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/* dlauu2.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
#include "blaswrap.h"
/* Table of constant values */
static doublereal c_b7 = 1.;
static integer c__1 = 1;
/* Subroutine */ int dlauu2_(char *uplo, integer *n, doublereal *a, integer *
lda, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2, i__3;
/* Local variables */
integer i__;
doublereal aii;
extern doublereal ddot_(integer *, doublereal *, integer *, doublereal *,
integer *);
extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
integer *);
extern logical lsame_(char *, char *);
extern /* Subroutine */ int dgemv_(char *, integer *, integer *,
doublereal *, doublereal *, integer *, doublereal *, integer *,
doublereal *, doublereal *, integer *);
logical upper;
extern /* Subroutine */ int xerbla_(char *, integer *);
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* DLAUU2 computes the product U * U' or L' * L, where the triangular */
/* factor U or L is stored in the upper or lower triangular part of */
/* the array A. */
/* If UPLO = 'U' or 'u' then the upper triangle of the result is stored, */
/* overwriting the factor U in A. */
/* If UPLO = 'L' or 'l' then the lower triangle of the result is stored, */
/* overwriting the factor L in A. */
/* This is the unblocked form of the algorithm, calling Level 2 BLAS. */
/* Arguments */
/* ========= */
/* UPLO (input) CHARACTER*1 */
/* Specifies whether the triangular factor stored in the array A */
/* is upper or lower triangular: */
/* = 'U': Upper triangular */
/* = 'L': Lower triangular */
/* N (input) INTEGER */
/* The order of the triangular factor U or L. N >= 0. */
/* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
/* On entry, the triangular factor U or L. */
/* On exit, if UPLO = 'U', the upper triangle of A is */
/* overwritten with the upper triangle of the product U * U'; */
/* if UPLO = 'L', the lower triangle of A is overwritten with */
/* the lower triangle of the product L' * L. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -k, the k-th argument had an illegal value */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
/* Function Body */
*info = 0;
upper = lsame_(uplo, "U");
if (! upper && ! lsame_(uplo, "L")) {
*info = -1;
} else if (*n < 0) {
*info = -2;
} else if (*lda < max(1,*n)) {
*info = -4;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("DLAUU2", &i__1);
return 0;
}
/* Quick return if possible */
if (*n == 0) {
return 0;
}
if (upper) {
/* Compute the product U * U'. */
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
aii = a[i__ + i__ * a_dim1];
if (i__ < *n) {
i__2 = *n - i__ + 1;
a[i__ + i__ * a_dim1] = ddot_(&i__2, &a[i__ + i__ * a_dim1],
lda, &a[i__ + i__ * a_dim1], lda);
i__2 = i__ - 1;
i__3 = *n - i__;
dgemv_("No transpose", &i__2, &i__3, &c_b7, &a[(i__ + 1) *
a_dim1 + 1], lda, &a[i__ + (i__ + 1) * a_dim1], lda, &
aii, &a[i__ * a_dim1 + 1], &c__1);
} else {
dscal_(&i__, &aii, &a[i__ * a_dim1 + 1], &c__1);
}
/* L10: */
}
} else {
/* Compute the product L' * L. */
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
aii = a[i__ + i__ * a_dim1];
if (i__ < *n) {
i__2 = *n - i__ + 1;
a[i__ + i__ * a_dim1] = ddot_(&i__2, &a[i__ + i__ * a_dim1], &
c__1, &a[i__ + i__ * a_dim1], &c__1);
i__2 = *n - i__;
i__3 = i__ - 1;
dgemv_("Transpose", &i__2, &i__3, &c_b7, &a[i__ + 1 + a_dim1],
lda, &a[i__ + 1 + i__ * a_dim1], &c__1, &aii, &a[i__
+ a_dim1], lda);
} else {
dscal_(&i__, &aii, &a[i__ + a_dim1], lda);
}
/* L20: */
}
}
return 0;
/* End of DLAUU2 */
} /* dlauu2_ */
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