Open tienviitta opened 10 months ago
I have unexpexcted results from the matrix_power with even exponents.
void ex1_mpow_run() { xt::xarray<double> arr1{{1, 1, 0}, {1, 0, 1}, {0, 0, 0}}; std::cout << "arr1:" << std::endl << arr1 << std::endl; for (long n = 2; n < 8; ++n) { xt::xarray<double> arr_n = xt::linalg::matrix_power(arr1, n); std::cout << "arr^" << n << ":" << std::endl << arr_n << std::endl; } }
This will give me:
arr1: {{ 1., 1., 0.}, { 1., 0., 1.}, { 0., 0., 0.}} arr^2: {{ 2., 1., 1.}, { 1., 1., 0.}, { 0., 0., 0.}} arr^3: {{ 3., 2., 1.}, { 2., 1., 1.}, { 0., 0., 0.}} arr^4: {{ 1., 1., 0.}, { 1., 0., 1.}, { 0., 0., 0.}} arr^5: {{ 8., 5., 3.}, { 5., 3., 2.}, { 0., 0., 0.}} arr^6: {{ 3., 2., 1.}, { 2., 1., 1.}, { 0., 0., 0.}} arr^7: {{ 21., 13., 8.}, { 13., 8., 5.}, { 0., 0., 0.}}
When I expect these to be as from Octave:
arr1 = 1 1 0 1 0 1 0 0 0 >> arr1 ^ 2 ans = 2 1 1 1 1 0 0 0 0 >> arr1 ^ 3 ans = 3 2 1 2 1 1 0 0 0 >> arr1 ^ 4 ans = 5 3 2 3 2 1 0 0 0 >> arr1 ^ 5 ans = 8 5 3 5 3 2 0 0 0 >> arr1 ^ 6 ans = 13 8 5 8 5 3 0 0 0 >> arr1 ^ 7 ans = 21 13 8 13 8 5 0 0 0
Have I misunderstood something on the usage of this matrix_power? I'm on Ubuntu 22.04 with packages:
lapack 3.9.0 netlib conda-forge libblas 3.9.0 19_linux64_openblas conda-forge libcblas 3.9.0 19_linux64_openblas conda-forge liblapack 3.9.0 19_linux64_openblas conda-forge liblapacke 3.9.0 19_linux64_openblas conda-forge libopenblas 0.3.24 pthreads_h413a1c8_0 conda-forge openblas 0.3.24 pthreads_h7a3da1a_0 conda-forge ... xsimd 7.6.0 h4bd325d_0 conda-forge xtensor 0.23.10 h4bd325d_0 conda-forge xtensor-blas 0.19.2 h4bd325d_0 conda-forge ...
I have unexpexcted results from the matrix_power with even exponents.
This will give me:
When I expect these to be as from Octave:
Have I misunderstood something on the usage of this matrix_power? I'm on Ubuntu 22.04 with packages: