add backend agnostic tests

Author: refraction-ray

CHANGELOG.md

@@ -6,6 +6,8 @@
 
 - Add `Lattice` module (`tensorcircuit.templates.lattice`) for creating and manipulating various lattice geometries, including `SquareLattice`, `HoneycombLattice`, and `CustomizeLattice`.
 
+- Add `tc.templates.hamiltonians` for commom systems.
+
 - Add `DistributedContractor` in experimental module with new examples for fast implementation of distribution circuit simulation on jax backend.
 
 - Add `circuit.amplitude_before()` method to return the corresponding tensornetwork nodes.

tensorcircuit/templates/__init__.py

@@ -6,5 +6,6 @@
 from . import measurements
 from . import conversions
 from . import lattice
+from . import hamiltonians
 
 costfunctions = measurements

tests/test_hamiltonians.py

@@ -1,7 +1,8 @@
 import pytest
 import numpy as np
-import tensorcircuit as tc
+from pytest_lazyfixture import lazy_fixture as lf
 
+import tensorcircuit as tc
 
 from tensorcircuit.templates.lattice import (
     ChainLattice,
@@ -44,7 +45,8 @@ def test_single_site(self):
         assert h.shape == (2, 2)
         assert h.nnz == 0
 
-    def test_two_sites_chain(self):
+    @pytest.mark.parametrize("backend", [lf("npb"), lf("tfb"), lf("jaxb")])
+    def test_two_sites_chain(self, backend):
         """
         Test a two-site chain against a manually calculated Hamiltonian.
         This is the most critical test for scientific correctness.
@@ -60,7 +62,8 @@ def test_two_sites_chain(self):
         h_expected = j_coupling * (xx + yy + zz)
 
         assert h_generated.shape == (4, 4)
-        assert np.allclose(tc.backend.to_dense(h_generated), h_expected)
+        print(tc.backend.to_dense(h_generated))
+        assert np.allclose(tc.backend.to_dense(h_generated), h_expected, atol=1e-5)
 
     def test_square_lattice_properties(self):
         """
@@ -135,7 +138,8 @@ def test_zero_distance_robustness(self):
         except ZeroDivisionError:
             pytest.fail("The function failed to handle zero distance between sites.")
 
-    def test_anisotropic_heisenberg(self):
+    @pytest.mark.parametrize("backend", [lf("npb"), lf("tfb"), lf("jaxb")])
+    def test_anisotropic_heisenberg(self, backend):
         """
         Test the anisotropic Heisenberg model with different Jx, Jy, Jz.
         """