Function luTester

test/lu_dense.cpp:129–186

template<typename T>
void luTester(const int m, const int n, double eps) {
    SUPPORTED_TYPE_CHECK(T);
    LAPACK_ENABLED_CHECK();

#if 1
    array a_orig = cpu_randu<T>(dim4(m, n));
#else
    array a_orig = randu(m, n, (dtype)dtype_traits<T>::af_type);
#endif

    //! [ex_lu_unpacked]
    array l, u, pivot;
    lu(l, u, pivot, a_orig);
    //! [ex_lu_unpacked]

    //! [ex_lu_recon]
    array a_recon = matmul(l, u);
    array a_perm  = a_orig(pivot, span);
    //! [ex_lu_recon]

    ASSERT_NEAR(
        0,
        max<typename dtype_traits<T>::base_type>(abs(real(a_recon - a_perm))),
        eps);
    ASSERT_NEAR(
        0,
        max<typename dtype_traits<T>::base_type>(abs(imag(a_recon - a_perm))),
        eps);

    //! [ex_lu_packed]
    array out = a_orig.copy();
    array pivot2;
    luInPlace(pivot2, out, false);
    //! [ex_lu_packed]

    //! [ex_lu_extract]
    array l2 = lower(out, true);
    array u2 = upper(out, false);
    //! [ex_lu_extract]

    ASSERT_EQ(count<uint>(pivot == pivot2), pivot.elements());

    int mn = std::min(m, n);
    l2     = l2(span, seq(mn));
    u2     = u2(seq(mn), span);

    array a_recon2 = matmul(l2, u2);
    array a_perm2  = a_orig(pivot2, span);

    ASSERT_NEAR(
        0,
        max<typename dtype_traits<T>::base_type>(abs(real(a_recon2 - a_perm2))),
        eps);
    ASSERT_NEAR(
        0,
        max<typename dtype_traits<T>::base_type>(abs(imag(a_recon2 - a_perm2))),
        eps);
}