(S|D)SPMV
=============
Single and double SPMV.

Description
-----------
Computes the symmetric packed matrix-vector operation: 

.. math::

    y \assign \alpha A * x + \beta y

BLAS Interface
--------------
.. code-block:: c

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

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


CBLAS Interface
---------------
.. code-block:: c

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

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


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 matrix-vector product
AP       Matrix A stored in packed triangular form, must be at least: :math:`\fvar{N}\mult(\fvar{N}+1)/2`
ALPHA    Scalar multiplied with the matrix-vector product
X        First input vector, must be at least: :math:`(\fvar{N}-1)\mult\abs{\fvar{INCX}} + 1`
INCX     Distance between individual elements in X
BETA     Scalar multiplied with vector Y
Y        Second vector, must be at least: :math:`(\fvar{M}-1)\mult\abs{\fvar{INCY}} + 1`
INCY     Distance between individual elements in Y
======   =====================================================================
