Added BCE loss.

Author: interesaaat

TorchSharp/NN/LossFunction.cs

@@ -9,6 +9,14 @@ namespace TorchSharp.NN
     /// </summary>
     public class LossFunction
     {
+        [DllImport("libTorchSharp")]
+        extern static IntPtr THSNN_lossBCE(IntPtr srct, IntPtr trgt, IntPtr wgt, long reduction);
+
+        public static ITorchTensor<float> BCE<T, U>(ITorchTensor<T> src, ITorchTensor<U> target, ITorchTensor<U> weigths = null, Reduction reduction = Reduction.Mean)
+        {
+            return new FloatTensor(THSNN_lossBCE(src.Handle, target.Handle, weigths?.Handle ?? IntPtr.Zero, (long)reduction));
+        }
+
         [DllImport("libTorchSharp")]
         extern static IntPtr THSNN_lossMSE(IntPtr srct, IntPtr trgt, long reduction);
 
@@ -18,11 +26,11 @@ public static ITorchTensor<float> MSE<T>(ITorchTensor<T> src, ITorchTensor<T> ta
         }
 
         [DllImport("libTorchSharp")]
-        extern static IntPtr THSNN_lossNLL(IntPtr srct, IntPtr trgt, long reduction);
+        extern static IntPtr THSNN_lossNLL(IntPtr srct, IntPtr trgt, IntPtr wgt, long reduction);
 
-        public static ITorchTensor<float> NLL<T, U>(ITorchTensor<T> src, ITorchTensor<U> target, Reduction reduction = Reduction.Mean)
+        public static ITorchTensor<float> NLL<T, U>(ITorchTensor<T> src, ITorchTensor<U> target, ITorchTensor<U> weigths = null, Reduction reduction = Reduction.Mean)
         {
-            return new FloatTensor(THSNN_lossNLL(src.Handle, target.Handle, (long)reduction));
+            return new FloatTensor(THSNN_lossNLL(src.Handle, target.Handle, weigths?.Handle ?? IntPtr.Zero, (long)reduction));
         }
     }