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CXXBLAS Level 1: axpy

axpy (defined in namespace cxxblas) computes \(y \leftarrow y +\alpha x\) where \(x, y\) are vectors and \(\alpha\) is a constant scalar.

Generic Implementation

template <typename IndexType, typename ALPHA, typename X, typename Y>
    void
    axpy(IndexType n, const ALPHA &alpha, const X *x, IndexType incX,
         Y *y, IndexType incY);

n

(input)
Specifies the number of elements in vector \(x\) and \(y\).

alpha

(input)
Scaling factor for the values in \(x\).

x

(input)
Pointer to the first element of vector \(x\).

incX

(input)
Specifies the increment for indexing vector \(x\).

y

(input/output)
Pointer to the first element of vector \(y\).

incY

(input)
Specifies the increment for indexing vector \(y\).

CBLAS Implementation

If a CBLAS implementations like ATLAS, GotoBLAS, ... is available then the following optimized variants are provided.

Single Precision

template <typename IndexType>
    typename If<IndexType>::isBlasCompatibleInteger
    axpy(IndexType n, const float &alpha,
         const float *x, IndexType incX,
         float *y, IndexType incY);

Double Precision

template <typename IndexType>
    typename If<IndexType>::isBlasCompatibleInteger
    axpy(IndexType n, const double &alpha,
         const double *x, IndexType incX,
         double *y, IndexType incY);

Complex Single Precision

template <typename IndexType>
    typename If<IndexType>::isBlasCompatibleInteger
    axpy(IndexType n, const ComplexFloat &alpha,
         const ComplexFloat *x, IndexType incX,
         ComplexFloat *y, IndexType incY);

Complex Double Precision

template <typename IndexType>
    typename If<IndexType>::isBlasCompatibleInteger
    axpy(IndexType n, const ComplexDouble &alpha,
         const ComplexDouble *x, IndexType incX,
         ComplexDouble *y, IndexType incY);
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