toqito.matrix_ops.calculate_vector_matrix_dimension

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

Module Contents

toqito.matrix_ops.calculate_vector_matrix_dimension.calculate_vector_matrix_dimension(item)[source]

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

  • square 2D –

  • array (density matrix). –

Parameters:

  • item (numpy.ndarray) – The item whose dimension is being calculated. Can be a 1D array (vector), a 2D array representing a vector

  • 1 (with one dimension being)

  • array (or a square 2D)

Returns:

The dimension of the vector or matrix.

Return type:

int