.TH "dgeqr2.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*-
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.SH NAME
dgeqr2.f \- 
.SH SYNOPSIS
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.SS "Functions/Subroutines"

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.RI "subroutine \fBdgeqr2\fP (M, N, A, LDA, TAU, WORK, INFO)"
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.RI "\fI\fBDGEQR2\fP computes the QR factorization of a general rectangular matrix using an unblocked algorithm\&. \fP"
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.SH "Function/Subroutine Documentation"
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.SS "subroutine dgeqr2 (integerM, integerN, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK, integerINFO)"

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\fBDGEQR2\fP computes the QR factorization of a general rectangular matrix using an unblocked algorithm\&.  
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\fBPurpose: \fP
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.nf
 DGEQR2 computes a QR factorization of a real m by n matrix A:
 A = Q * R.
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.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.
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\fIN\fP 
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          N is INTEGER
          The number of columns of the matrix A.  N >= 0.
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\fIA\fP 
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          A is DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the m by n matrix A.
          On exit, the elements on and above the diagonal of the array
          contain the min(m,n) by n upper trapezoidal matrix R (R is
          upper triangular if m >= n); the elements below the diagonal,
          with the array TAU, represent the orthogonal matrix Q as a
          product of elementary reflectors (see Further Details).
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\fILDA\fP 
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          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,M).
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\fITAU\fP 
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          TAU is DOUBLE PRECISION array, dimension (min(M,N))
          The scalar factors of the elementary reflectors (see Further
          Details).
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\fIWORK\fP 
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          WORK is DOUBLE PRECISION array, dimension (N)
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\fIINFO\fP 
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          INFO is INTEGER
          = 0: successful exit
          < 0: if INFO = -i, the i-th argument had an illegal value
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.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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\fBDate:\fP
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September 2012 
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\fBFurther Details: \fP
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  The matrix Q is represented as a product of elementary reflectors

     Q = H(1) H(2) . . . H(k), 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:m) is stored on exit in A(i+1:m,i),
  and tau in TAU(i).
.fi
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.RE
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Definition at line 122 of file dgeqr2\&.f\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.