toqito.matrix_ops.calculate_vector_matrix_dimension
===================================================

.. py:module:: toqito.matrix_ops.calculate_vector_matrix_dimension

.. autoapi-nested-parse::

   Calculates the (common) dimension of a set of vectors or matrices.





Module Contents
---------------

.. py:function:: calculate_vector_matrix_dimension(item)

   Calculate the dimension of a vector or a square matrix, including 2D representations of vectors.

   This function determines the dimension of the provided item, treating 1D arrays as vectors,
   2D arrays with one dimension being 1 as vector representations, and square 2D arrays as density matrices.
   The dimension is the length for vectors and the square of the side length for density matrices.

   Example:
   Consider the following three-dimensional vector:

   \[
       v = \left[ 1, 0, 0 \right]^{\text{T}}.
   \]

   For this case, the dimension of the vector is equal to its length

   ```python exec="1" source="above"
   import numpy as np
   from toqito.matrix_ops import calculate_vector_matrix_dimension

   v = np.array([1, 0, 0])

   print(calculate_vector_matrix_dimension(v))
   ```

   For the density matrix of some two-dimensional quantum system

   \[
       \rho = \frac{1}{2}
               \begin{pmatrix}
                   1 & 0 \\
                   0 & 1
               \end{pmatrix}
   \]

   ```python exec="1" source="above"
   import numpy as np
   from toqito.matrix_ops import calculate_vector_matrix_dimension

   rho = np.array([[1/2, 0],[0, 1/2]])

   print(calculate_vector_matrix_dimension(rho))
   ```

   :returns: The dimension of the item. For vectors (1D or 2D representations), it's the length. For square matrices, it's
             the square of the size of one side.

   :raises ValueError: If the input is not a numpy array, not a 1D array (vector), a 2D array representing a vector, or a
   :raises square 2D:
   :raises array (density matrix).:

   :param item: The item whose dimension is being calculated. Can be a 1D array (vector), a 2D array representing a vector
   :param with one dimension being 1:
   :type with one dimension being 1: density matrix
   :param or a square 2D array:
   :type or a square 2D array: density matrix

   :returns: The dimension of the vector or matrix.