FLA_Bidiag_UT_internal.c File Reference

(r)

Functions
FLA_Error	FLA_Bidiag_UT_internal (FLA_Obj A, FLA_Obj TU, FLA_Obj TV, fla_bidiagut_t *cntl)

---

Function Documentation

FLA_Error FLA_Bidiag_UT_internal	(	FLA_Obj	A,
		FLA_Obj	TU,
		FLA_Obj	TV,
		fla_bidiagut_t *	cntl
	)

References FLA_Bidiag_UT_internal_check(), FLA_Bidiag_UT_u(), FLA_Check_error_level(), FLA_Conjugate(), FLA_Conjugate_r(), FLA_Obj_flip_base(), FLA_Obj_flip_view(), FLA_Obj_is_complex(), FLA_Obj_length(), FLA_Obj_width(), FLA_Part_1x2(), and FLA_Part_2x2().

Referenced by FLA_Bidiag_UT().

{
    FLA_Error r_val = FLA_SUCCESS;
    
    if ( FLA_Check_error_level() == FLA_FULL_ERROR_CHECKING )
        FLA_Bidiag_UT_internal_check( A, TU, TV, cntl );

    if ( FLA_Obj_length( A ) >= FLA_Obj_width( A ) )
    {
          r_val = FLA_Bidiag_UT_u( A, TU, TV, cntl );
    }
    else // if ( FLA_Obj_length( A ) < FLA_Obj_width( A ) )
    {
          // Flip A; swap(rs, cs), swap(m, n)
          FLA_Obj_flip_base( &A );
          FLA_Obj_flip_view( &A );
          
          r_val = FLA_Bidiag_UT_u( A, TV, TU, cntl );

          // Recover A; swap(rs, cs), swap(m, n)
          FLA_Obj_flip_base( &A );
          FLA_Obj_flip_view( &A );

          // According to the UT transform, the house-holder vectors are conjugated 
          // when they are applied from the right. 
          if ( FLA_Obj_is_complex( A ) ) 
          {
            FLA_Obj ATL, ATR,
                    ABL, ABR;
            dim_t   b;

            FLA_Conjugate( TU );
            FLA_Conjugate( TV );

            // U
            b = ( FLA_Obj_length( A ) - 1 );
            FLA_Part_2x2( A,    &ATL, &ATR,
                                &ABL, &ABR,    2, b, FLA_TL );
            FLA_Conjugate_r( FLA_LOWER_TRIANGULAR, ABL );
            
            // V
            b = ( FLA_Obj_width( A ) - 1 );
            FLA_Part_1x2( A,    &ATL, &ATR,    b, FLA_RIGHT );
            FLA_Conjugate_r( FLA_UPPER_TRIANGULAR, ATR );
          }
        }

    return r_val;
}