(S|D)SPR2¶

Single and double SPR2.

Description¶

Computes the symmetric packed rank-2 operation:

$A \assign \alpha x * \trans{y} + \alpha y * \trans{x} + A$

BLAS Interface¶

void sspr2(const char *UPLO, const qml_long *N, const float *ALPHA,
           const float *X, const qml_long *INCX, const float *Y,
           const qml_long *INCY, float *AP);

void dspr2(const char *UPLO, const qml_long *N, const double *ALPHA,
           const double *X, const qml_long *INCX, const double *Y,
           const qml_long *INCY, double *AP);

CBLAS Interface¶

void cblas_sspr2(const CBLAS_ORDER ORDER, const CBLAS_UPLO UPLO, const qml_long N,
                 const float ALPHA, const float *X, const qml_long INCX,
                 const float *Y, const qml_long INCY, float *AP);

void cblas_dspr2(const CBLAS_ORDER ORDER, const CBLAS_UPLO UPLO, const qml_long N,
                 const double ALPHA, const double *X, const qml_long INCX,
                 const double *Y, const qml_long INCY, double *AP);

Arguments¶

UPLO	Specify whether the upper or lower triangle of matrix A will be used
N	Order of matrix A
ALPHA	Scalar multiplied with the vector-vector product
X	First input vector, must be at least: $(\fvar{N}-1)\mult\abs{\fvar{INCX}} + 1$
INCX	Distance between individual elements in X
Y	Second input vector, must be at least: $(\fvar{N}-1)\mult\abs{\fvar{INCY}} + 1$
INCY	Distance between individual elements in Y
AP	Matrix A stored in packed triangular form, must be at least: $\fvar{N}\mult(\fvar{N}+1)/2$