- naginterfaces.library.blas.drotgc(a, b)¶
drotgcgenerates a real Givens plane rotation and the tangent of that rotation.
For full information please refer to the NAG Library document for f06ba
The value , the first element of the vector which determines the rotation.
The value , the second element of the vector which determines the rotation.
The value .
The value , the tangent of the rotation.
The value , the cosine of the rotation.
The value , the sine of the rotation.
No equivalent traditional C interface for this routine exists in the NAG Library.
drotgcgenerates a real Givens plane rotation with parameters () and , such that, given real and :
On exit, is overwritten by , the tangent of the rotation; and can be reconstructed from the single stored value , by a subsequent call to
If , where is the machine precision, the function sets and ; if , the function sets and .
Note that is always set to , unless this would overflow, in which case the value is returned, where is the value given by .