Merge branch 'master' into v0.70-tflite

Author: Oceania2018

src/TensorFlowNET.Core/Gradients/array_grad.cs

@@ -223,6 +223,22 @@ public static Tensor[] _ReshapeGrad(Operation op, Tensor[] grads)
             return new Tensor[] { array_ops.reshape(grads[0], array_ops.shape(op.inputs[0])), null };
         }
 
+        [RegisterGradient("Pack")]
+        public static Tensor[] _PackGrad(Operation op, Tensor[] grads)
+        {
+            var grad = grads[0];
+            var num = op.get_attr<int>("N");
+            var axis = op.get_attr<int>("axis");
+            return array_ops.unstack(grad, num: num, axis: axis);
+        }
+
+        [RegisterGradient("Unpack")]
+        public static Tensor[] _UnpackGrad(Operation op, Tensor[] grads)
+        {
+            var axis = op.get_attr<int>("axis");
+            return new[] { array_ops.stack(grads, axis: axis) };
+        }
+
         [RegisterGradient("Pad")]
         public static Tensor[] _PadGrad(Operation op, Tensor[] grads)
         {

src/TensorFlowNET.Core/IO/MemmappedFileSystem.cs

@@ -0,0 +1,70 @@
+/*****************************************************************************
+   Copyright 2021 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+******************************************************************************/
+
+using System;
+using System.IO;
+using System.IO.MemoryMappedFiles;
+using System.Linq;
+using Tensorflow;
+
+namespace Tensorflow.IO
+{
+    public class MemmappedFileSystem
+    {
+        public const string MEMMAPPED_PACKAGE_DEFAULT_NAME = "memmapped_package://.";
+
+        private MemoryMappedFile _mmapFile;
+        private MemmappedFileSystemDirectory _directory;
+
+        public MemmappedFileSystem(string path)
+        {
+            using (var stream = File.OpenRead(path))
+            {
+                // Read the offset for the directory
+                var offsetData = new byte[sizeof(ulong)];
+                stream.Seek(-sizeof(ulong), SeekOrigin.End);
+                stream.Read(offsetData, 0, sizeof(ulong));
+                var offset = BitConverter.ToUInt64(offsetData, 0);
+
+                var dirLength = stream.Length - (long) offset - sizeof(ulong);
+                if (dirLength < 0)
+                {
+                    throw new InvalidDataException("Malformed mmapped filesystem!");
+                }
+
+                var dirData = new byte[dirLength];
+
+                stream.Seek((long) offset, SeekOrigin.Begin);
+                stream.Read(dirData, 0, (int) dirLength);
+
+                _directory = MemmappedFileSystemDirectory.Parser.ParseFrom(dirData);
+            }
+
+            _mmapFile = MemoryMappedFile.CreateFromFile(path, FileMode.Open);
+        }
+
+        public Stream OpenMemmapped(string filename)
+        {
+            var entry = _directory.Element.FirstOrDefault(x => x.Name == filename);
+            if (entry == null)
+            {
+                throw new FileNotFoundException($"Missing memmaped file entry: {filename}");
+            }
+
+            return _mmapFile.CreateViewStream((long) entry.Offset, (long) entry.Length);
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/array_ops.cs

@@ -494,20 +494,12 @@ public static Tensor stack(Tensor[] values, int axis = 0, string name = "stack")
                 return ops.convert_to_tensor(values, name: name);
             }
 
-            var value_shape = ops.convert_to_tensor(values[0], name: name).shape;
-
             return gen_array_ops.pack(values, axis: axis, name: name);
         }
 
         public static Tensor[] unstack(Tensor value, int? num = null, int axis = 0, string name = "unstack")
         {
-            if (num == null)
-            {
-                value = ops.convert_to_tensor(value);
-                var value_shape = value.shape;
-                num = (int)value_shape.dims[axis];
-            }
-
+            num = num ?? value.shape.as_int_list()[axis];
             return gen_array_ops.unpack(value, num: num.Value, axis: axis, name: name);
         }
 

src/TensorFlowNET.Core/Operations/gen_array_ops.cs

@@ -265,10 +265,8 @@ public static (Tensor, Tensor) unique(Tensor x, TF_DataType out_idx = TF_DataTyp
         }
 
         public static Tensor[] unpack(Tensor value, int num, int axis = 0, string name = null)
-        {
-            var _op = tf.OpDefLib._apply_op_helper("Unpack", name, new { value, num, axis });
-            return _op.outputs;
-        }
+            => tf.Context.ExecuteOp("Unpack", name, new ExecuteOpArgs(value, num)
+                    .SetAttributes(new { axis }));
 
         public static Tensor where(Tensor condition, string name = null)
         {