dcabs1 dzasum dznrm2 zaxpy zcopy zdotc zdotc_sub zdotu zdotu_sub zdrot zdscal zrot zrotg zscal zswap

zrotg() void zrotg ( doublecomplex *  za, doublecomplex *  zb, double *  c, doublecomplex *  zs  ) Constructs Givens plane rotation (complex vector) (BLAS 1) Purpose This routine constructs Givens plane rotation for the point (a, b) as below. ( c s ) * ( a ) = ( r ) (-conjg(s) c ) ( b ) ( 0 ) where r = (a/sqrt(conjg(a)*a))*sqrt(conjg(a)*a + conjg(b)*b), if |a| != 0, r = b, if |a| = 0. The constructed plane rotation can be used by zrot to convert the points to the new coordinate system. Parameters [in,out] za [in] a value [out] r value [in] zb b value. [out] c c (cosine) value. [out] zs s (sine) value. Reference BLAS