/* sggglm.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 integer c__1 = 1;
static integer c_n1 = -1;
static real c_b32 = -1.f;
static real c_b34 = 1.f;
/* Subroutine */ int sggglm_(integer *n, integer *m, integer *p, real *a,
integer *lda, real *b, integer *ldb, real *d__, real *x, real *y,
real *work, integer *lwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, b_dim1, b_offset, i__1, i__2, i__3, i__4;
/* Local variables */
integer i__, nb, np, nb1, nb2, nb3, nb4, lopt;
extern /* Subroutine */ int sgemv_(char *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *), scopy_(integer *, real *, integer *, real *, integer *),
xerbla_(char *, integer *);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
extern /* Subroutine */ int sggqrf_(integer *, integer *, integer *, real
*, integer *, real *, real *, integer *, real *, real *, integer *
, integer *);
integer lwkmin, lwkopt;
logical lquery;
extern /* Subroutine */ int sormqr_(char *, char *, integer *, integer *,
integer *, real *, integer *, real *, real *, integer *, real *,
integer *, integer *), sormrq_(char *, char *,
integer *, integer *, integer *, real *, integer *, real *, real *
, integer *, real *, integer *, integer *),
strtrs_(char *, char *, char *, integer *, integer *, real *,
integer *, real *, integer *, integer *);
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SGGGLM solves a general Gauss-Markov linear model (GLM) problem: */
/* minimize || y ||_2 subject to d = A*x + B*y */
/* x */
/* where A is an N-by-M matrix, B is an N-by-P matrix, and d is a */
/* given N-vector. It is assumed that M <= N <= M+P, and */
/* rank(A) = M and rank( A B ) = N. */
/* Under these assumptions, the constrained equation is always */
/* consistent, and there is a unique solution x and a minimal 2-norm */
/* solution y, which is obtained using a generalized QR factorization */
/* of the matrices (A, B) given by */
/* A = Q*(R), B = Q*T*Z. */
/* (0) */
/* In particular, if matrix B is square nonsingular, then the problem */
/* GLM is equivalent to the following weighted linear least squares */
/* problem */
/* minimize || inv(B)*(d-A*x) ||_2 */
/* x */
/* where inv(B) denotes the inverse of B. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of rows of the matrices A and B. N >= 0. */
/* M (input) INTEGER */
/* The number of columns of the matrix A. 0 <= M <= N. */
/* P (input) INTEGER */
/* The number of columns of the matrix B. P >= N-M. */
/* A (input/output) REAL array, dimension (LDA,M) */
/* On entry, the N-by-M matrix A. */
/* On exit, the upper triangular part of the array A contains */
/* the M-by-M upper triangular matrix R. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* B (input/output) REAL array, dimension (LDB,P) */
/* On entry, the N-by-P matrix B. */
/* On exit, if N <= P, the upper triangle of the subarray */
/* B(1:N,P-N+1:P) contains the N-by-N upper triangular matrix T; */
/* if N > P, the elements on and above the (N-P)th subdiagonal */
/* contain the N-by-P upper trapezoidal matrix T. */
/* LDB (input) INTEGER */
/* The leading dimension of the array B. LDB >= max(1,N). */
/* D (input/output) REAL array, dimension (N) */
/* On entry, D is the left hand side of the GLM equation. */
/* On exit, D is destroyed. */
/* X (output) REAL array, dimension (M) */
/* Y (output) REAL array, dimension (P) */
/* On exit, X and Y are the solutions of the GLM problem. */
/* WORK (workspace/output) REAL array, dimension (MAX(1,LWORK)) */
/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
/* LWORK (input) INTEGER */
/* The dimension of the array WORK. LWORK >= max(1,N+M+P). */
/* For optimum performance, LWORK >= M+min(N,P)+max(N,P)*NB, */
/* where NB is an upper bound for the optimal blocksizes for */
/* SGEQRF, SGERQF, SORMQR and SORMRQ. */
/* If LWORK = -1, then a workspace query is assumed; the routine */
/* only calculates the optimal size of the WORK array, returns */
/* this value as the first entry of the WORK array, and no error */
/* message related to LWORK is issued by XERBLA. */
/* INFO (output) INTEGER */
/* = 0: successful exit. */
/* < 0: if INFO = -i, the i-th argument had an illegal value. */
/* = 1: the upper triangular factor R associated with A in the */
/* generalized QR factorization of the pair (A, B) is */
/* singular, so that rank(A) < M; the least squares */
/* solution could not be computed. */
/* = 2: the bottom (N-M) by (N-M) part of the upper trapezoidal */
/* factor T associated with B in the generalized QR */
/* factorization of the pair (A, B) is singular, so that */
/* rank( A B ) < N; the least squares solution could not */
/* be computed. */
/* =================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
b_dim1 = *ldb;
b_offset = 1 + b_dim1;
b -= b_offset;
--d__;
--x;
--y;
--work;
/* Function Body */
*info = 0;
np = min(*n,*p);
lquery = *lwork == -1;
if (*n < 0) {
*info = -1;
} else if (*m < 0 || *m > *n) {
*info = -2;
} else if (*p < 0 || *p < *n - *m) {
*info = -3;
} else if (*lda < max(1,*n)) {
*info = -5;
} else if (*ldb < max(1,*n)) {
*info = -7;
}
/* Calculate workspace */
if (*info == 0) {
if (*n == 0) {
lwkmin = 1;
lwkopt = 1;
} else {
nb1 = ilaenv_(&c__1, "SGEQRF", " ", n, m, &c_n1, &c_n1);
nb2 = ilaenv_(&c__1, "SGERQF", " ", n, m, &c_n1, &c_n1);
nb3 = ilaenv_(&c__1, "SORMQR", " ", n, m, p, &c_n1);
nb4 = ilaenv_(&c__1, "SORMRQ", " ", n, m, p, &c_n1);
/* Computing MAX */
i__1 = max(nb1,nb2), i__1 = max(i__1,nb3);
nb = max(i__1,nb4);
lwkmin = *m + *n + *p;
lwkopt = *m + np + max(*n,*p) * nb;
}
work[1] = (real) lwkopt;
if (*lwork < lwkmin && ! lquery) {
*info = -12;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SGGGLM", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
if (*n == 0) {
return 0;
}
/* Compute the GQR factorization of matrices A and B: */
/* Q'*A = ( R11 ) M, Q'*B*Z' = ( T11 T12 ) M */
/* ( 0 ) N-M ( 0 T22 ) N-M */
/* M M+P-N N-M */
/* where R11 and T22 are upper triangular, and Q and Z are */
/* orthogonal. */
i__1 = *lwork - *m - np;
sggqrf_(n, m, p, &a[a_offset], lda, &work[1], &b[b_offset], ldb, &work[*m
+ 1], &work[*m + np + 1], &i__1, info);
lopt = work[*m + np + 1];
/* Update left-hand-side vector d = Q'*d = ( d1 ) M */
/* ( d2 ) N-M */
i__1 = max(1,*n);
i__2 = *lwork - *m - np;
sormqr_("Left", "Transpose", n, &c__1, m, &a[a_offset], lda, &work[1], &
d__[1], &i__1, &work[*m + np + 1], &i__2, info);
/* Computing MAX */
i__1 = lopt, i__2 = (integer) work[*m + np + 1];
lopt = max(i__1,i__2);
/* Solve T22*y2 = d2 for y2 */
if (*n > *m) {
i__1 = *n - *m;
i__2 = *n - *m;
strtrs_("Upper", "No transpose", "Non unit", &i__1, &c__1, &b[*m + 1
+ (*m + *p - *n + 1) * b_dim1], ldb, &d__[*m + 1], &i__2,
info);
if (*info > 0) {
*info = 1;
return 0;
}
i__1 = *n - *m;
scopy_(&i__1, &d__[*m + 1], &c__1, &y[*m + *p - *n + 1], &c__1);
}
/* Set y1 = 0 */
i__1 = *m + *p - *n;
for (i__ = 1; i__ <= i__1; ++i__) {
y[i__] = 0.f;
/* L10: */
}
/* Update d1 = d1 - T12*y2 */
i__1 = *n - *m;
sgemv_("No transpose", m, &i__1, &c_b32, &b[(*m + *p - *n + 1) * b_dim1 +
1], ldb, &y[*m + *p - *n + 1], &c__1, &c_b34, &d__[1], &c__1);
/* Solve triangular system: R11*x = d1 */
if (*m > 0) {
strtrs_("Upper", "No Transpose", "Non unit", m, &c__1, &a[a_offset],
lda, &d__[1], m, info);
if (*info > 0) {
*info = 2;
return 0;
}
/* Copy D to X */
scopy_(m, &d__[1], &c__1, &x[1], &c__1);
}
/* Backward transformation y = Z'*y */
/* Computing MAX */
i__1 = 1, i__2 = *n - *p + 1;
i__3 = max(1,*p);
i__4 = *lwork - *m - np;
sormrq_("Left", "Transpose", p, &c__1, &np, &b[max(i__1, i__2)+ b_dim1],
ldb, &work[*m + 1], &y[1], &i__3, &work[*m + np + 1], &i__4, info);
/* Computing MAX */
i__1 = lopt, i__2 = (integer) work[*m + np + 1];
work[1] = (real) (*m + np + max(i__1,i__2));
return 0;
/* End of SGGGLM */
} /* sggglm_ */