Interface refactoring

Find a design which is more intuitive and minimal.

codes/params/matrixShaping.py

+import numpy as np
+
+def matrix_to_flat(matrix):
+    """
+    Flatten the upper triangle of a collection of matrices.
+
+    Parameters:
+    -----------
+    matrix : nd-array
+        Array with shape (..., n, n)
+    """
+    return matrix[..., *np.triu_indices(matrix.shape[-1])].flatten()
+
+def flat_to_matrix(flat, shape):
+    """
+    Undo `matrix_to_flat`.
+    
+    Parameters:
+    -----------
+    flat : 1d-array
+        Output from `matrix_to_flat`.
+    shape : 1d-array
+        Shape of the resulting tb model
+    """
+    matrix = np.zeros(shape, dtype=complex)
+    matrix[..., *np.triu_indices(shape[-1])] = flat.reshape(*shape[:-2], -1)
+    indices = np.arange(shape[-1])
+    diagonal = matrix[..., indices, indices]
+    matrix += np.moveaxis(matrix, -1, -2).conj()
+    matrix[..., indices, indices] -= diagonal
+    return matrix
+
+def complex_to_real(z):
+    """
+    Split real and imaginary parts of a complex array.
+
+    Parameters:
+    -----------
+    z : array
+    """
+    return np.concatenate((np.real(z), np.imag(z)))
+
+def real_to_complex(z):
+    """
+    Undo `complex_to_real`.
+    """
+    return z[:len(z)//2] + 1j * z[len(z)//2:]