naginterfaces.library.blas.zrotgs¶
- naginterfaces.library.blas.zrotgs(a, b)[source]¶
zrotgs
generates a complex Givens plane rotation having real sine.For full information please refer to the NAG Library document for f06cb
https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f06/f06cbf.html
- Parameters
- acomplex
The value , the first element of the vector which determines the rotation.
- bcomplex
The value , the second element of the vector which determines the rotation.
- Returns
- acomplex
The value .
- bcomplex
The value , the tangent of the rotation.
- ccomplex
The value , the cosine of the rotation.
- sfloat
The value , the sine of the rotation.
- Notes
No equivalent traditional C interface for this routine exists in the NAG Library.
zrotgs
generates a complex Givens plane rotation with parameters (complex) and (real), such that, given complex and :If is real, then is also real. On exit, is overwritten by , the tangent of the rotation; and can be reconstructed from the single stored value , by a subsequent call to
zcsgs()
.If and , where is the machine precision, the function sets and .
If and , the function sets
Note that is always set to , unless overflow would occur, in which case the function returns the value of the complex expression
is the float value given by .