Bbonev/gradient test fix (#53)

* added analytic gradients to the gradient_analysis notebook

* fixing sht unittest to not check the roundtrip gradient but sht and isht individually

* Updated changelog

Changelog.md

@@ -6,6 +6,7 @@
 
 * Added resampling modules for convenience
 * Changing behavior of distributed SHT to use `dim=-3` as channel dimension
+* Fixing SHT unittests to test SHT and ISHT individually, rather than the roundtrip
 
 ### v0.7.1
 

tests/test_sht.py

@@ -2,7 +2,7 @@
 
 # SPDX-FileCopyrightText: Copyright (c) 2022 The torch-harmonics Authors. All rights reserved.
 # SPDX-License-Identifier: BSD-3-Clause
-# 
+#
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
 #
@@ -37,24 +37,25 @@ import torch
 from torch.autograd import gradcheck
 from torch_harmonics import *
 
+
 class TestLegendrePolynomials(unittest.TestCase):
 
     def setUp(self):
-        self.cml = lambda m, l : np.sqrt((2*l + 1) / 4 / np.pi) * np.sqrt(math.factorial(l-m) / math.factorial(l+m))
+        self.cml = lambda m, l: np.sqrt((2 * l + 1) / 4 / np.pi) * np.sqrt(math.factorial(l - m) / math.factorial(l + m))
         self.pml = dict()
 
         # preparing associated Legendre Polynomials (These include the Condon-Shortley phase)
         # for reference see e.g. https://en.wikipedia.org/wiki/Associated_Legendre_polynomials
-        self.pml[(0, 0)] = lambda x : np.ones_like(x)
-        self.pml[(0, 1)] = lambda x : x
-        self.pml[(1, 1)] = lambda x : - np.sqrt(1. - x**2)
-        self.pml[(0, 2)] = lambda x : 0.5 * (3*x**2 - 1)
-        self.pml[(1, 2)] = lambda x : - 3 * x * np.sqrt(1. - x**2)
-        self.pml[(2, 2)] = lambda x : 3 * (1 - x**2)
-        self.pml[(0, 3)] = lambda x : 0.5 * (5*x**3 - 3*x)
-        self.pml[(1, 3)] = lambda x : 1.5 * (1 - 5*x**2) * np.sqrt(1. - x**2)
-        self.pml[(2, 3)] = lambda x : 15 * x * (1 - x**2)
-        self.pml[(3, 3)] = lambda x : -15 * np.sqrt(1. - x**2)**3
+        self.pml[(0, 0)] = lambda x: np.ones_like(x)
+        self.pml[(0, 1)] = lambda x: x
+        self.pml[(1, 1)] = lambda x: -np.sqrt(1.0 - x**2)
+        self.pml[(0, 2)] = lambda x: 0.5 * (3 * x**2 - 1)
+        self.pml[(1, 2)] = lambda x: -3 * x * np.sqrt(1.0 - x**2)
+        self.pml[(2, 2)] = lambda x: 3 * (1 - x**2)
+        self.pml[(0, 3)] = lambda x: 0.5 * (5 * x**3 - 3 * x)
+        self.pml[(1, 3)] = lambda x: 1.5 * (1 - 5 * x**2) * np.sqrt(1.0 - x**2)
+        self.pml[(2, 3)] = lambda x: 15 * x * (1 - x**2)
+        self.pml[(3, 3)] = lambda x: -15 * np.sqrt(1.0 - x**2) ** 3
 
         self.lmax = self.mmax = 4
 
@@ -68,8 +69,8 @@ class TestLegendrePolynomials(unittest.TestCase):
         vdm = legpoly(self.mmax, self.lmax, t)
 
         for l in range(self.lmax):
-            for m in range(l+1):
-                diff = vdm[m, l] / self.cml(m,l) - self.pml[(m,l)](t)
+            for m in range(l + 1):
+                diff = vdm[m, l] / self.cml(m, l) - self.pml[(m, l)](t)
                 self.assertTrue(diff.max() <= self.tol)
 
 
@@ -79,19 +80,21 @@ class TestSphericalHarmonicTransform(unittest.TestCase):
 
         if torch.cuda.is_available():
             print("Running test on GPU")
-            self.device = torch.device('cuda')
+            self.device = torch.device("cuda")
         else:
             print("Running test on CPU")
-            self.device = torch.device('cpu')
-
-    @parameterized.expand([
-        [256, 512, 32, "ortho",   "equiangular",    1e-9],
-        [256, 512, 32, "ortho",   "legendre-gauss", 1e-9],
-        [256, 512, 32, "four-pi", "equiangular",    1e-9],
-        [256, 512, 32, "four-pi", "legendre-gauss", 1e-9],
-        [256, 512, 32, "schmidt", "equiangular",    1e-9],
-        [256, 512, 32, "schmidt", "legendre-gauss", 1e-9],
-    ])
+            self.device = torch.device("cpu")
+
+    @parameterized.expand(
+        [
+            [256, 512, 32, "ortho", "equiangular", 1e-9],
+            [256, 512, 32, "ortho", "legendre-gauss", 1e-9],
+            [256, 512, 32, "four-pi", "equiangular", 1e-9],
+            [256, 512, 32, "four-pi", "legendre-gauss", 1e-9],
+            [256, 512, 32, "schmidt", "equiangular", 1e-9],
+            [256, 512, 32, "schmidt", "legendre-gauss", 1e-9],
+        ]
+    )
     def test_sht(self, nlat, nlon, batch_size, norm, grid, tol):
         print(f"Testing real-valued SHT on {nlat}x{nlon} {grid} grid with {norm} normalization")
 
@@ -109,30 +112,38 @@ class TestSphericalHarmonicTransform(unittest.TestCase):
             coeffs = torch.zeros(batch_size, lmax, mmax, device=self.device, dtype=torch.complex128)
             coeffs[:, :lmax, :mmax] = torch.randn(batch_size, lmax, mmax, device=self.device, dtype=torch.complex128)
             signal = isht(coeffs)
-        
+
         # testing error accumulation
         for iter in testiters:
-            with self.subTest(i = iter):
+            with self.subTest(i=iter):
                 print(f"{iter} iterations of batchsize {batch_size}:")
 
                 base = signal
 
                 for _ in range(iter):
                     base = isht(sht(base))
-            
-                err = torch.mean(torch.norm(base-signal, p='fro', dim=(-1,-2)) / torch.norm(signal, p='fro', dim=(-1,-2)) )
+
+                err = torch.mean(torch.norm(base - signal, p="fro", dim=(-1, -2)) / torch.norm(signal, p="fro", dim=(-1, -2)))
                 print(f"final relative error: {err.item()}")
                 self.assertTrue(err.item() <= tol)
 
-    @parameterized.expand([
-        [12, 24, 2, "ortho",   "equiangular",    1e-5],
-        [12, 24, 2, "ortho",   "legendre-gauss", 1e-5],
-        [12, 24, 2, "four-pi", "equiangular",    1e-5],
-        [12, 24, 2, "four-pi", "legendre-gauss", 1e-5],
-        [12, 24, 2, "schmidt", "equiangular",    1e-5],
-        [12, 24, 2, "schmidt", "legendre-gauss", 1e-5],
-    ])
-    def test_sht_grad(self, nlat, nlon, batch_size, norm, grid, tol):
+    @parameterized.expand(
+        [
+            [12, 24, 2, "ortho", "equiangular", 1e-5],
+            [12, 24, 2, "ortho", "legendre-gauss", 1e-5],
+            [12, 24, 2, "four-pi", "equiangular", 1e-5],
+            [12, 24, 2, "four-pi", "legendre-gauss", 1e-5],
+            [12, 24, 2, "schmidt", "equiangular", 1e-5],
+            [12, 24, 2, "schmidt", "legendre-gauss", 1e-5],
+            [15, 30, 2, "ortho", "equiangular", 1e-5],
+            [15, 30, 2, "ortho", "legendre-gauss", 1e-5],
+            [15, 30, 2, "four-pi", "equiangular", 1e-5],
+            [15, 30, 2, "four-pi", "legendre-gauss", 1e-5],
+            [15, 30, 2, "schmidt", "equiangular", 1e-5],
+            [15, 30, 2, "schmidt", "legendre-gauss", 1e-5],
+        ]
+    )
+    def test_sht_grads(self, nlat, nlon, batch_size, norm, grid, tol):
         print(f"Testing gradients of real-valued SHT on {nlat}x{nlon} {grid} grid with {norm} normalization")
 
         if grid == "equiangular":
@@ -148,12 +159,19 @@ class TestSphericalHarmonicTransform(unittest.TestCase):
             coeffs = torch.zeros(batch_size, lmax, mmax, device=self.device, dtype=torch.complex128)
             coeffs[:, :lmax, :mmax] = torch.randn(batch_size, lmax, mmax, device=self.device, dtype=torch.complex128)
             signal = isht(coeffs)
-        
+
+        # test the sht
         grad_input = torch.randn_like(signal, requires_grad=True)
-        err_handle = lambda x : torch.mean(torch.norm( isht(sht(x)) - signal , p='fro', dim=(-1,-2)) / torch.norm(signal, p='fro', dim=(-1,-2)) )
+        err_handle = lambda x: torch.mean(torch.norm(sht(x) - coeffs, p="fro", dim=(-1, -2)) / torch.norm(coeffs, p="fro", dim=(-1, -2)))
+        test_result = gradcheck(err_handle, grad_input, eps=1e-6, atol=tol)
+        self.assertTrue(test_result)
+
+        # test the isht
+        grad_input = torch.randn_like(coeffs, requires_grad=True)
+        err_handle = lambda x: torch.mean(torch.norm(isht(x) - signal, p="fro", dim=(-1, -2)) / torch.norm(signal, p="fro", dim=(-1, -2)))
         test_result = gradcheck(err_handle, grad_input, eps=1e-6, atol=tol)
         self.assertTrue(test_result)
 
 
-if __name__ == '__main__':
-    unittest.main()
\ No newline at end of file
+if __name__ == "__main__":
+    unittest.main()