Fixed ambiguous overloads.

src/TensorFlowNET.Core/Tensors/TensorShape.cs

@@ -55,17 +55,6 @@ namespace Tensorflow
             }
         }
 
-        public TensorShape(params int[] dims)
-        {
-            switch (dims.Length)
-            {
-                case 0: shape = new Shape(new int[0]); break;
-                case 1: shape = Shape.Vector((int) dims[0]); break;
-                case 2: shape = Shape.Matrix(dims[0], dims[1]); break;
-                default: shape = new Shape(dims); break;
-            }
-        }
-
         /// <summary>
         ///     An overload that can accept <see cref="Binding.None"/>.
         /// </summary>

src/TensorFlowNET.Core/tensorflow.cs

@@ -63,7 +63,7 @@ namespace Tensorflow
             return gen_array_ops.placeholder(dtype, shape, name);
         }
 
-        public unsafe Tensor placeholder(TF_DataType dtype, object[] shape = null, string name = null)
+        public unsafe Tensor placeholder(TF_DataType dtype, object[] shape, string name = null)
         {
             return placeholder(dtype, new TensorShape(shape), name);
         }