direct_access.cpp

来自「矩阵运算源码最新版本」· C++ 代码 · 共 35 行

// Software License for MTL
// 
// Copyright (c) 2007 The Trustees of Indiana University. All rights reserved.
// Authors: Peter Gottschling and Andrew Lumsdaine
// 
// This file is part of the Matrix Template Library
// 
// See also license.mtl.txt in the distribution.

#include <boost/numeric/mtl/mtl.hpp>
#include <iostream>
#include <boost/test/minimal.hpp>

int test_main(int argc, char* argv[])
{
    using namespace mtl; using namespace mtl::matrix;
    
    const unsigned n= 100;
    dense2D<double>                            A(n, n);
    morton_dense<double, doppled_64_row_mask>  C(n, n);

    A[0][0]= 71.; C[0][0]= 72.;

    double *ap= &A[0][0], *cp= &C[0][0];
    std::cout << *ap << '\n';
    if (*ap != 71) throw "wrong value";

    // the direct access of the first element should only be used when absolutely necessary 
    double *ap2= A.elements(), *cp2= C.elements();
    std::cout << *ap2 << '\n';
    if (*ap2 != 71) throw "wrong value";

    return 0;
}