sign fix for gradient blocks

cornellius-gp · Oct 16, 2024 · 7061ce2 · 7061ce2
1 parent d501c28
commit 7061ce2
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Showing 2 changed files with 8 additions and 9 deletions.
diff --git a/gpytorch/kernels/matern52_kernel_grad.py b/gpytorch/kernels/matern52_kernel_grad.py
@@ -94,15 +94,14 @@ def forward(self, x1, x2, diag=False, **params):
 
             # 2) First gradient block, cov(f^m, omega^n_d)
             outer1 = outer.view(*batch_shape, n1, n2 * d)
-            K[..., :n1, n2:] = outer1 * (-five_thirds * (1 + sqrt5 * distance_matrix) * exp_neg_sqrt5r).repeat(
+            K[..., :n1, n2:] = outer1 * (five_thirds * (1 + sqrt5 * distance_matrix) * exp_neg_sqrt5r).repeat(
                 [*([1] * (n_batch_dims + 1)), d]
             )
 
             # 3) Second gradient block, cov(omega^m_d, f^n)
             outer2 = outer.transpose(-1, -3).reshape(*batch_shape, n2, n1 * d)
             outer2 = outer2.transpose(-1, -2)
-            # the - signs on -outer2 and -five_thirds cancel out
-            K[..., n1:, :n2] = outer2 * (five_thirds * (1 + sqrt5 * distance_matrix) * exp_neg_sqrt5r).repeat(
+            K[..., n1:, :n2] = -outer2 * (five_thirds * (1 + sqrt5 * distance_matrix) * exp_neg_sqrt5r).repeat(
                 [*([1] * n_batch_dims), d, 1]
             )
 

diff --git a/test/kernels/test_matern52_kernel_grad.py b/test/kernels/test_matern52_kernel_grad.py
@@ -21,12 +21,12 @@ def test_kernel(self, cuda=False):
 
         actual = torch.tensor(
             [
-                [0.3056225, -0.0000000, 0.5822443, 0.0188260, -0.0209871, 0.0419742],
-                [0.0000000, 0.5822443, 0.0000000, 0.0209871, -0.0056045, 0.0531832],
-                [-0.5822443, 0.0000000, -0.8515886, -0.0419742, 0.0531832, -0.0853792],
-                [0.1304891, -0.2014212, -0.2014212, 0.0336440, -0.0815567, -0.0000000],
-                [0.2014212, -0.1754366, -0.3768578, 0.0815567, -0.1870145, -0.0000000],
-                [0.2014212, -0.3768578, -0.1754366, 0.0000000, -0.0000000, 0.0407784],
+                [0.3056225, 0.0000000, -0.5822443, 0.0188260, 0.0209871, -0.0419742],
+                [-0.0000000, 0.5822443, 0.0000000, -0.0209871, -0.0056045, 0.0531832],
+                [0.5822443, 0.0000000, -0.8515886, 0.0419742, 0.0531832, -0.0853792],
+                [0.1304891, 0.2014212, 0.2014212, 0.0336440, 0.0815567, 0.0000000],
+                [-0.2014212, -0.1754366, -0.3768578, -0.0815567, -0.1870145, -0.0000000],
+                [-0.2014212, -0.3768578, -0.1754366, -0.0000000, -0.0000000, 0.0407784],
             ]
         )