.TH "dgelq2.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME dgelq2.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdgelq2\fP (M, N, A, LDA, TAU, WORK, INFO)" .br .RI "\fI\fBDGELQ2\fP computes the LQ factorization of a general rectangular matrix using an unblocked algorithm\&. \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dgelq2 (integerM, integerN, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK, integerINFO)" .PP \fBDGELQ2\fP computes the LQ factorization of a general rectangular matrix using an unblocked algorithm\&. .PP \fBPurpose: \fP .RS 4 .PP .nf DGELQ2 computes an LQ factorization of a real m by n matrix A: A = L * Q. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIM\fP .PP .nf M is INTEGER The number of rows of the matrix A. M >= 0. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of columns of the matrix A. N >= 0. .fi .PP .br \fIA\fP .PP .nf A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the m by n matrix A. On exit, the elements on and below the diagonal of the array contain the m by min(m,n) lower trapezoidal matrix L (L is lower triangular if m <= n); the elements above the diagonal, with the array TAU, represent the orthogonal matrix Q as a product of elementary reflectors (see Further Details). .fi .PP .br \fILDA\fP .PP .nf LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). .fi .PP .br \fITAU\fP .PP .nf TAU is DOUBLE PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details). .fi .PP .br \fIWORK\fP .PP .nf WORK is DOUBLE PRECISION array, dimension (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 .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 \fBFurther Details: \fP .RS 4 .PP .nf The matrix Q is represented as a product of elementary reflectors Q = H(k) . . . H(2) H(1), where k = min(m,n). Each H(i) has the form H(i) = I - tau * v * v**T where tau is a real scalar, and v is a real vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:n) is stored on exit in A(i,i+1:n), and tau in TAU(i). .fi .PP .RE .PP .PP Definition at line 122 of file dgelq2\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.