Function

# cblas_zrotg

Constructs a complex Givens rotation.

## Parameters

a

Complex value a. Overwritten on return with result r.

b

Complex value a. Overwritten on return with result z (zero).

c

Real value c. Unused on entry. Overwritten on return with the value cos(θ).

s

Complex value s. Unused on entry. Overwritten on return with the value sin(θ).

## Discussion

Given a vertical matrix containing a and b, computes the values of cos θ and sin θ that zero the lower value (b). Returns the value of sin θ in s, the value of cos θ in c, and the upper value (r) in a.

### Double-Precision Complex Matrix Functions

cblas_dzasum

Computes the sum of the absolute values of real and imaginary parts of elements in a vector (single-precision complex).

cblas_dznrm2

Computes the unitary norm of a vector (double-precision complex).

cblas_zaxpy

Computes a constant times a vector plus a vector (double-precision complex).

cblas_zcopy

Copies a vector to another vector (double-precision complex).

cblas_zdrot

Applies a Givens rotation matrix to a pair of complex vectors.

cblas_zdscal

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

cblas_zgbmv

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

cblas_zgemm

Multiplies two matrices (double-precision complex).

cblas_zgemv

Multiplies a matrix by a vector (double-precision complex).

cblas_zgerc

Multiplies vector X by the conjugate transpose of vector Y, then adds matrix A (double-precision complex).

cblas_zgeru

Multiplies vector X by the transpose of vector Y, then adds matrix A (double-precision complex).

cblas_zhbmv

Scales a Hermitian band matrix, then multiplies by a vector, then adds a vector (double-precision complex).

cblas_zhemm

Multiplies two Hermitian matrices (double-precision complex).

cblas_zhemv

Scales and multiplies a Hermitian matrix by a vector, then adds a second (scaled) vector.

cblas_zher

Adds the product of a scaling factor, vector X, and the conjugate transpose of X to matrix A.

cblas_zher2

Hermitian rank 2 update: adds the product of a scaling factor, vector X, and the conjugate transpose of vector Y to the product of the conjugate of the scaling factor, vector Y, and the conjugate transpose of vector X, and adds the result to matrix A.

cblas_zher2k

Performs a rank-2k update of a complex Hermitian matrix (double-precision complex).

cblas_zherk

Rank-k update—multiplies a Hermitian matrix by its transpose and adds a second matrix (single precision).

cblas_zhpmv

Scales a packed hermitian matrix, multiplies it by a vector, and adds a scaled vector.

cblas_zhpr

Scales and multiplies a vector times its conjugate transpose, then adds a matrix.

cblas_zhpr2

Multiplies a vector times the conjugate transpose of a second vector and vice-versa, sums the results, and adds a matrix.

cblas_zscal

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

cblas_zswap

Exchanges the elements of two vectors (double-precision complex).

cblas_zsymm

Multiplies a matrix by a symmetric matrix (double-precision complex).

cblas_zsyr2k

Performs a rank-2k update of a symmetric matrix (double-precision complex).

cblas_zsyrk

Rank-k update—multiplies a symmetric matrix by its transpose and adds a second matrix (double-precision complex).

cblas_ztbmv

Scales a triangular band matrix, then multiplies by a vector (double-precision complex).

cblas_ztbsv

Solves a triangular banded system of equations.

cblas_ztpmv

Multiplies a triangular matrix by a vector, then adds a vector (double-precision compex).

cblas_ztpsv

Solves a packed triangular system of equations.

cblas_ztrmm

Scales a triangular matrix and multiplies it by a matrix.

cblas_ztrmv

Multiplies a triangular matrix by a vector.

cblas_ztrsm

Solves a triangular system of equations with multiple values for the right side.

cblas_ztrsv

Solves a triangular system of equations with a single value for the right side.