#include "blaswrap.h"
/* csbmv.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"
/* Subroutine */ int csbmv_(char *uplo, integer *n, integer *k, complex *
alpha, complex *a, integer *lda, complex *x, integer *incx, complex *
beta, complex *y, integer *incy)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5;
complex q__1, q__2, q__3, q__4;
/* Local variables */
static integer i__, j, l, ix, iy, jx, jy, kx, ky, info;
static complex temp1, temp2;
extern logical lsame_(char *, char *);
static integer kplus1;
extern /* Subroutine */ int xerbla_(char *, integer *);
/* -- LAPACK auxiliary routine (version 3.1) --
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
Purpose
=======
CSBMV performs the matrix-vector operation
y := alpha*A*x + beta*y,
where alpha and beta are scalars, x and y are n element vectors and
A is an n by n symmetric band matrix, with k super-diagonals.
Arguments
==========
UPLO - CHARACTER*1
On entry, UPLO specifies whether the upper or lower
triangular part of the band matrix A is being supplied as
follows:
UPLO = 'U' or 'u' The upper triangular part of A is
being supplied.
UPLO = 'L' or 'l' The lower triangular part of A is
being supplied.
Unchanged on exit.
N - INTEGER
On entry, N specifies the order of the matrix A.
N must be at least zero.
Unchanged on exit.
K - INTEGER
On entry, K specifies the number of super-diagonals of the
matrix A. K must satisfy 0 .le. K.
Unchanged on exit.
ALPHA - COMPLEX
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
A - COMPLEX array, dimension( LDA, N )
Before entry with UPLO = 'U' or 'u', the leading ( k + 1 )
by n part of the array A must contain the upper triangular
band part of the symmetric matrix, supplied column by
column, with the leading diagonal of the matrix in row
( k + 1 ) of the array, the first super-diagonal starting at
position 2 in row k, and so on. The top left k by k triangle
of the array A is not referenced.
The following program segment will transfer the upper
triangular part of a symmetric band matrix from conventional
full matrix storage to band storage:
DO 20, J = 1, N
M = K + 1 - J
DO 10, I = MAX( 1, J - K ), J
A( M + I, J ) = matrix( I, J )
10 CONTINUE
20 CONTINUE
Before entry with UPLO = 'L' or 'l', the leading ( k + 1 )
by n part of the array A must contain the lower triangular
band part of the symmetric matrix, supplied column by
column, with the leading diagonal of the matrix in row 1 of
the array, the first sub-diagonal starting at position 1 in
row 2, and so on. The bottom right k by k triangle of the
array A is not referenced.
The following program segment will transfer the lower
triangular part of a symmetric band matrix from conventional
full matrix storage to band storage:
DO 20, J = 1, N
M = 1 - J
DO 10, I = J, MIN( N, J + K )
A( M + I, J ) = matrix( I, J )
10 CONTINUE
20 CONTINUE
Unchanged on exit.
LDA - INTEGER
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA must be at least
( k + 1 ).
Unchanged on exit.
X - COMPLEX array, dimension at least
( 1 + ( N - 1 )*abs( INCX ) ).
Before entry, the incremented array X must contain the
vector x.
Unchanged on exit.
INCX - INTEGER
On entry, INCX specifies the increment for the elements of
X. INCX must not be zero.
Unchanged on exit.
BETA - COMPLEX
On entry, BETA specifies the scalar beta.
Unchanged on exit.
Y - COMPLEX array, dimension at least
( 1 + ( N - 1 )*abs( INCY ) ).
Before entry, the incremented array Y must contain the
vector y. On exit, Y is overwritten by the updated vector y.
INCY - INTEGER
On entry, INCY specifies the increment for the elements of
Y. INCY must not be zero.
Unchanged on exit.
=====================================================================
Test the input parameters.
Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--x;
--y;
/* Function Body */
info = 0;
if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
info = 1;
} else if (*n < 0) {
info = 2;
} else if (*k < 0) {
info = 3;
} else if (*lda < *k + 1) {
info = 6;
} else if (*incx == 0) {
info = 8;
} else if (*incy == 0) {
info = 11;
}
if (info != 0) {
xerbla_("CSBMV ", &info);
return 0;
}
/* Quick return if possible. */
if (*n == 0 || alpha->r == 0.f && alpha->i == 0.f && (beta->r == 1.f &&
beta->i == 0.f)) {
return 0;
}
/* Set up the start points in X and Y. */
if (*incx > 0) {
kx = 1;
} else {
kx = 1 - (*n - 1) * *incx;
}
if (*incy > 0) {
ky = 1;
} else {
ky = 1 - (*n - 1) * *incy;
}
/* Start the operations. In this version the elements of the array A
are accessed sequentially with one pass through A.
First form y := beta*y. */
if (beta->r != 1.f || beta->i != 0.f) {
if (*incy == 1) {
if (beta->r == 0.f && beta->i == 0.f) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = i__;
y[i__2].r = 0.f, y[i__2].i = 0.f;
/* L10: */
}
} else {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = i__;
i__3 = i__;
q__1.r = beta->r * y[i__3].r - beta->i * y[i__3].i,
q__1.i = beta->r * y[i__3].i + beta->i * y[i__3]
.r;
y[i__2].r = q__1.r, y[i__2].i = q__1.i;
/* L20: */
}
}
} else {
iy = ky;
if (beta->r == 0.f && beta->i == 0.f) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = iy;
y[i__2].r = 0.f, y[i__2].i = 0.f;
iy += *incy;
/* L30: */
}
} else {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = iy;
i__3 = iy;
q__1.r = beta->r * y[i__3].r - beta->i * y[i__3].i,
q__1.i = beta->r * y[i__3].i + beta->i * y[i__3]
.r;
y[i__2].r = q__1.r, y[i__2].i = q__1.i;
iy += *incy;
/* L40: */
}
}
}
}
if (alpha->r == 0.f && alpha->i == 0.f) {
return 0;
}
if (lsame_(uplo, "U")) {
/* Form y when upper triangle of A is stored. */
kplus1 = *k + 1;
if (*incx == 1 && *incy == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = j;
q__1.r = alpha->r * x[i__2].r - alpha->i * x[i__2].i, q__1.i =
alpha->r * x[i__2].i + alpha->i * x[i__2].r;
temp1.r = q__1.r, temp1.i = q__1.i;
temp2.r = 0.f, temp2.i = 0.f;
l = kplus1 - j;
/* Computing MAX */
i__2 = 1, i__3 = j - *k;
i__4 = j - 1;
for (i__ = max(i__2,i__3); i__ <= i__4; ++i__) {
i__2 = i__;
i__3 = i__;
i__5 = l + i__ + j * a_dim1;
q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i,
q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5]
.r;
q__1.r = y[i__3].r + q__2.r, q__1.i = y[i__3].i + q__2.i;
y[i__2].r = q__1.r, y[i__2].i = q__1.i;
i__2 = l + i__ + j * a_dim1;
i__3 = i__;
q__2.r = a[i__2].r * x[i__3].r - a[i__2].i * x[i__3].i,
q__2.i = a[i__2].r * x[i__3].i + a[i__2].i * x[
i__3].r;
q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i;
temp2.r = q__1.r, temp2.i = q__1.i;
/* L50: */
}
i__4 = j;
i__2 = j;
i__3 = kplus1 + j * a_dim1;
q__3.r = temp1.r * a[i__3].r - temp1.i * a[i__3].i, q__3.i =
temp1.r * a[i__3].i + temp1.i * a[i__3].r;
q__2.r = y[i__2].r + q__3.r, q__2.i = y[i__2].i + q__3.i;
q__4.r = alpha->r * temp2.r - alpha->i * temp2.i, q__4.i =
alpha->r * temp2.i + alpha->i * temp2.r;
q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i;
y[i__4].r = q__1.r, y[i__4].i = q__1.i;
/* L60: */
}
} else {
jx = kx;
jy = ky;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__4 = jx;
q__1.r = alpha->r * x[i__4].r - alpha->i * x[i__4].i, q__1.i =
alpha->r * x[i__4].i + alpha->i * x[i__4].r;
temp1.r = q__1.r, temp1.i = q__1.i;
temp2.r = 0.f, temp2.i = 0.f;
ix = kx;
iy = ky;
l = kplus1 - j;
/* Computing MAX */
i__4 = 1, i__2 = j - *k;
i__3 = j - 1;
for (i__ = max(i__4,i__2); i__ <= i__3; ++i__) {
i__4 = iy;
i__2 = iy;
i__5 = l + i__ + j * a_dim1;
q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i,
q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5]
.r;
q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i;
y[i__4].r = q__1.r, y[i__4].i = q__1.i;
i__4 = l + i__ + j * a_dim1;
i__2 = ix;
q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i,
q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[
i__2].r;
q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i;
temp2.r = q__1.r, temp2.i = q__1.i;
ix += *incx;
iy += *incy;
/* L70: */
}
i__3 = jy;
i__4 = jy;
i__2 = kplus1 + j * a_dim1;
q__3.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__3.i =
temp1.r * a[i__2].i + temp1.i * a[i__2].r;
q__2.r = y[i__4].r + q__3.r, q__2.i = y[i__4].i + q__3.i;
q__4.r = alpha->r * temp2.r - alpha->i * temp2.i, q__4.i =
alpha->r * temp2.i + alpha->i * temp2.r;
q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i;
y[i__3].r = q__1.r, y[i__3].i = q__1.i;
jx += *incx;
jy += *incy;
if (j > *k) {
kx += *incx;
ky += *incy;
}
/* L80: */
}
}
} else {
/* Form y when lower triangle of A is stored. */
if (*incx == 1 && *incy == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__3 = j;
q__1.r = alpha->r * x[i__3].r - alpha->i * x[i__3].i, q__1.i =
alpha->r * x[i__3].i + alpha->i * x[i__3].r;
temp1.r = q__1.r, temp1.i = q__1.i;
temp2.r = 0.f, temp2.i = 0.f;
i__3 = j;
i__4 = j;
i__2 = j * a_dim1 + 1;
q__2.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__2.i =
temp1.r * a[i__2].i + temp1.i * a[i__2].r;
q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i;
y[i__3].r = q__1.r, y[i__3].i = q__1.i;
l = 1 - j;
/* Computing MIN */
i__4 = *n, i__2 = j + *k;
i__3 = min(i__4,i__2);
for (i__ = j + 1; i__ <= i__3; ++i__) {
i__4 = i__;
i__2 = i__;
i__5 = l + i__ + j * a_dim1;
q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i,
q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5]
.r;
q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i;
y[i__4].r = q__1.r, y[i__4].i = q__1.i;
i__4 = l + i__ + j * a_dim1;
i__2 = i__;
q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i,
q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[
i__2].r;
q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i;
temp2.r = q__1.r, temp2.i = q__1.i;
/* L90: */
}
i__3 = j;
i__4 = j;
q__2.r = alpha->r * temp2.r - alpha->i * temp2.i, q__2.i =
alpha->r * temp2.i + alpha->i * temp2.r;
q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i;
y[i__3].r = q__1.r, y[i__3].i = q__1.i;
/* L100: */
}
} else {
jx = kx;
jy = ky;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__3 = jx;
q__1.r = alpha->r * x[i__3].r - alpha->i * x[i__3].i, q__1.i =
alpha->r * x[i__3].i + alpha->i * x[i__3].r;
temp1.r = q__1.r, temp1.i = q__1.i;
temp2.r = 0.f, temp2.i = 0.f;
i__3 = jy;
i__4 = jy;
i__2 = j * a_dim1 + 1;
q__2.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__2.i =
temp1.r * a[i__2].i + temp1.i * a[i__2].r;
q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i;
y[i__3].r = q__1.r, y[i__3].i = q__1.i;
l = 1 - j;
ix = jx;
iy = jy;
/* Computing MIN */
i__4 = *n, i__2 = j + *k;
i__3 = min(i__4,i__2);
for (i__ = j + 1; i__ <= i__3; ++i__) {
ix += *incx;
iy += *incy;
i__4 = iy;
i__2 = iy;
i__5 = l + i__ + j * a_dim1;
q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i,
q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5]
.r;
q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i;
y[i__4].r = q__1.r, y[i__4].i = q__1.i;
i__4 = l + i__ + j * a_dim1;
i__2 = ix;
q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i,
q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[
i__2].r;
q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i;
temp2.r = q__1.r, temp2.i = q__1.i;
/* L110: */
}
i__3 = jy;
i__4 = jy;
q__2.r = alpha->r * temp2.r - alpha->i * temp2.i, q__2.i =
alpha->r * temp2.i + alpha->i * temp2.r;
q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i;
y[i__3].r = q__1.r, y[i__3].i = q__1.i;
jx += *incx;
jy += *incy;
/* L120: */
}
}
}
return 0;
/* End of CSBMV */
} /* csbmv_ */