Removed CholeskyGrad Op

Author: sudarsan2k5

pytensor/tensor/slinalg.py

@@ -129,73 +129,6 @@ def conjugate_solve_triangular(outer, inner):
 cholesky = Cholesky()
 
 
-class CholeskyGrad(Op):
-    """"""
-
-    __props__ = ("lower", "destructive")
-
-    def __init__(self, lower=True):
-        self.lower = lower
-        self.destructive = False
-
-    def make_node(self, x, l, dz):
-        x = as_tensor_variable(x)
-        l = as_tensor_variable(l)
-        dz = as_tensor_variable(dz)
-        assert x.ndim == 2
-        assert l.ndim == 2
-        assert dz.ndim == 2
-        assert (
-            l.owner.op.lower == self.lower
-        ), "lower/upper mismatch between Cholesky op and CholeskyGrad op"
-        return Apply(self, [x, l, dz], [x.type()])
-
-    def perform(self, node, inputs, outputs):
-        """
-        Implements the "reverse-mode" gradient [#]_ for the
-        Cholesky factorization of a positive-definite matrix.
-
-        References
-        ----------
-        .. [#] S. P. Smith. "Differentiation of the Cholesky Algorithm".
-           Journal of Computational and Graphical Statistics,
-           Vol. 4, No. 2 (Jun.,1995), pp. 134-147
-           http://www.jstor.org/stable/1390762
-
-        """
-        x = inputs[0]
-        L = inputs[1]
-        dz = inputs[2]
-        dx = outputs[0]
-        N = x.shape[0]
-        if self.lower:
-            F = np.tril(dz)
-            for k in range(N - 1, -1, -1):
-                for j in range(k + 1, N):
-                    for i in range(j, N):
-                        F[i, k] -= F[i, j] * L[j, k]
-                        F[j, k] -= F[i, j] * L[i, k]
-                for j in range(k + 1, N):
-                    F[j, k] /= L[k, k]
-                    F[k, k] -= L[j, k] * F[j, k]
-                F[k, k] /= 2 * L[k, k]
-        else:
-            F = np.triu(dz)
-            for k in range(N - 1, -1, -1):
-                for j in range(k + 1, N):
-                    for i in range(j, N):
-                        F[k, i] -= F[j, i] * L[k, j]
-                        F[k, j] -= F[j, i] * L[k, i]
-                for j in range(k + 1, N):
-                    F[k, j] /= L[k, k]
-                    F[k, k] -= L[k, j] * F[k, j]
-                F[k, k] /= 2 * L[k, k]
-        dx[0] = F
-
-    def infer_shape(self, fgraph, node, shapes):
-        return [shapes[0]]
-
-
 class CholeskySolve(Op):
 
     __props__ = ("lower", "check_finite")

tests/tensor/test_slinalg.py

@@ -11,7 +11,6 @@
 from pytensor.configdefaults import config
 from pytensor.tensor.slinalg import (
     Cholesky,
-    CholeskyGrad,
     CholeskySolve,
     Solve,
     SolveBase,
@@ -122,22 +121,17 @@ def test_cholesky_grad_indef():
 
 
 @pytest.mark.slow
-def test_cholesky_and_cholesky_grad_shape():
+def test_cholesky_shape():
     rng = np.random.default_rng(utt.fetch_seed())
     x = matrix()
     for l in (cholesky(x), Cholesky(lower=True)(x), Cholesky(lower=False)(x)):
         f_chol = pytensor.function([x], l.shape)
-        g = pytensor.gradient.grad(l.sum(), x)
-        f_cholgrad = pytensor.function([x], g.shape)
         topo_chol = f_chol.maker.fgraph.toposort()
-        topo_cholgrad = f_cholgrad.maker.fgraph.toposort()
         if config.mode != "FAST_COMPILE":
             assert sum(node.op.__class__ == Cholesky for node in topo_chol) == 0
-            assert sum(node.op.__class__ == CholeskyGrad for node in topo_cholgrad) == 0
         for shp in [2, 3, 5]:
             m = np.cov(rng.standard_normal((shp, shp + 10))).astype(config.floatX)
             np.testing.assert_equal(f_chol(m), (shp, shp))
-            np.testing.assert_equal(f_cholgrad(m), (shp, shp))
 
 
 def test_eigvalsh():