Dsyr2.java
package org.mklab.sdpj.gpack.blaswrap;
import org.mklab.nfc.matrix.ComplexNumericalMatrix;
import org.mklab.nfc.matrix.RealNumericalMatrix;
import org.mklab.nfc.scalar.ComplexNumericalScalar;
import org.mklab.nfc.scalar.RealNumericalScalar;
/**
* @author koga
* @version $Revision$, 2009/04/24
* @param <RS> 実スカラーの型
* @param <RM> 実行列の型
* @param <CS> 複素スカラーの型
* @param <CM> 複素行列の型
*/
public class Dsyr2<RS extends RealNumericalScalar<RS, RM, CS, CM>, RM extends RealNumericalMatrix<RS, RM, CS, CM>, CS extends ComplexNumericalScalar<RS, RM, CS, CM>, CM extends ComplexNumericalMatrix<RS, RM, CS, CM>> {
/* Purpose
=======
DSYR2 performs the symmetric rank 2 operation
A := alpha*x*y' + alpha*y*x' + A,
where alpha is a scalar, x and y are n element vectors and A is an n
by n symmetric matrix.
Parameters
==========
UPLO - CHARACTER*1.
On entry, UPLO specifies whether the upper or lower
triangular part of the array A is to be referenced as
follows:
UPLO = 'U' or 'u' Only the upper triangular part of A
is to be referenced.
UPLO = 'L' or 'l' Only the lower triangular part of A
is to be referenced.
Unchanged on exit.
N - INTEGER.
On entry, N specifies the order of the matrix A.
N must be at least zero.
Unchanged on exit.
ALPHA - DOUBLE PRECISION.
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
X - DOUBLE PRECISION array of dimension at least
( 1 + ( n - 1 )*abs( INCX ) ).
Before entry, the incremented array X must contain the n
element 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.
Y - DOUBLE PRECISION array of dimension at least
( 1 + ( n - 1 )*abs( INCY ) ).
Before entry, the incremented array Y must contain the n
element vector y.
Unchanged on exit.
INCY - INTEGER.
On entry, INCY specifies the increment for the elements of
Y. INCY must not be zero.
Unchanged on exit.
A - DOUBLE PRECISION array of DIMENSION ( LDA, n ).
Before entry with UPLO = 'U' or 'u', the leading n by n
upper triangular part of the array A must contain the upper
triangular part of the symmetric matrix and the strictly
lower triangular part of A is not referenced. On exit, the
upper triangular part of the array A is overwritten by the
upper triangular part of the updated matrix.
Before entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array A must contain the lower
triangular part of the symmetric matrix and the strictly
upper triangular part of A is not referenced. On exit, the
lower triangular part of the array A is overwritten by the
lower triangular part of the updated matrix.
LDA - INTEGER.
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA must be at least
max( 1, n ).
Unchanged on exit.
Level 2 Blas routine.
-- Written on 22-October-1986.
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.
Test the input parameters.
Parameter adjustments */
/**
* @param uplo uplo
* @param n n
* @param alpha alpha
* @param x x
* @param incx incx
* @param y y
* @param incy incy
* @param a a
* @param lda lda
* @return result
*/
int execute(String uplo, int n, RS alpha, RS[] x, int incx, RS[] y, int incy, RS[] a, int lda) {
int a_dim1 = lda;
int a_offset = 1 + a_dim1 * 1;
int pointer_a = -a_offset;
int info = 0;
if (!BLAS.lsame(uplo, "U") && !BLAS.lsame(uplo, "L")) { //$NON-NLS-1$ //$NON-NLS-2$
info = 1;
} else if (n < 0) {
info = 2;
} else if (incx == 0) {
info = 5;
} else if (incy == 0) {
info = 7;
} else if (lda < Math.max(1, n)) {
info = 9;
}
if (info != 0) {
BLAS.xerbla("DSYR2 ", info); //$NON-NLS-1$
return 0;
}
// Quick return if possible.
if (n == 0 || alpha.isZero()) {
return 0;
}
// Set up the start points in X and Y if the increments are not both unity.
int kx = 0;
int ky = 0;
int jx = 0;
int jy = 0;
if (incx != 1 || incy != 1) {
if (incx > 0) {
kx = 1;
} else {
kx = 1 - (n - 1) * incx;
}
if (incy > 0) {
ky = 1;
} else {
ky = 1 - (n - 1) * incy;
}
jx = kx;
jy = ky;
}
/* Start the operations. In this version the elements of A are
* accessed sequentially with one pass through the triangular part of A.
*/
if (BLAS.lsame(uplo, "U")) { //$NON-NLS-1$
// Form A when A is stored in the upper triangle.
if (incx == 1 && incy == 1) {
for (int j = 1; j <= n; ++j) {
if (!x[j - 1].isZero() || !y[j - 1].isZero()) {
RS temp1 = alpha.multiply(y[j - 1]);
RS temp2 = alpha.multiply(x[j - 1]);
for (int i = 1; i <= j; ++i) {
int p = j * a_dim1 + i + pointer_a;
a[p] = a[p].add(x[i - 1].multiply(temp1)).add(y[i - 1].multiply(temp2));
}
}
}
} else {
for (int j = 1; j <= n; ++j) {
if (!x[jx - 1].isZero() || !y[jy - 1].isZero()) {
RS temp1 = alpha.multiply(y[jy - 1]);
RS temp2 = alpha.multiply(x[jx - 1]);
int ix = kx;
int iy = ky;
for (int i = 1; i <= j; ++i) {
int p = j * a_dim1 + i + pointer_a;
a[p] = a[p].add(x[ix - 1].multiply(temp1)).add(y[iy - 1].multiply(temp2));
ix += incx;
iy += incy;
}
}
jx += incx;
jy += incy;
}
}
} else {
// Form A when A is stored in the lower triangle.
if (incx == 1 && incy == 1) {
for (int j = 1; j <= n; ++j) {
if (!x[j - 1].isZero() || !y[j - 1].isZero()) {
RS temp1 = alpha.multiply(y[j - 1]);
RS temp2 = alpha.multiply(x[j - 1]);
for (int i = j; i <= n; ++i) {
int p = j * a_dim1 + i + pointer_a;
a[p] = a[p].add(x[i - 1].multiply(temp1)).add(y[i - 1].multiply(temp2));
}
}
}
} else {
for (int j = 1; j <= n; ++j) {
if (!x[jx - 1].isZero() || !y[jy - 1].isZero()) {
RS temp1 = alpha.multiply(y[jy - 1]);
RS temp2 = alpha.multiply(x[jx - 1]);
int ix = jx;
int iy = jy;
for (int i = j; i <= n; ++i) {
int p = j * a_dim1 + i + pointer_a;
a[p] = a[p].add(x[ix - 1].multiply(temp1)).add(y[iy - 1].multiply(temp2));
ix += incx;
iy += incy;
}
}
jx += incx;
jy += incy;
}
}
}
return 0;
}
}