.TH "SRC/zlaqp2.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
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.SH NAME
SRC/zlaqp2.f
.SH SYNOPSIS
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.PP
.SS "Functions/Subroutines"

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.ti -1c
.RI "subroutine \fBzlaqp2\fP (m, n, offset, a, lda, jpvt, tau, vn1, vn2, work)"
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.RI "\fBZLAQP2\fP computes a QR factorization with column pivoting of the matrix block\&. "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine zlaqp2 (integer m, integer n, integer offset, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * ) jpvt, complex*16, dimension( * ) tau, double precision, dimension( * ) vn1, double precision, dimension( * ) vn2, complex*16, dimension( * ) work)"

.PP
\fBZLAQP2\fP computes a QR factorization with column pivoting of the matrix block\&.  
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\fBPurpose:\fP
.RS 4

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.nf
!>
!> ZLAQP2 computes a QR factorization with column pivoting of
!> the block A(OFFSET+1:M,1:N)\&.
!> The block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized\&.
!> 
.fi
.PP
 
.RE
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\fBParameters\fP
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\fIM\fP 
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!>          M is INTEGER
!>          The number of rows of the matrix A\&. M >= 0\&.
!> 
.fi
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.br
\fIN\fP 
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.nf
!>          N is INTEGER
!>          The number of columns of the matrix A\&. N >= 0\&.
!> 
.fi
.PP
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\fIOFFSET\fP 
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!>          OFFSET is INTEGER
!>          The number of rows of the matrix A that must be pivoted
!>          but no factorized\&. OFFSET >= 0\&.
!> 
.fi
.PP
.br
\fIA\fP 
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!>          A is COMPLEX*16 array, dimension (LDA,N)
!>          On entry, the M-by-N matrix A\&.
!>          On exit, the upper triangle of block A(OFFSET+1:M,1:N) is
!>          the triangular factor obtained; the elements in block
!>          A(OFFSET+1:M,1:N) below the diagonal, together with the
!>          array TAU, represent the orthogonal matrix Q as a product of
!>          elementary reflectors\&. Block A(1:OFFSET,1:N) has been
!>          accordingly pivoted, but no factorized\&.
!> 
.fi
.PP
.br
\fILDA\fP 
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!>          LDA is INTEGER
!>          The leading dimension of the array A\&. LDA >= max(1,M)\&.
!> 
.fi
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\fIJPVT\fP 
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!>          JPVT is INTEGER array, dimension (N)
!>          On entry, if JPVT(i) \&.ne\&. 0, the i-th column of A is permuted
!>          to the front of A*P (a leading column); if JPVT(i) = 0,
!>          the i-th column of A is a free column\&.
!>          On exit, if JPVT(i) = k, then the i-th column of A*P
!>          was the k-th column of A\&.
!> 
.fi
.PP
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\fITAU\fP 
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!>          TAU is COMPLEX*16 array, dimension (min(M,N))
!>          The scalar factors of the elementary reflectors\&.
!> 
.fi
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.br
\fIVN1\fP 
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.nf
!>          VN1 is DOUBLE PRECISION array, dimension (N)
!>          The vector with the partial column norms\&.
!> 
.fi
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.br
\fIVN2\fP 
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!>          VN2 is DOUBLE PRECISION array, dimension (N)
!>          The vector with the exact column norms\&.
!> 
.fi
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.br
\fIWORK\fP 
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.nf
!>          WORK is COMPLEX*16 array, dimension (N)
!> 
.fi
.PP
 
.RE
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\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 

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Univ\&. of California Berkeley 

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Univ\&. of Colorado Denver 

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NAG Ltd\&. 
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\fBContributors:\fP
.RS 4
G\&. Quintana-Orti, Depto\&. de Informatica, Universidad Jaime I, Spain X\&. Sun, Computer Science Dept\&., Duke University, USA 
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 Partial column norm updating strategy modified on April 2011 Z\&. Drmac and Z\&. Bujanovic, Dept\&. of Mathematics, University of Zagreb, Croatia\&. 
.RE
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\fBReferences:\fP
.RS 4
LAPACK Working Note 176  
.RE
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Definition at line \fB147\fP of file \fBzlaqp2\&.f\fP\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.