Merge pull request #248 from kevinsung/sample-seed

fix MPS sample handling of RNG seed

quimb/tensor/tensor_1d.py

@@ -6,6 +6,7 @@
 from math import log, log2
 from numbers import Integral
 
+import numpy as np
 import scipy.sparse.linalg as spla
 from autoray import conj, dag, do, get_dtype_name, reshape, size, transpose
 
@@ -3266,8 +3267,9 @@ def sample(self, C, seed=None, info=None):
         # do right canonicalization once (supplying info avoids re-performing)
         psi0 = self.canonicalize(0, info=info)
 
+        rng = np.random.default_rng(seed)
         for _ in range(C):
-            yield psi0.sample_configuration(seed=seed, info=info)
+            yield psi0.sample_configuration(seed=rng, info=info)
 
 class MatrixProductOperator(TensorNetwork1DOperator, TensorNetwork1DFlat):
     """Initialise a matrix product operator, with auto labelling and tagging.

tests/test_tensor/test_circuit.py

@@ -696,6 +696,13 @@ def test_mps_sampling(self):
         for x in circ.sample(10):
             assert x in {"000010", "111101"}
 
+    def test_mps_sampling_seed(self):
+        N = 1
+        circ = qtn.CircuitMPS(N)
+        circ.h(0)
+        samples = list(circ.sample(10, seed=1234))
+        assert len(set(samples)) == 2
+
     def test_permmps_sampling(self):
         N = 6
         circ = qtn.CircuitPermMPS(N)
@@ -710,6 +717,13 @@ def test_permmps_sampling(self):
         for x in circ.sample(10):
             assert x in {"000010", "111101"}
 
+    def test_permmps_sampling_seed(self):
+        N = 1
+        circ = qtn.CircuitPermMPS(N)
+        circ.h(0)
+        samples = list(circ.sample(10, seed=1234))
+        assert len(set(samples)) == 2
+
 
 class TestCircuitGen:
     @pytest.mark.parametrize(

tests/test_tensor/test_tensor_1d.py

@@ -767,6 +767,14 @@ def test_sample_configuration(self):
             ).contract()
         ) ** 2 == pytest.approx(omega)
 
+    def test_sample_seed(self):
+        psi = qtn.MPS_rand_state(10, 7)
+        configs = [
+            "".join(map(str, config))
+            for config, _ in psi.sample(10, seed=1234)
+        ]
+        assert len(set(configs)) > 1
+
 
 class TestMatrixProductOperator:
     @pytest.mark.parametrize("cyclic", [False, True])