# ggglm - Man Page

ggglm: Gauss-Markov linear model

## Synopsis

### Functions

subroutine cggglm (n, m, p, a, lda, b, ldb, d, x, y, work, lwork, info)
CGGGLM
subroutine dggglm (n, m, p, a, lda, b, ldb, d, x, y, work, lwork, info)
DGGGLM
subroutine sggglm (n, m, p, a, lda, b, ldb, d, x, y, work, lwork, info)
SGGGLM
subroutine zggglm (n, m, p, a, lda, b, ldb, d, x, y, work, lwork, info)
ZGGGLM

## Function Documentation

### subroutine cggglm (integer n, integer m, integer p, complex, dimension( lda, * ) a, integer lda, complex, dimension( ldb, * ) b, integer ldb, complex, dimension( * ) d, complex, dimension( * ) x, complex, dimension( * ) y, complex, dimension( * ) work, integer lwork, integer info)

CGGGLM

Purpose:

``` CGGGLM 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.```
Parameters

N

```          N is INTEGER
The number of rows of the matrices A and B.  N >= 0.```

M

```          M is INTEGER
The number of columns of the matrix A.  0 <= M <= N.```

P

```          P is INTEGER
The number of columns of the matrix B.  P >= N-M.```

A

```          A is COMPLEX 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

```          LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).```

B

```          B is COMPLEX 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

```          LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).```

D

```          D is COMPLEX array, dimension (N)
On entry, D is the left hand side of the GLM equation.
On exit, D is destroyed.```

X

`          X is COMPLEX array, dimension (M)`

Y

```          Y is COMPLEX array, dimension (P)

On exit, X and Y are the solutions of the GLM problem.```

WORK

```          WORK is COMPLEX array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.```

LWORK

```          LWORK is 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
CGEQRF, CGERQF, CUNMQR and CUNMRQ.

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

```          INFO is 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.```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 183 of file cggglm.f.

### subroutine dggglm (integer n, integer m, integer p, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) d, double precision, dimension( * ) x, double precision, dimension( * ) y, double precision, dimension( * ) work, integer lwork, integer info)

DGGGLM

Purpose:

``` DGGGLM 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.```
Parameters

N

```          N is INTEGER
The number of rows of the matrices A and B.  N >= 0.```

M

```          M is INTEGER
The number of columns of the matrix A.  0 <= M <= N.```

P

```          P is INTEGER
The number of columns of the matrix B.  P >= N-M.```

A

```          A is DOUBLE PRECISION 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

```          LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).```

B

```          B is DOUBLE PRECISION 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

```          LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).```

D

```          D is DOUBLE PRECISION array, dimension (N)
On entry, D is the left hand side of the GLM equation.
On exit, D is destroyed.```

X

`          X is DOUBLE PRECISION array, dimension (M)`

Y

```          Y is DOUBLE PRECISION array, dimension (P)

On exit, X and Y are the solutions of the GLM problem.```

WORK

```          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.```

LWORK

```          LWORK is 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
DGEQRF, SGERQF, DORMQR 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

```          INFO is 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.```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 183 of file dggglm.f.

### subroutine sggglm (integer n, integer m, integer p, real, dimension( lda, * ) a, integer lda, real, dimension( ldb, * ) b, integer ldb, real, dimension( * ) d, real, dimension( * ) x, real, dimension( * ) y, real, dimension( * ) work, integer lwork, integer info)

SGGGLM

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.```
Parameters

N

```          N is INTEGER
The number of rows of the matrices A and B.  N >= 0.```

M

```          M is INTEGER
The number of columns of the matrix A.  0 <= M <= N.```

P

```          P is INTEGER
The number of columns of the matrix B.  P >= N-M.```

A

```          A is 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

```          LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).```

B

```          B is 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

```          LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).```

D

```          D is REAL array, dimension (N)
On entry, D is the left hand side of the GLM equation.
On exit, D is destroyed.```

X

`          X is REAL array, dimension (M)`

Y

```          Y is REAL array, dimension (P)

On exit, X and Y are the solutions of the GLM problem.```

WORK

```          WORK is REAL array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.```

LWORK

```          LWORK is 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

```          INFO is 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.```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 183 of file sggglm.f.

### subroutine zggglm (integer n, integer m, integer p, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( ldb, * ) b, integer ldb, complex*16, dimension( * ) d, complex*16, dimension( * ) x, complex*16, dimension( * ) y, complex*16, dimension( * ) work, integer lwork, integer info)

ZGGGLM

Purpose:

``` ZGGGLM 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.```
Parameters

N

```          N is INTEGER
The number of rows of the matrices A and B.  N >= 0.```

M

```          M is INTEGER
The number of columns of the matrix A.  0 <= M <= N.```

P

```          P is INTEGER
The number of columns of the matrix B.  P >= N-M.```

A

```          A is COMPLEX*16 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

```          LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).```

B

```          B is COMPLEX*16 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

```          LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).```

D

```          D is COMPLEX*16 array, dimension (N)
On entry, D is the left hand side of the GLM equation.
On exit, D is destroyed.```

X

`          X is COMPLEX*16 array, dimension (M)`

Y

```          Y is COMPLEX*16 array, dimension (P)

On exit, X and Y are the solutions of the GLM problem.```

WORK

```          WORK is COMPLEX*16 array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.```

LWORK

```          LWORK is 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
ZGEQRF, ZGERQF, ZUNMQR and ZUNMRQ.

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

```          INFO is 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.```
Author

Univ. of Tennessee

Univ. of California Berkeley