Streamline properties

Author: thangleiter

filter_functions/basis.py

@@ -237,6 +237,13 @@ def _print_checks(self) -> None:
         for check in checks:
             print(check, ':\t', getattr(self, check))
 
+    def _invalidate_cached_properties(self):
+        for attr in {'isherm', 'isnorm', 'isorthogonal', 'istraceless', 'iscomplete'}:
+            try:
+                delattr(self, attr)
+            except AttributeError:
+                pass
+
     @cached_property
     def isherm(self) -> bool:
         """Returns True if all basis elements are hermitian."""
@@ -248,22 +255,25 @@ def isnorm(self) -> bool:
         return self.normalize(copy=True) == self
 
     @cached_property
-    def isorthonorm(self) -> bool:
-        """Returns True if basis is orthonormal."""
-        # All the basis is orthonormal iff the matrix consisting of all
-        # d**2 elements written as d**2-dimensional column vectors is
-        # unitary.
+    def isorthogonal(self) -> bool:
+        """Returns True if all basis elements are mutually orthogonal."""
         if self.ndim == 2 or len(self) == 1:
-            # Only one basis element
             return True
-        else:
-            # Size of the result after multiplication
-            dim = self.shape[0]
-            U = self.reshape((dim, -1))
-            actual = U.conj() @ U.T
-            target = np.identity(dim)
-            atol = self._eps*(self.d**2)**3
-            return np.allclose(actual.view(np.ndarray), target, atol=atol, rtol=self._rtol)
+
+        # The basis is orthogonal iff the matrix consisting of all d**2
+        # elements written as d**2-dimensional column vectors is
+        # orthogonal.
+        dim = self.shape[0]
+        U = self.reshape((dim, -1))
+        actual = U.conj() @ U.T
+        atol = self._eps*(self.d**2)**3
+        mask = np.identity(dim, dtype=bool)
+        return np.allclose(actual[..., ~mask].view(np.ndarray), 0, atol=atol, rtol=self._rtol)
+
+    @property
+    def isorthonorm(self) -> bool:
+        """Returns True if basis is orthonormal."""
+        return self.isorthogonal and self.isnorm
 
     @cached_property
     def istraceless(self) -> bool:
@@ -366,6 +376,7 @@ def normalize(self, copy: bool = False) -> Union[None, 'Basis']:
             return normalize(self)
 
         self /= _norm(self)
+        self._invalidate_cached_properties()
 
     def tidyup(self, eps_scale: Optional[float] = None) -> None:
         """Wraps util.remove_float_errors."""
@@ -377,6 +388,8 @@ def tidyup(self, eps_scale: Optional[float] = None) -> None:
         self.real[np.abs(self.real) <= atol] = 0
         self.imag[np.abs(self.imag) <= atol] = 0
 
+        self._invalidate_cached_properties()
+
     @classmethod
     def pauli(cls, n: int) -> 'Basis':
         r"""
@@ -544,8 +557,8 @@ def _full_from_partial(elems: Sequence, traceless: bool, labels: Sequence[str])
     if not elems.isherm:
         warn("(Some) elems not hermitian! The resulting basis also won't be.")
 
-    if not elems.isorthonorm:
-        raise ValueError("The basis elements are not orthonormal!")
+    if not elems.isorthogonal:
+        raise ValueError("The basis elements are not orthogonal!")
 
     if traceless is None:
         traceless = elems.istraceless
@@ -631,7 +644,7 @@ def normalize(b: Basis) -> Basis:
         Baltimore, MD, Johns Hopkins University Press, 1985, pg. 15
 
     """
-    return (b/_norm(b)).squeeze().view(Basis)
+    return (b/_norm(b)).squeeze().reshape(b.shape).view(Basis)
 
 
 def expand(M: Union[np.ndarray, Basis], basis: Union[np.ndarray, Basis],

tests/test_basis.py

@@ -24,7 +24,6 @@
 from copy import copy
 from itertools import product
 
-import filter_functions as ff
 import numpy as np
 import pytest
 from opt_einsum import contract
@@ -109,6 +108,7 @@ def test_basis_properties(self):
         pauli_basis = ff.Basis.pauli(n)
         from_partial_basis = ff.Basis.from_partial(testutil.rand_herm(d), traceless=False)
         custom_basis = ff.Basis(testutil.rand_herm_traceless(d))
+        custom_basis /= np.linalg.norm(custom_basis, ord='fro', axis=(-1, -2))
 
         btypes = ('Pauli', 'GGM', 'From partial', 'Custom')
         bases = (pauli_basis, ggm_basis, from_partial_basis, custom_basis)
@@ -127,6 +127,8 @@ def test_basis_properties(self):
                 self.assertTrue(base[rng.integers(0, len(base))] in base)
             # Check if all elements of each basis are orthonormal and hermitian
             self.assertArrayEqual(base.T, base.view(np.ndarray).swapaxes(-1, -2))
+            self.assertTrue(base.isnorm)
+            self.assertTrue(base.isorthogonal)
             self.assertTrue(base.isorthonorm)
             self.assertTrue(base.isherm)
             # Check if basis spans the whole space and all elems are traceless
@@ -137,6 +139,9 @@ def test_basis_properties(self):
 
             if not btype == 'Custom':
                 self.assertTrue(base.iscomplete)
+            else:
+                self.assertFalse(base.iscomplete)
+
             # Check sparse representation
             self.assertArrayEqual(base.sparse.todense(), base)
             # Test sparse cache
@@ -154,9 +159,17 @@ def test_basis_properties(self):
 
             base._print_checks()
 
-        # single element always considered orthonormal
-        orthonorm = rng.normal(size=(d, d))
-        self.assertTrue(orthonorm.view(ff.Basis).isorthonorm)
+        # single element always considered orthogonal
+        orthogonal = rng.normal(size=(d, d))
+        self.assertTrue(orthogonal.view(ff.Basis).isorthogonal)
+
+        orthogonal /= np.linalg.norm(orthogonal, 'fro', axis=(-1, -2))
+        self.assertTrue(orthogonal.view(ff.Basis).isorthonorm)
+
+        nonorthogonal = rng.normal(size=(3, d, d)).view(ff.Basis)
+        self.assertFalse(nonorthogonal.isnorm)
+        nonorthogonal.normalize()
+        self.assertTrue(nonorthogonal.isnorm)
 
         herm = testutil.rand_herm(d).squeeze()
         self.assertTrue(herm.view(ff.Basis).isherm)
@@ -206,6 +219,22 @@ def test_basis_expansion_and_normalization(self):
         r = ff.basis.ggm_expand(rng.standard_normal((3, 3)), hermitian=False)
         self.assertTrue(r.dtype == 'complex128')
 
+        # test the method
+        pauli = ff.Basis.pauli(1)
+        ggm = ff.Basis.ggm(2)
+
+        M = testutil.rand_herm(2, 3)
+        self.assertArrayAlmostEqual(pauli.expand(M, hermitian=True, traceless=False, tidyup=True),
+                                    ggm.expand(M, hermitian=True, traceless=False, tidyup=True))
+
+        M = testutil.rand_herm_traceless(2, 3)
+        self.assertArrayAlmostEqual(pauli.expand(M, hermitian=True, traceless=True, tidyup=True),
+                                    ggm.expand(M, hermitian=True, traceless=True, tidyup=True))
+
+        M = testutil.rand_unit(2, 3)
+        self.assertArrayAlmostEqual(pauli.expand(M, hermitian=False, traceless=False, tidyup=True),
+                                    ggm.expand(M, hermitian=False, traceless=False, tidyup=True))
+
         for _ in range(10):
             d = rng.integers(2, 16)
             ggm_basis = ff.Basis.ggm(d)