FLASH_Obj_create_diag_panel.c File Reference

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Functions
FLA_Error	FLASH_Obj_create_diag_panel (FLA_Obj A, FLA_Obj *U)

Function Documentation

FLASH_Obj_create_diag_panel()

FLA_Error FLASH_Obj_create_diag_panel	(	FLA_Obj	A,
		FLA_Obj *	U )

{
    FLA_Datatype datatype;
    dim_t        b_flash;
    dim_t        b_flash_last;
    dim_t        n_blocks_min_dim;
    dim_t        m_U, n_U;
 
    // Acquire the datatype of the matrix to be factored.
    datatype = FLA_Obj_datatype( A );
 
    // Acquire the storage blocksize of the top-left element.
    b_flash = FLASH_Obj_scalar_length_tl( A );
 
    // Get the number of storage blocks in the minimum dimension of A.
    n_blocks_min_dim = FLA_Obj_min_dim( A );
 
    // Compute the scalar length and width of U.
    m_U = b_flash;
    n_U = n_blocks_min_dim * b_flash;
 
    // Create U with storage blocksize of b_flash.
    FLASH_Obj_create( datatype, m_U, n_U, 1, &b_flash, U );
 
    // The last, bottom-right-most diagonal block of A might be smaller
    // than the other diagonal blocks. Compute the size of this block.
    b_flash_last = FLASH_Obj_scalar_min_dim( A ) % b_flash;
 
    // If the remainder is zero, then A does not need its last block
    // shrunk and thus it is ready as-is. However, if b_flash_last is
    // non-zero, then we must manually adjust the size of the last block of
    // U. Note that we are not freeing and re-allocating memory, just
    // changing the size of the view into the last block.
 
    if ( b_flash_last > 0 )
    {
        FLA_Obj  UL,    UR;
        FLA_Obj  URTL,  URTR,
                 URBL,  URBR;
        FLA_Obj* UR_p;
 
        // Repartition U so we can access the last block object.
        FLA_Part_1x2( *U,   &UL, &UR,    1, FLA_RIGHT );
 
        // Dereference the 1x1 object reference to get a pointer to
        // the actual block object in U.
        UR_p = FLASH_OBJ_PTR_AT( UR );
 
        // Repartition the last block object so that URTL is the
        // correct size.
        FLA_Part_2x2( *UR_p,    &URTL, &URTR,
                                &URBL, &URBR,     b_flash_last,
                                                  b_flash_last, FLA_TL );
 
        // Overwrite the original object pointed to by UR_p with the
        // corrected object URTL.
        *UR_p = URTL;
    }
 
    return FLA_SUCCESS;
}

References FLA_Obj_datatype(), FLA_Obj_min_dim(), FLA_Part_1x2(), FLA_Part_2x2(), FLASH_Obj_create(), FLASH_Obj_scalar_length_tl(), and FLASH_Obj_scalar_min_dim().

Referenced by FLASH_LU_incpiv_opt1(), and FLASH_QR_UT_inc_opt1().