psi4.driver.p4util.array_to_matrix(self, arr, name='New Matrix', dim1=None, dim2=None)[source]

Converts a NumPy array or list of NumPy arrays into a PSI4 Matrix or Vector (irrepped if list).

  • self (Union[Matrix, Vector]) – Matrix or Vector class.

  • arr (Union[ndarray, List[ndarray]]) – NumPy array or list of arrays to use as the data for a new Matrix or Vector.

  • name (str) – Name to give the new Matrix.

  • dim1 (Union[List, Tuple, Dimension, None]) – If a single dense NumPy array is given, a dimension can be supplied to apply irreps to this array. Note that this discards all extra information given in the matrix besides the diagonal blocks determined by the passed dimension.

  • dim2 (Optional[Dimension]) – Same as dim1 only if using a Dimension object.


Returns the given (self) Psi4 object.

Return type:

Matrix or Vector


This is a generalized function to convert a NumPy array to a Psi4 object


>>> data = np.random.rand(20,1)
>>> vector = psi4.core.Matrix.from_array(data)
>>> irrep_data = [np.random.rand(2, 2), np.empty(shape=(0,3)), np.random.rand(4, 4)]
>>> matrix = psi4.core.Matrix.from_array(irrep_data)
>>> print(matrix.rowdim().to_tuple())
(2, 0, 4)