Add tf.math.erf #738

Author: Oceania2018

src/TensorFlowNET.Core/APIs/tf.math.cs

@@ -23,6 +23,15 @@ public class MathApi
         {
             public Tensor log(Tensor x, string name = null)
                 => gen_math_ops.log(x, name);
+
+            /// <summary>
+            /// Computes the Gauss error function of `x` element-wise.
+            /// </summary>
+            /// <param name="x"></param>
+            /// <param name="name"></param>
+            /// <returns></returns>
+            public Tensor erf(Tensor x, string name = null)
+                => math_ops.erf(x, name);
         }
 
         public Tensor abs(Tensor x, string name = null)

src/TensorFlowNET.Core/Operations/math_ops.cs

@@ -265,6 +265,29 @@ public static Tensor greater_equal<Tx, Ty>(Tx x, Ty y, string name = null)
         public static Tensor equal<Tx, Ty>(Tx x, Ty y, string name = null)
             => gen_math_ops.equal(x, y, name: name);
 
+        /// <summary>
+        /// Computes the Gauss error function of `x` element-wise.
+        /// </summary>
+        /// <param name="x"></param>
+        /// <param name="name"></param>
+        /// <returns></returns>
+        public static Tensor erf(Tensor x, string name = null)
+            => tf.Context.RunInAutoMode2(
+                () => tf.OpDefLib._apply_op_helper("Erf", name, new { x }).output,
+                () => tf.Runner.TFE_FastPathExecute(tf.Context, tf.Context.DeviceName,
+                    "Erf", name,
+                    null,
+                    x).FirstOrDefault(),
+                (op) =>
+                {
+                    var attrs = new object[]
+                    {
+                        "T", op.get_attr<TF_DataType>("T")
+                    };
+                    tf.Runner.RecordGradient("Erf", op.inputs, attrs, op.outputs);
+                },
+                new Tensors(x));
+
         public static Tensor sqrt(Tensor x, string name = null)
             => gen_math_ops.sqrt(x, name: name);
 

test/TensorFlowNET.UnitTest/ManagedAPI/MathApiTest.cs

@@ -48,5 +48,14 @@ public void ReduceSum()
             var x5 = tf.reduce_sum(b, (0, 1));
             Assert.AreEqual(-4.7f, (float)x5);
         }
+
+        [TestMethod]
+        public void Erf()
+        {
+            var erf = tf.math.erf(a, name: "erf");
+            var expected = new float[] { 0.8427007f, -0.5204999f, 0.99999845f, -0.9970206f, 0f, -1f };
+            var actual = erf.ToArray<float>();
+            Assert.IsTrue(Equal(expected, actual));
+        }
     }
 }