FLA_Chol_l_unb_var1.c File Reference

(r)


Functions

FLA_Error FLA_Chol_l_unb_var1 (FLA_Obj A)

Function Documentation

FLA_Error FLA_Chol_l_unb_var1 ( FLA_Obj  A  ) 

References FLA_Cont_with_3x3_to_2x2(), FLA_Dotcs_external(), FLA_Dots_external(), FLA_MINUS_ONE, FLA_Obj_is_real(), FLA_Obj_length(), FLA_ONE, FLA_Part_2x2(), FLA_Repart_2x2_to_3x3(), FLA_Sqrt(), and FLA_Trsv_external().

00038 {
00039   FLA_Obj ATL,   ATR,      A00,  a01,     A02,
00040           ABL,   ABR,      a10t, alpha11, a12t,
00041                            A20,  a21,     A22;
00042 
00043   int value = 0;
00044 
00045   FLA_Part_2x2( A,    &ATL, &ATR,
00046                       &ABL, &ABR,     0, 0, FLA_TL );
00047 
00048   while ( FLA_Obj_length( ATL ) < FLA_Obj_length( A ) ){
00049 
00050     FLA_Repart_2x2_to_3x3( ATL, /**/ ATR,       &A00,  /**/ &a01,     &A02,
00051                         /* ************* */   /* ************************** */
00052                                                 &a10t, /**/ &alpha11, &a12t,
00053                            ABL, /**/ ABR,       &A20,  /**/ &a21,     &A22,
00054                            1, 1, FLA_BR );
00055 
00056     /*------------------------------------------------------------*/
00057 
00058     if ( FLA_Obj_is_real( A ) )
00059     {
00060       /* a10t = a10t * inv( tril( A00 )' ); */
00061       /* a10t' = inv( tril( A00 ) ) * a10t'; */
00062       FLA_Trsv_external( FLA_LOWER_TRIANGULAR, FLA_NO_TRANSPOSE, FLA_NONUNIT_DIAG, A00, a10t );
00063 
00064       /* alpha11 = alpha11 - a10t * a10t'; */
00065       FLA_Dots_external( FLA_MINUS_ONE, a10t, a10t, FLA_ONE, alpha11 );
00066 
00067       /* alpha11 = sqrt( alpha11 ); */
00068       value = FLA_Sqrt( alpha11 );
00069 
00070       if ( value != FLA_SUCCESS )
00071         return ( FLA_Obj_length( A00 ) + 1 );
00072     }
00073     else
00074     {
00075       /* a10t = a10t * inv( tril( A00 )' ); */
00076       /* a10t' = inv( conj( tril( A00 ) ) ) * a10t'; */
00077       FLA_Trsv_external( FLA_LOWER_TRIANGULAR, FLA_CONJ_NO_TRANSPOSE, FLA_NONUNIT_DIAG, A00, a10t );
00078 
00079       /* alpha11 = alpha11 - a10t * a10t'; */
00080       FLA_Dotcs_external( FLA_CONJUGATE, FLA_MINUS_ONE, a10t, a10t, FLA_ONE, alpha11 );
00081 
00082       /* alpha11 = sqrt( alpha11 ); */
00083       value = FLA_Sqrt( alpha11 );
00084 
00085       if ( value != FLA_SUCCESS )
00086         return ( FLA_Obj_length( A00 ) + 1 );
00087     }
00088 
00089     /*------------------------------------------------------------*/
00090 
00091     FLA_Cont_with_3x3_to_2x2( &ATL, /**/ &ATR,       A00,  a01,     /**/ A02,
00092                                                      a10t, alpha11, /**/ a12t,
00093                             /* ************** */  /* ************************ */
00094                               &ABL, /**/ &ABR,       A20,  a21,     /**/ A22,
00095                               FLA_TL );
00096   }
00097 
00098   return value;
00099 }


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