argsort fix.

Author: Oceania2018

src/TensorFlowNET.Core/NumPy/Axis.cs

@@ -55,6 +55,12 @@ public static implicit operator Axis(Shape axis)
         public static implicit operator Tensor(Axis axis)
             => constant_op.constant(axis);
 
+        public static bool operator ==(Axis left, int right)
+            => left.IsScalar && left[0] == right;
+
+        public static bool operator !=(Axis left, int right)
+            => !(left == right);
+
         public override string ToString()
             => IsScalar ? $"{axis[0]}" : $"({string.Join(", ", axis)})";
     }

src/TensorFlowNET.Core/Operations/sort_ops.cs

@@ -14,7 +14,7 @@ You may obtain a copy of the License at
    limitations under the License.
 ******************************************************************************/
 
-using Tensorflow.Operations;
+using System;
 using static Tensorflow.Binding;
 
 namespace Tensorflow
@@ -26,8 +26,21 @@ public static Tensor argsort(Tensor values, Axis axis = null, string direction =
             axis = axis ?? new Axis(-1);
             var k = array_ops.shape(values)[axis];
             values = -values;
+            var static_rank = values.shape.ndim;
+            var top_k_input = values;
+            if (axis == -1 || axis + 1 == values.shape.ndim)
+            {
+            }
+            else
+            {
+                if (axis == 0 && static_rank == 2)
+                    top_k_input = array_ops.transpose(values, new[] { 1, 0 });
+                else
+                    throw new NotImplementedException("");
+            }
+
             var (_, indices) = tf.Context.ExecuteOp("TopKV2", name,
-                new ExecuteOpArgs(values, k).SetAttributes(new
+                new ExecuteOpArgs(top_k_input, k).SetAttributes(new
                 {
                     sorted = true
                 }));