text: # Copyright 2021 The NetKet Authors - All rights reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import pytest
  
  import jax
  import jax.flatten_util
  import numpy as np
  from flax import serialization
  from jax.nn.initializers import normal
  
  import tarfile
  from io import BytesIO
  
  from netket import experimental as nkx
  
  import netket as nk
  
  from .. import common
  
  pytestmark = common.skipif_mpi
  
  SEED = 111
  
  
  @pytest.fixture()
  def vstate(request):
      N = 8
      hi = nk.hilbert.Spin(1 / 2, N)
  
      ma = nk.models.RBM(
          alpha=1,
          dtype=float,
          hidden_bias_init=normal(),
          visible_bias_init=normal(),
      )
  
      return nk.vqs.MCState(
          nk.sampler.MetropolisLocal(hi),
          ma,
      )
  
  
  def test_variables_from_file(vstate, tmp_path):
      fname = str(tmp_path) + "/file.mpack"
  
      with open(fname, "wb") as f:
          f.write(serialization.to_bytes(vstate.variables))
  
      for name in [fname, fname[:-6]]:
          vstate2 = nk.vqs.MCState(
              vstate.sampler, vstate.model, n_samples=10, seed=SEED + 100
          )
  
          vstate2.variables = nkx.vqs.variables_from_file(name, vstate2.variables)
  
          # check
          jax.tree_multimap(
              np.testing.assert_allclose, vstate.parameters, vstate2.parameters
          )
  
  
  def test_variables_from_tar(vstate, tmp_path):
      fname = str(tmp_path) + "/file.tar"
  
      with tarfile.TarFile(fname, "w") as f:
          for i in range(10):
              save_binary_to_tar(
                  f, serialization.to_bytes(vstate.variables), f"{i}.mpack"
              )
  
      for name in [fname, fname[:-4]]:
          vstate2 = nk.vqs.MCState(
              vstate.sampler, vstate.model, n_samples=10, seed=SEED + 100
          )
  
          for j in [0, 3, 8]:
              vstate2.variables = nkx.vqs.variables_from_tar(name, vstate2.variables, j)
  
              # check
              jax.tree_multimap(
                  np.testing.assert_allclose, vstate.parameters, vstate2.parameters
              )
  
          with pytest.raises(KeyError):
              nkx.vqs.variables_from_tar(name, vstate2.variables, 15)
  
  
  def test_deprecated_names():
      with pytest.warns(FutureWarning):
          assert nkx.vqs.variables_from_file == nk.vqs.experimental.variables_from_file
  
      with pytest.warns(FutureWarning):
          assert nkx.vqs.variables_from_tar == nk.vqs.experimental.variables_from_tar
  
  
  def save_binary_to_tar(tar_file, byte_data, name):
      abuf = BytesIO(byte_data)
  
      # Contruct the info object with the correct length
      info = tarfile.TarInfo(name=name)
      info.size = len(abuf.getbuffer())
  
      # actually save the data to the tar file
      tar_file.addfile(tarinfo=info, fileobj=abuf)
  