FLA_LU_nopiv_unb_var1.c File Reference

(r)

Functions
FLA_Error	FLA_LU_nopiv_unb_var1 (FLA_Obj A)

---

Function Documentation

FLA_Error FLA_LU_nopiv_unb_var1

(

FLA_Obj

A

)

References FLA_Cont_with_3x3_to_2x2(), FLA_Dots_external(), FLA_MINUS_ONE, FLA_Obj_length(), FLA_Obj_width(), FLA_ONE, FLA_Part_2x2(), FLA_Repart_2x2_to_3x3(), FLA_Trsm_external(), and FLA_Trsv_external().

Referenced by FLA_LU_nopiv_internal().

{
  FLA_Obj ATL,   ATR,      A00,  a01,     A02, 
          ABL,   ABR,      a10t, alpha11, a12t,
                           A20,  a21,     A22;

  FLA_Part_2x2( A,    &ATL, &ATR,
                      &ABL, &ABR,     0, 0, FLA_TL );

  while ( FLA_Obj_length( ATL ) < FLA_Obj_length( A ) &&
          FLA_Obj_width( ATL ) < FLA_Obj_width( A )){

    FLA_Repart_2x2_to_3x3( ATL, /**/ ATR,       &A00,  /**/ &a01,     &A02,
                        /* ************* */   /* ************************** */
                                                &a10t, /**/ &alpha11, &a12t,
                           ABL, /**/ ABR,       &A20,  /**/ &a21,     &A22,
                           1, 1, FLA_BR );

    /*------------------------------------------------------------*/

    // a01 = trilu( A00 ) \ a01
    FLA_Trsv_external( FLA_LOWER_TRIANGULAR, FLA_NO_TRANSPOSE, FLA_UNIT_DIAG, A00, a01 );

    // a10t = a10t / triu( A00 )
    FLA_Trsv_external( FLA_UPPER_TRIANGULAR, FLA_TRANSPOSE, FLA_NONUNIT_DIAG, A00, a10t );

    // alpha11 = alpha11 - a10t * a01
    FLA_Dots_external( FLA_MINUS_ONE, a10t, a01, FLA_ONE, alpha11 );

    /*------------------------------------------------------------*/

    FLA_Cont_with_3x3_to_2x2( &ATL, /**/ &ATR,       A00,  a01,     /**/ A02,
                                                     a10t, alpha11, /**/ a12t,
                            /* ************** */  /* ************************ */
                              &ABL, /**/ &ABR,       A20,  a21,     /**/ A22,
                              FLA_TL );

  }

  if ( FLA_Obj_length( ABL ) > 0 )
    // ABL = ABL / triu( ATL )
    FLA_Trsm_external( FLA_RIGHT, FLA_UPPER_TRIANGULAR, 
                       FLA_NO_TRANSPOSE, FLA_NONUNIT_DIAG,
                       FLA_ONE, ATL, ABL );
  else if ( FLA_Obj_width( ATR ) > 0 )
    // ATR = trilu( ATL ) \ ATR
    FLA_Trsm_external( FLA_LEFT, FLA_LOWER_TRIANGULAR, 
                       FLA_NO_TRANSPOSE, FLA_UNIT_DIAG,
                       FLA_ONE, ATL, ATR );

  return FLA_SUCCESS;
}