code: def log_map_euclid(X, Cref):
      r"""Project matrices in tangent space by Euclidean logarithmic map.
  
      The projection of a matrix :math:`\mathbf{X}` from manifold
      to tangent space by Euclidean logarithmic map
      according to a reference matrix :math:`\mathbf{C}_\text{ref}` is:
  
      .. math::
          \mathbf{X}_\text{new} = \mathbf{X} - \mathbf{C}_\text{ref}
  
      Parameters
      ----------
      X : ndarray, shape (..., n, m)
          Matrices in manidold.
      Cref : ndarray, shape (n, m)
          The reference matrix.
  
      Returns
      -------
      X_new : ndarray, shape (..., n, m)
          Matrices projected in tangent space.
  
      Notes
      -----
      .. versionadded:: 0.4
      """
      return X - Cref
  
file_path: pyRiemann/pyriemann/utils/tangentspace.py
imports: import numpy
  from .base import sqrtm, invsqrtm, logm, expm
  from .mean import mean_covariance
label_desc: Use image node_id 5 for calling a global function with example usage: log_map_euclid(X, Cref) and returns: unknown