np.average #894

Author: Oceania2018

src/TensorFlowNET.Core/NumPy/Implementation/NumPyImpl.Statistics.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+
+namespace Tensorflow.NumPy
+{
+    public partial class NumPyImpl
+    {
+        public NDArray average(NDArray a, int axis = -1, NDArray? weights = null, bool returned = false)
+        {
+            var dtype = NumPyUtils.GetResultType(a.dtype, np.float64);
+            if(weights is null)
+            {
+                var tensorA = math_ops.cast(a, dtype);
+                var nd = math_ops.reduce_mean(tensorA, axis);
+                return new NDArray(nd);
+            }
+            else
+            {
+                var tensorW = math_ops.cast(weights, dtype);
+                if(a.rank != weights.rank)
+                {
+                    var weights_sum = math_ops.reduce_sum(tensorW);
+                    var axes = ops.convert_to_tensor(new[,] { { axis }, { 0 } });
+                    var avg = math_ops.tensordot(a, weights, axes) / weights_sum;
+                }
+                
+                throw new NotImplementedException("");
+            }
+        }
+    }
+}

src/TensorFlowNET.Core/NumPy/NumPy.Statistics.cs

@@ -14,5 +14,9 @@ public partial class np
 
         [AutoNumPy]
         public static NDArray amax(NDArray x, int axis = 0) => new NDArray(tf.math.argmax(x, axis));
+
+        [AutoNumPy]
+        public static NDArray average(NDArray a, int axis = -1, NDArray? weights = null, bool returned = false)
+            => tf.numpy.average(a, axis: axis, weights: weights, returned: returned);
     }
 }

src/TensorFlowNET.Core/NumPy/NumPyUtils.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Text;
+
+namespace Tensorflow.NumPy
+{
+    internal class NumPyUtils
+    {
+        public static TF_DataType GetResultType(params TF_DataType[] dtypes)
+        {
+            var resultDType = dtypes[0];
+            for(int i = 1; i < dtypes.Length; i++)
+            {
+                if (dtypes[i].get_datatype_size() > resultDType.get_datatype_size())
+                    resultDType = dtypes[i];
+            }
+            return resultDType;
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/math_ops.cs

@@ -929,6 +929,72 @@ Tensor _tensordot_reshape(Tensor a, int[] axes, bool flipped = false)
             throw new NotImplementedException("tensordot");
         }
 
+        public static Tensor tensordot(Tensor x, Tensor y, Tensor axes, string name = null)
+        {
+            Tensor _tensordot_reshape(Tensor a, int[] axes, bool flipped = false)
+            {
+                if (a.shape.IsFullyDefined && isinstance(axes, (typeof(List<object>), typeof(Tuple))))
+                {
+                    var shape_a = a.shape.dims;
+
+                    // axes
+                    int iter = 0;
+                    foreach (int i in axes)
+                    {
+                        if (i >= 0)
+                            axes[0 + iter] = i;
+                        else
+                            axes[0 + iter] = i + len(shape_a);
+                        iter++;
+                    }
+
+                    // free
+                    int[] free = { };
+                    iter = 0;
+                    foreach (int i in Enumerable.Range(0, len(axes)))
+                        if (!Array.Exists(axes, i => i == i))
+                            free[free.Length] = i;
+
+                    // free_dims
+                    int[] free_dims = { };
+                    foreach (int i in free)
+                        free_dims[free_dims.Length] = (int)shape_a[i];
+
+                    int prod_free = (int)np.prod(free_dims);
+
+                    // prod_axes
+                    int[] prod_axes_pre = { };
+                    foreach (int i in axes)
+                        prod_axes_pre[prod_axes_pre.Length] = (int)shape_a[i];
+                    int prod_axes = (int)np.prod(prod_axes_pre);
+
+                    // perm
+                    Tensor perm;
+                    if (flipped)
+                        perm = ops.convert_to_tensor(list(free)) + ops.convert_to_tensor(free);
+                    else
+                        perm = ops.convert_to_tensor(list(free)) + ops.convert_to_tensor(free)
+                                                                 + ops.convert_to_tensor(list(axes));
+
+                    // new_shape
+                    Shape new_shape;
+                    if (flipped)
+                        new_shape = new Shape(new int[] { prod_axes, prod_free });
+                    else
+                        new_shape = new Shape(new int[] { prod_free, prod_axes });
+                }
+
+                throw new NotImplementedException("_tensordot_reshape");
+            }
+
+            return tf_with(ops.name_scope(name, "Tensordot", new { x, y, axes }), scope =>
+            {
+                name = scope;
+                var (a_axes, b_axes) = (axes[0], axes[1]);
+                return x;
+            });
+        }
+
         public static Tensor truediv(Tensor x, Tensor y, string name = null)
             => _truediv_python3(x, y, name);
 

src/TensorFlowNET.Core/Tensors/Tensor.cs

@@ -78,7 +78,7 @@ public partial class Tensor : DisposableObject,
         /// <summary>
         ///     The name of the device on which this tensor will be produced, or null.
         /// </summary>
-        public virtual string Device => op.Device;
+        public virtual string Device => op?.Device;
         public long[] dims => shape.dims;
 
         /// <summary>

test/TensorFlowNET.UnitTest/NumPy/Statistics.Test.cs

@@ -0,0 +1,32 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Tensorflow;
+using Tensorflow.NumPy;
+
+namespace TensorFlowNET.UnitTest.NumPy
+{
+    /// <summary>
+    /// https://numpy.org/doc/stable/reference/routines.statistics.html
+    /// </summary>
+    [TestClass]
+    public class StatisticsTest : EagerModeTestBase
+    {
+        [TestMethod]
+        public void average()
+        {
+            var data = np.arange(1, 5);
+            var avg = np.average(data);
+            Assert.AreEqual(avg, 2.5);
+
+            data = np.arange(6).reshape((3, 2));
+            avg = np.average(data, axis: 1);
+            assertAllEqual(avg.ToArray<double>(), new[] { 0.5, 2.5, 4.5 });
+
+            // avg = np.average(data, axis: 1, weights: new[] { 1.0 / 4, 3.0 / 4 });
+            // assertAllEqual(avg.ToArray<double>(), new[] { 0.75, 2.75, 4.75 });
+        }
+    }
+}