Function

cblas_crotg

Constructs a complex Givens rotation.

Declaration

void cblas_crotg(void *__a, void *__b, void *__c, void *__s);

Parameters

a: Complex value a. Overwritten on output.
b: Complex value a.
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.

See Also

Single-Precision Complex Matrix Functions

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

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

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

Multiplies two matrices (single-precision complex).

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

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

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

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

Multiplies two Hermitian matrices (single-precision complex), then adds a third (with scaling).

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

Hermitian rank 1 update: adds the product of a scaling factor, vector X, and the conjugate transpose of X to matrix A.

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.

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

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

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

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

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

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

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

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

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

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

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

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

Scales a triangular band matrix, then multiplies by a vector (single-precision compex).

Solves a triangular banded system of equations.

Multiplies a triangular matrix by a vector, then adds a vector (single-precision complex).

Solves a packed triangular system of equations.

Scales a triangular matrix and multiplies it by a matrix.

Multiplies a triangular matrix by a vector.

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

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

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

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