Fix #13731 by adding HistogramdFixedWidth in hidden_ops.txt and create the python wrapper (#13781)

* Fix 13731 by adding HistogramdFixedWidth in hidden_ops.txt and create the python wrapper

so that both api compatibility and test utility code in contrib could be
preserved. See https://github.com/tensorflow/tensorflow/pull/13731#issuecomment-337186002
for reference.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add underscore (`_histogram_fixed_width`) in calling gen_math_ops.py

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* clang-format -i histogram_op.cc

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

4 files changed, 16 insertions, 15 deletions

diff --git a/tensorflow/core/kernels/histogram_op.cc b/tensorflow/core/kernels/histogram_op.cc
index c170f172e4..4e035286f6 100644
--- a/tensorflow/core/kernels/histogram_op.cc
+++ b/tensorflow/core/kernels/histogram_op.cc
@@ -74,45 +74,44 @@ struct HistogramFixedWidthFunctor<CPUDevice, T, Tout> {
 template <typename Device, typename T, typename Tout>
 class HistogramFixedWidthOp : public OpKernel {
  public:
-  explicit HistogramFixedWidthOp(OpKernelConstruction* ctx) : OpKernel(ctx) {
-    OP_REQUIRES_OK(ctx, ctx->GetAttr("nbins", &nbins_));
-    OP_REQUIRES(
-        ctx, (nbins_ > 0),
-        errors::InvalidArgument("nbins should be a positive number, but got '",
-                                nbins_, "'"));
-  }
+  explicit HistogramFixedWidthOp(OpKernelConstruction* ctx) : OpKernel(ctx) {}
 
   void Compute(OpKernelContext* ctx) override {
     const Tensor& values_tensor = ctx->input(0);
     const Tensor& value_range_tensor = ctx->input(1);
+    const Tensor& nbins_tensor = ctx->input(2);
 
     OP_REQUIRES(ctx, TensorShapeUtils::IsVector(value_range_tensor.shape()),
                 errors::InvalidArgument("value_range should be a vector."));
     OP_REQUIRES(ctx, (value_range_tensor.shape().num_elements() == 2),
                 errors::InvalidArgument(
                     "value_range should be a vector of 2 elements."));
+    OP_REQUIRES(ctx, TensorShapeUtils::IsScalar(nbins_tensor.shape()),
+                errors::InvalidArgument("nbins should be a scalar."));
 
     const auto values = values_tensor.flat<T>();
     const auto value_range = value_range_tensor.flat<T>();
+    const auto nbins = nbins_tensor.scalar<int32>()();
 
     OP_REQUIRES(
         ctx, (value_range(0) < value_range(1)),
         errors::InvalidArgument("value_range should satisfy value_range[0] < "
                                 "value_range[1], but got '[",
                                 value_range(0), ", ", value_range(1), "]'"));
+    OP_REQUIRES(
+        ctx, (nbins > 0),
+        errors::InvalidArgument("nbins should be a positive number, but got '",
+                                nbins, "'"));
 
     Tensor* out_tensor;
     OP_REQUIRES_OK(ctx,
-                   ctx->allocate_output(0, TensorShape({nbins_}), &out_tensor));
+                   ctx->allocate_output(0, TensorShape({nbins}), &out_tensor));
     auto out = out_tensor->flat<Tout>();
 
     OP_REQUIRES_OK(
         ctx, functor::HistogramFixedWidthFunctor<Device, T, Tout>::Compute(
-                 ctx, values, value_range, nbins_, out));
+                 ctx, values, value_range, nbins, out));
   }
-
- private:
-  int nbins_;
 };
 
 #define REGISTER_KERNELS(type)                                           \
@@ -135,6 +134,7 @@ TF_CALL_REAL_NUMBER_TYPES(REGISTER_KERNELS);
   REGISTER_KERNEL_BUILDER(Name("HistogramFixedWidth")          \
                               .Device(DEVICE_GPU)              \
                               .HostMemory("value_range")       \
+                              .HostMemory("nbins")             \
                               .TypeConstraint<type>("T")       \
                               .TypeConstraint<int32>("dtype"), \
                           HistogramFixedWidthOp<GPUDevice, type, int32>)
diff --git a/tensorflow/core/ops/math_ops.cc b/tensorflow/core/ops/math_ops.cc
index a1c608ee54..61db896c51 100644
--- a/tensorflow/core/ops/math_ops.cc
+++ b/tensorflow/core/ops/math_ops.cc
@@ -2253,8 +2253,8 @@ product: Pairwise cross product of the vectors in `a` and `b`.
 REGISTER_OP("HistogramFixedWidth")
     .Input("values: T")
     .Input("value_range: T")
+    .Input("nbins: int32")
     .Output("out: dtype")
-    .Attr("nbins: int = 100")
     .Attr("T: {int32, int64, float32, float64}")
     .Attr("dtype: {int32, int64} = DT_INT32")
     .SetShapeFn([](InferenceContext* c) {
diff --git a/tensorflow/python/ops/hidden_ops.txt b/tensorflow/python/ops/hidden_ops.txt
index 04dfb5b65d..86bc038e86 100644
--- a/tensorflow/python/ops/hidden_ops.txt
+++ b/tensorflow/python/ops/hidden_ops.txt
@@ -259,6 +259,7 @@ ComplexAbs
 Conj
 FloorDiv
 FloorMod
+HistogramFixedWidth
 Max
 Mean
 Min
diff --git a/tensorflow/python/ops/histogram_ops.py b/tensorflow/python/ops/histogram_ops.py
index 040c3a5ae8..51e4be9343 100644
--- a/tensorflow/python/ops/histogram_ops.py
+++ b/tensorflow/python/ops/histogram_ops.py
@@ -71,5 +71,5 @@ def histogram_fixed_width(values,
   """
   with ops.name_scope(name, 'histogram_fixed_width',
                       [values, value_range, nbins]) as name:
-    return gen_math_ops.histogram_fixed_width(values, value_range, nbins,
-                                              dtype=dtype, name=name)
+    return gen_math_ops._histogram_fixed_width(values, value_range, nbins,
+                                               dtype=dtype, name=name)