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---
:name: cgelq2
:md5sum: b8fcc5877fd42da3a6c7800e8a8bec97
:category: :subroutine
:arguments:
- m:
:type: integer
:intent: input
- n:
:type: integer
:intent: input
- a:
:type: complex
:intent: input/output
:dims:
- lda
- n
- lda:
:type: integer
:intent: input
- tau:
:type: complex
:intent: output
:dims:
- MIN(m,n)
- work:
:type: complex
:intent: workspace
:dims:
- m
- info:
:type: integer
:intent: output
:substitutions:
m: lda
:fortran_help: " SUBROUTINE CGELQ2( M, N, A, LDA, TAU, WORK, INFO )\n\n\
* Purpose\n\
* =======\n\
*\n\
* CGELQ2 computes an LQ factorization of a complex m by n matrix A:\n\
* A = L * Q.\n\
*\n\n\
* Arguments\n\
* =========\n\
*\n\
* M (input) INTEGER\n\
* The number of rows of the matrix A. M >= 0.\n\
*\n\
* N (input) INTEGER\n\
* The number of columns of the matrix A. N >= 0.\n\
*\n\
* A (input/output) COMPLEX array, dimension (LDA,N)\n\
* On entry, the m by n matrix A.\n\
* On exit, the elements on and below the diagonal of the array\n\
* contain the m by min(m,n) lower trapezoidal matrix L (L is\n\
* lower triangular if m <= n); the elements above the diagonal,\n\
* with the array TAU, represent the unitary matrix Q as a\n\
* product of elementary reflectors (see Further Details).\n\
*\n\
* LDA (input) INTEGER\n\
* The leading dimension of the array A. LDA >= max(1,M).\n\
*\n\
* TAU (output) COMPLEX array, dimension (min(M,N))\n\
* The scalar factors of the elementary reflectors (see Further\n\
* Details).\n\
*\n\
* WORK (workspace) COMPLEX array, dimension (M)\n\
*\n\
* INFO (output) INTEGER\n\
* = 0: successful exit\n\
* < 0: if INFO = -i, the i-th argument had an illegal value\n\
*\n\n\
* Further Details\n\
* ===============\n\
*\n\
* The matrix Q is represented as a product of elementary reflectors\n\
*\n\
* Q = H(k)' . . . H(2)' H(1)', where k = min(m,n).\n\
*\n\
* Each H(i) has the form\n\
*\n\
* H(i) = I - tau * v * v'\n\
*\n\
* where tau is a complex scalar, and v is a complex vector with\n\
* v(1:i-1) = 0 and v(i) = 1; conjg(v(i+1:n)) is stored on exit in\n\
* A(i,i+1:n), and tau in TAU(i).\n\
*\n\
* =====================================================================\n\
*\n"
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