rocblas_srotg Interface Reference#
hipfort_rocblas::rocblas_srotg Interface Reference
BLAS Level 1 API. More...
Public Member Functions | |
| integer(kind(rocblas_status_success)) function | rocblas_srotg_ (handle, a, b, c, s) |
Detailed Description
BLAS Level 1 API.
The rotg functions create the Givens rotation matrix for the vector (a b). Scalars a, b, c, and s can be stored in either host or device memory. The location is specified by calling rocblas_set_pointer_mode. The computation uses the formulas:
sigma = sgn(a) if |a| > |b|
= sgn(b) if |b| >= |a|
r = sigma*sqrt( a**2 + b**2 )
c = 1; s = 0 if r = 0
c = a/r; s = b/r if r != 0
The subroutine also computes:
z = s if |a| > |b|, = 1/c if |b| >= |a| and c != 0 = 1 if c = 0
This allows c and s to be reconstructed from z as follows:
If z = 1, set c = 0, s = 1. If |z| < 1, set c = sqrt(1 - z**2) and s = z. If |z| > 1, set c = 1/z and s = sqrt( 1 - c**2).
- Parameters
-
[in] handle - [rocblas_handle] handle to the rocBLAS library context queue. [in,out] a - pointer to a, an element in vector (a,b), overwritten with r. [in,out] b - pointer to b, an element in vector (a,b), overwritten with z. [out] c - pointer to c, cosine element of the Givens rotation. [out] s - pointer to s, sine element of the Givens rotation.
Member Function/Subroutine Documentation
◆ rocblas_srotg_()
| integer(kind(rocblas_status_success)) function hipfort_rocblas::rocblas_srotg::rocblas_srotg_ | ( | type(c_ptr), value | handle, |
| type(c_ptr), value | a, | ||
| type(c_ptr), value | b, | ||
| type(c_ptr), value | c, | ||
| type(c_ptr), value | s | ||
| ) |
The documentation for this interface was generated from the following file: