Developer Reference for Intel® oneAPI Math Kernel Library for C
?lartgp
Generates a plane rotation.
Syntax
lapack_intLAPACKE_slartgp ( floatf , floatg , float*cs , float*sn , float*r );
lapack_intLAPACKE_dlartgp ( doublef , doubleg , double*cs , double*sn , double*r );
Include Files
mkl.h
Description
The routine generates a plane rotation so that
where cs^{2} + sn^{2} = 1
This is a slower, more accurate version of the BLAS Level 1 routine ?rotg , except for the following differences:
f and g are unchanged on return.
If g =0, then cs =(+/-)1 and sn =0.
If f =0 and g ≠ 0, then cs =0 and sn =(+/-)1.
The sign is chosen so that r ≥ 0.
Input Parameters
A <datatype> placeholder, if present, is used for the C interface data types in the C interface section above. See C Interface Conventions for the C interface principal conventions and type definitions.
- f , g
-
REAL for slartgp DOUBLE PRECISION for dlartgp The first and second component of the vector to be rotated.
Output Parameters
- cs
-
REAL for slartgp DOUBLE PRECISION for dlartgp The cosine of the rotation.
- sn
-
REAL for slartgp DOUBLE PRECISION for dlartgp The sine of the rotation.
- r
-
REAL for slartgp DOUBLE PRECISION for dlartgp The nonzero component of the rotated vector.
Return Values
If info = 0 , the execution is successful.
If info =-1 , f is NaN.
If info = -2 , g is NaN.