Fix regular grid for d=1; add tests.

mwhutils/random/random.py

@@ -88,7 +88,7 @@ def sobol(bounds, n, rng=None):
     return X
 
 
-def grid(bounds, n, rng=None):
+def grid(bounds, n):
     """
     Generate a regular grid within the specified region, given by `bounds`,
     a list of [(lo,hi), ..] bounds in each dimension. `n` represents the number
@@ -97,7 +97,11 @@ def grid(bounds, n, rng=None):
     bounds = np.array(bounds, ndmin=2, copy=False)
     d = len(bounds)
 
-    X = np.meshgrid(*(np.linspace(a, b, n) for a, b in bounds))
-    X = np.reshape(X, (d, -1)).T
+    if d == 1:
+        X = np.linspace(bounds[0, 0], bounds[0, 1], n)
+        X = np.reshape(X, (-1, 1))
+    else:
+        X = np.meshgrid(*(np.linspace(a, b, n) for a, b in bounds))
+        X = np.reshape(X, (d, -1)).T
 
     return X

tests/test_random.py

@@ -9,7 +9,7 @@
 import numpy.testing as nt
 
 from mwhutils.random import rstate
-from mwhutils.random import uniform, latin, sobol
+from mwhutils.random import uniform, latin, sobol, grid
 
 
 def test_rstate():
@@ -28,11 +28,27 @@ def check_random(method):
     bounds = [(0, 1), (3, 4)]
     sample = method(bounds, 10)
     assert sample.shape == (10, 2)
-    assert all(sample[:, 0] > 0) and all(sample[:, 0] < 1)
-    assert all(sample[:, 1] > 3) and all(sample[:, 1] < 4)
+    assert all(sample[:, 0] >= 0) and all(sample[:, 0] <= 1)
+    assert all(sample[:, 1] >= 3) and all(sample[:, 1] <= 4)
+
+    sample = grid((0, 1), 10)
+    assert sample.shape == (10, 1)
+    assert all(sample[:, 0] >= 0) and all(sample[:, 0] <= 1)
 
 
 def test_random():
     """Test all the random generators."""
     for method in [uniform, latin, sobol]:
         yield check_random, method
+
+
+def test_grid():
+    """Test the non-random grid "sampler"."""
+    sample = grid([(0, 1), (3, 4)], 10)
+    assert sample.shape == (100, 2)
+    assert all(sample[:, 0] >= 0) and all(sample[:, 0] <= 1)
+    assert all(sample[:, 1] >= 3) and all(sample[:, 1] <= 4)
+
+    sample = grid((0, 1), 10)
+    assert sample.shape == (10, 1)
+    assert all(sample[:, 0] >= 0) and all(sample[:, 0] <= 1)