fully revert tensor changes in dim_grid (#460)

Summary:
Pull Request resolved: #460

dim_grid tensor changes were only half reverted for some reason. This fully reverts it and fixes a bug where dim_grid was producing double the number of points when slicing.

Reviewed By: crasanders

Differential Revision: D66374663

fbshipit-source-id: c2226b59c6320bedf74c3374f6ae1347f47e4e26

Author: JasonKChow

aepsych/utils.py

@@ -63,15 +63,11 @@ def dim_grid(
 
     for i in range(dim):
         if i in slice_dims.keys():
-            mesh_vals.append(
-                torch.tensor([slice_dims[i] - 1e-10, slice_dims[i] + 1e-10])
-            )
+            mesh_vals.append(slice(slice_dims[i] - 1e-10, slice_dims[i] + 1e-10, 1))
         else:
-            mesh_vals.append(torch.linspace(lower[i].item(), upper[i].item(), gridsize))
+            mesh_vals.append(slice(lower[i].item(), upper[i].item(), gridsize * 1j))
 
-    return torch.stack(torch.meshgrid(*mesh_vals, indexing="ij"), dim=-1).reshape(
-        -1, dim
-    )
+    return torch.Tensor(np.mgrid[mesh_vals].reshape(dim, -1).T)
 
 
 def _process_bounds(

tests/test_utils.py

@@ -10,7 +10,7 @@
 import numpy as np
 import torch
 from aepsych.models import GPClassificationModel
-from aepsych.utils import _process_bounds, make_scaled_sobol
+from aepsych.utils import _process_bounds, dim_grid, make_scaled_sobol
 
 
 class UtilsTestCase(unittest.TestCase):
@@ -35,6 +35,13 @@ def test_dim_grid_model_size(self):
         grid = GPClassificationModel.dim_grid(mb, gridsize=gridsize)
         self.assertEqual(grid.shape, torch.Size([10, 1]))
 
+    def test_dim_grid_slice(self):
+        lb = torch.tensor([0, 0, 0])
+        ub = torch.tensor([1, 1, 1])
+        grid = dim_grid(lb, ub, slice_dims={1: 0.5})
+
+        self.assertTrue(np.all(grid.shape == (900, 3)))
+
     def test_process_bounds(self):
         lb, ub, dim = _process_bounds(np.r_[0, 1], np.r_[2, 3], None)
         self.assertTrue(torch.all(lb == torch.tensor([0.0, 1.0])))