matrix. = 0: The bidiagonal matrix has column dimension M = N; = 1: The bidiagonal matrix has column dimension M = N+1; .fi .PP .br \fID\fP .PP .nf D is DOUBLE PRECISION array, dimension (N) On entry D contains the main diagonal of the bidiagonal matrix. On exit D, if INFO = 0, contains its singular values. .fi .PP .br \fIE\fP .PP .nf E is DOUBLE PRECISION array, dimension (M-1) Contains the subdiagonal entries of the bidiagonal matrix. On exit, E has been destroyed. .fi .PP .br \fIU\fP .PP .nf U is DOUBLE PRECISION array, dimension at least (LDQ, N) On exit, U contains the left singular vectors. .fi .PP .br \fILDU\fP .PP .nf LDU is INTEGER On entry, leading dimension of U. .fi .PP .br \fIVT\fP .PP .nf VT is DOUBLE PRECISION array, dimension at least (LDVT, M) On exit, VT**T contains the right singular vectors. .fi .PP .br \fILDVT\fP .PP .nf LDVT is INTEGER On entry, leading dimension of VT. .fi .PP .br \fISMLSIZ\fP .PP .nf SMLSIZ is INTEGER On entry, maximum size of the subproblems at the bottom of the computation tree. .fi .PP .br \fIIWORK\fP .PP .nf IWORK is INTEGER work array. Dimension must be at least (8 * N) .fi .PP .br \fIWORK\fP .PP .nf WORK is DOUBLE PRECISION work array. Dimension must be at least (3 * M**2 + 2 * M) .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value. > 0: if INFO = 1, a singular value did not converge .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 \fBDate:\fP .RS 4 September 2012 .RE .PP \fBContributors: \fP .RS 4 Ming Gu and Huan Ren, Computer Science Division, University of California at Berkeley, USA .RE .PP .PP Definition at line 152 of file dlasd0\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.