using Microsoft.VisualStudio.TestTools.UnitTesting;
using static Tensorflow.Binding;

namespace TensorFlowNET.UnitTest.ManagedAPI
{
    [TestClass]
    public class GradientTest
    {
        [TestMethod]
        public void GradientFloatTest()
        {
            var x = tf.Variable(3.0, dtype: tf.float32);
            using var tape = tf.GradientTape();
            var y = tf.square(x);
            var y_grad = tape.gradient(y, x);
            Assert.AreEqual(9.0f, (float)y);
        }

        [TestMethod]
        public void GradientDefaultTest()
        {
            var x = tf.Variable(3.0);
            using var tape = tf.GradientTape();
            var y = tf.square(x);
            var y_grad = tape.gradient(y, x);
            Assert.AreEqual(9.0, (double)y);
        }

        [TestMethod]
        public void GradientDoubleTest()
        {
            var x = tf.Variable(3.0, dtype: tf.float64);
            using var tape = tf.GradientTape();
            var y = tf.square(x);
            var y_grad = tape.gradient(y, x);
            Assert.AreEqual(9.0, (double)y);
        }

        [TestMethod]
        public void GradientOperatorMulTest()
        {
            var x = tf.constant(0f);
            var w = tf.Variable(new float[] { 1, 1 });
            using var gt = tf.GradientTape();
            var y = x * w;
            var gr = gt.gradient(y, w);
            Assert.AreEqual(new float[] { 0, 0 }, gr.numpy());
        }
    }
}