Remove Mean Op

This Op does not really fit the CAReduce API, as it requires an extra bit of information (number of elements in the axis) during the loop. A better solution will be a fused Elemwise+CAReduce

Author: ricardoV94

pytensor/link/numba/dispatch/elemwise.py

@@ -34,7 +34,6 @@
     Add,
     Composite,
     IntDiv,
-    Mean,
     Mul,
     ScalarMaximum,
     ScalarMinimum,
@@ -77,11 +76,6 @@ def scalar_in_place_fn_Sub(op, idx, res, arr):
     return f"{res}[{idx}] -= {arr}"
 
 
-@scalar_in_place_fn.register(Mean)
-def scalar_in_place_fn_Mean(op, idx, res, arr):
-    return f"{res}[{idx}] += ({arr} - {res}[{idx}]) / (i + 1)"
-
-
 @scalar_in_place_fn.register(Mul)
 def scalar_in_place_fn_Mul(op, idx, res, arr):
     return f"{res}[{idx}] *= {arr}"

pytensor/scalar/basic.py

@@ -1871,32 +1871,6 @@ def L_op(self, inputs, outputs, gout):
 add = Add(upcast_out, name="add")
 
 
-class Mean(ScalarOp):
-    identity = 0
-    commutative = True
-    associative = False
-    nfunc_spec = ("mean", 2, 1)
-    nfunc_variadic = "mean"
-
-    def impl(self, *inputs):
-        return sum(inputs) / len(inputs)
-
-    def c_code(self, node, name, inputs, outputs, sub):
-        (z,) = outputs
-        if not inputs:
-            return f"{z} = 0;"
-        else:
-            return f"{z} = ({' + '.join(inputs)}) / ((double) {len(inputs)});"
-
-    def L_op(self, inputs, outputs, gout):
-        (gz,) = gout
-        retval = [gz / len(inputs)] * len(inputs)
-        return retval
-
-
-mean = Mean(float_out, name="mean")
-
-
 class Mul(ScalarOp):
     identity = 1
     commutative = True

pytensor/tensor/math.py

@@ -1316,63 +1316,7 @@ def complex_from_polar(abs, angle):
     """Return complex-valued tensor from polar coordinate specification."""
 
 
-class Mean(FixedOpCAReduce):
-    __props__ = ("axis",)
-    nfunc_spec = ("mean", 1, 1)
-
-    def __init__(self, axis=None):
-        super().__init__(ps.mean, axis)
-        assert self.axis is None or len(self.axis) == 1
-
-    def __str__(self):
-        if self.axis is not None:
-            args = ", ".join(str(x) for x in self.axis)
-            return f"Mean{{{args}}}"
-        else:
-            return "Mean"
-
-    def _output_dtype(self, idtype):
-        # we want to protect against overflow
-        return "float64"
-
-    def perform(self, node, inp, out):
-        (input,) = inp
-        (output,) = out
-        if self.axis is None:
-            axis = None
-        else:
-            axis = self.axis[0]
-        # numpy.asarray is needed as otherwise we can end up with a
-        # numpy scalar.
-        output[0] = np.asarray(np.mean(input, dtype="float64", axis=axis))
-
-    def c_code(self, node, name, inames, onames, sub):
-        ret = super().c_code(node, name, inames, onames, sub)
-
-        if self.axis is not None:
-            return ret
-
-        # TODO: c_code perform support only axis is None
-        return (
-            ret
-            + f"""
-  *((double *)PyArray_DATA({onames[0]})) /= PyArray_SIZE({inames[0]});
-  """
-        )
-
-    def clone(self, **kwargs):
-        axis = kwargs.get("axis", self.axis)
-        return type(self)(axis=axis)
-
-
-# TODO: implement the grad. When done and tested, you can make this the default
-# version.
-#    def grad(self, (x,), (gout,)):
-#      import pdb;pdb.set_trace()
-#      return grad(mean(x, self.axis, op=False),[x])
-
-
-def mean(input, axis=None, dtype=None, op=False, keepdims=False, acc_dtype=None):
+def mean(input, axis=None, dtype=None, keepdims=False, acc_dtype=None):
     """
     Computes the mean value along the given axis(es) of a tensor `input`.
 
@@ -1397,25 +1341,6 @@ def mean(input, axis=None, dtype=None, op=False, keepdims=False, acc_dtype=None)
         be in a float type). If None, then we use the same rules as `sum()`.
     """
     input = as_tensor_variable(input)
-    if op:
-        if dtype not in (None, "float64"):
-            raise NotImplementedError(
-                "The Mean op does not support the dtype argument, "
-                "and will always use float64. If you want to specify "
-                "the dtype, call tensor.mean(..., op=False).",
-                dtype,
-            )
-        if acc_dtype not in (None, "float64"):
-            raise NotImplementedError(
-                "The Mean op does not support the acc_dtype argument, "
-                "and will always use float64. If you want to specify "
-                "acc_dtype, call tensor.mean(..., op=False).",
-                dtype,
-            )
-        out = Mean(axis)(input)
-        if keepdims:
-            out = makeKeepDims(input, out, axis)
-        return out
 
     if dtype is not None:
         # The summation will be done with the specified dtype.

tests/link/numba/test_elemwise.py

@@ -16,7 +16,7 @@
 from pytensor.graph.basic import Constant
 from pytensor.graph.fg import FunctionGraph
 from pytensor.tensor.elemwise import DimShuffle
-from pytensor.tensor.math import All, Any, Max, Mean, Min, Prod, ProdWithoutZeros, Sum
+from pytensor.tensor.math import All, Any, Max, Min, Prod, ProdWithoutZeros, Sum
 from pytensor.tensor.special import LogSoftmax, Softmax, SoftmaxGrad
 from tests.link.numba.test_basic import (
     compare_numba_and_py,
@@ -256,18 +256,6 @@ def test_Dimshuffle_non_contiguous():
             0,
             set_test_value(pt.vector(), np.arange(3, dtype=config.floatX)),
         ),
-        (
-            lambda x, axis=None, dtype=None, acc_dtype=None: Mean(axis)(x),
-            0,
-            set_test_value(pt.vector(), np.arange(3, dtype=config.floatX)),
-        ),
-        (
-            lambda x, axis=None, dtype=None, acc_dtype=None: Mean(axis)(x),
-            0,
-            set_test_value(
-                pt.matrix(), np.arange(3 * 2, dtype=config.floatX).reshape((3, 2))
-            ),
-        ),
         (
             lambda x, axis=None, dtype=None, acc_dtype=None: Sum(
                 axis=axis, dtype=dtype, acc_dtype=acc_dtype

tests/scalar/test_basic.py

@@ -43,7 +43,6 @@
     log1p,
     log2,
     log10,
-    mean,
     mul,
     neg,
     neq,
@@ -58,7 +57,7 @@
     true_div,
     uint8,
 )
-from pytensor.tensor.type import fscalar, imatrix, iscalar, matrix
+from pytensor.tensor.type import fscalar, imatrix, matrix
 from tests.link.test_link import make_function
 
 
@@ -521,34 +520,6 @@ def test_constant():
     assert c.dtype == "float32"
 
 
-@pytest.mark.parametrize("mode", [Mode("py"), Mode("cvm")])
-def test_mean(mode):
-    a = iscalar("a")
-    b = iscalar("b")
-    z = mean(a, b)
-    z_fn = pytensor.function([a, b], z, mode=mode)
-    res = z_fn(1, 1)
-    assert np.allclose(res, 1.0)
-
-    a = fscalar("a")
-    b = fscalar("b")
-    c = fscalar("c")
-
-    z = mean(a, b, c)
-
-    z_fn = pytensor.function([a, b, c], pytensor.grad(z, [a]), mode=mode)
-    res = z_fn(3, 4, 5)
-    assert np.allclose(res, 1 / 3)
-
-    z_fn = pytensor.function([a, b, c], pytensor.grad(z, [b]), mode=mode)
-    res = z_fn(3, 4, 5)
-    assert np.allclose(res, 1 / 3)
-
-    z = mean()
-    z_fn = pytensor.function([], z, mode=mode)
-    assert z_fn() == 0
-
-
 def test_shape():
     a = float32("a")
     assert isinstance(a.type, ScalarType)

tests/tensor/test_math.py

@@ -40,7 +40,6 @@
     Argmax,
     Dot,
     Max,
-    Mean,
     Prod,
     ProdWithoutZeros,
     Sum,
@@ -2587,15 +2586,6 @@ def test_mod_compile():
 
 
 class TestInferShape(utt.InferShapeTester):
-    def test_Mean(self):
-        adtens3 = dtensor3()
-        adtens3_val = random(3, 4, 5)
-        aiscal_val = 2
-        self._compile_and_check([adtens3], [Mean(None)(adtens3)], [adtens3_val], Mean)
-        self._compile_and_check(
-            [adtens3], [Mean(aiscal_val)(adtens3)], [adtens3_val], Mean
-        )
-
     def test_Max(self):
         adtens3 = dtensor3()
         adtens3_val = random(4, 5, 3)