Function

# cblas_dgbmv(_:_:_:_:_:_:_:_:_:_:_:_:_:_:)

Scales a general band matrix, then multiplies by a vector, then adds a vector (double precision).

## Parameters

`Order`

Specifies row-major (C) or column-major (Fortran) data ordering.

`TransA`

Specifies whether to use matrix A (`'N'` or `'n'`) or the transpose of A (`'T'`, `'t'`, `'C'`, or `'c'`).

`M`

Number of rows in matrix A.

`N`

Number of columns in matrix A.

`KL`

Number of subdiagonals in matrix A.

`KU`

Number of superdiagonals in matrix A.

`alpha`

Scaling factor to multiply matrix `A` by.

`A`

Matrix `A`.

`lda`

Leading dimension of array containing matrix `A`. (Must be at least `KL+KU+1`.)

`X`

Vector `X`.

`incX`

Stride within `X`. For example, if `incX` is 7, every 7th element is used.

`beta`

Scaling factor to multiply vector Y by.

`Y`

Vector Y.

`incY`

Stride within `Y`. For example, if `incY` is 7, every 7th element is used.

## Discussion

Computes `alpha*A*x + beta*y` or `alpha*A'*x + beta*y` depending on the value of `TransA`.

### Double-Precision Float Matrix Functions

`func cblas_dasum(Int32, UnsafePointer<Double>!, Int32) -> Double`

Computes the sum of the absolute values of elements in a vector (double-precision).

`func cblas_dnrm2(Int32, UnsafePointer<Double>!, Int32) -> Double`

Computes the L2 norm (Euclidian length) of a vector (double precision).

`func cblas_dscal(Int32, Double, UnsafeMutablePointer<Double>!, Int32)`

Multiplies each element of a vector by a constant (double-precision).

`func cblas_dspmv(CBLAS_ORDER, CBLAS_UPLO, Int32, Double, UnsafePointer<Double>!, UnsafePointer<Double>!, Int32, Double, UnsafeMutablePointer<Double>!, Int32)`

Scales a packed symmetric matrix, then multiplies by a vector, then scales and adds another vector (double precision).

`func cblas_dspr(CBLAS_ORDER, CBLAS_UPLO, Int32, Double, UnsafePointer<Double>!, Int32, UnsafeMutablePointer<Double>!)`

Rank one update: adds a packed symmetric matrix to the product of a scaling factor, a vector, and its transpose (double precision).

`func cblas_dsyr(CBLAS_ORDER, CBLAS_UPLO, Int32, Double, UnsafePointer<Double>!, Int32, UnsafeMutablePointer<Double>!, Int32)`

Rank one update: adds a symmetric matrix to the product of a scaling factor, a vector, and its transpose (double precision).