Function test_kcentroid_with_offset_sparse_linear_kernel

dlib/test/kcentroid.cpp:534–652

    template <typename kernel_type>
    void test_kcentroid_with_offset_sparse_linear_kernel(
    )
    /*!
        requires
            - kernel_type::sample_type == a std::map<unsigned long,double> 
            - kernel_type == a kernel that just computes a dot product
              between its inputs + some constant.  I.e. a linear kernel
              wrapped by offset_kernel
        ensures
            - tests the kcentroid object with the given kernel
    !*/
    {
        // Here we declare that our samples will be 2 dimensional column vectors.  
        typedef typename kernel_type::sample_type sample_type;

        kernel_type k;
        kcentroid<kernel_type> test(k,0.001,20);

        sample_type temp, temp2, temp3;

        std::map<unsigned long,double> val, val2;

        const double b = std::sqrt(k.offset);

        temp.clear();
        temp[0] = 2;
        temp2.clear();
        val.clear();
        DLIB_TEST(approx_equal(test(temp), dist(k,temp,val)));
        DLIB_TEST(approx_equal(test(temp2), dist(k,temp2,val)));
        DLIB_TEST(approx_equal(test.squared_norm(), length_squared(val)));


        temp2.clear();

        // make test store the point(0,0,0,0,b)
        val.clear();
        val[4] = b;
        test.train(temp2, 0,1);

        temp.clear();
        temp[0] = 2;
        dlog << LDEBUG << test(temp) ;
        dlog << LDEBUG << "squared_norm(): " << test.squared_norm() ;

        DLIB_TEST(approx_equal(test(temp), dist(k,temp,val)));
        DLIB_TEST(approx_equal(test(temp2), dist(k,temp2,val)));
        DLIB_TEST_MSG(approx_equal(test.get_distance_function()(temp2), dist(k,temp2,val), 1e-7), 
                     test.get_distance_function()(temp2) - dist(k,temp2,val)
        );
        DLIB_TEST(approx_equal(test.squared_norm(), length_squared(val)));
        DLIB_TEST(approx_equal(test(test), 0));
        DLIB_TEST(approx_equal(test.get_distance_function()(test.get_distance_function()), 0, 1e-6));

        // make test store the point(0,0,0,0,0)
        val.clear();
        test.train(temp2, 1,-1);