Feat : Add Shape Test + Compution indexes by 1D array index

Author: dotchris90

src/NumSharp.Core/Shape.cs

@@ -8,6 +8,7 @@ public partial class Shape
     {
         private readonly IReadOnlyList<int> shape;
         private readonly IReadOnlyList<int> dimOffset;
+        private readonly int dimOffsetTotal;
 
         public int Size
         {
@@ -37,6 +38,7 @@ public Shape(params int[] shape)
             {
                 temp[i - 1] = temp[i] * shape[i];
             }
+            
             dimOffset = temp;
         }
 
@@ -67,6 +69,30 @@ public int GetIndexInShape(params int[] select)
 
             return idx;
         }
+        public int[] GetDimIndexOutShape(int select)
+        {
+            int[] dimIndexes = null;
+            if (this.dimOffset.Count == 1)
+                dimIndexes = new int[] {select};
+            else if (this.dimOffset.Count == 2) 
+            {
+                dimIndexes = new int[dimOffset.Count];
+
+                int remaining = select;
+
+                for (int idx = 0;idx < dimOffset.Count;idx++)
+                {
+                    dimIndexes[idx] = remaining / dimOffset[idx];
+                    remaining -= (dimIndexes[idx] * dimOffset[idx] );
+                }    
+            }
+            else 
+            {
+                throw new IncorrectShapeException();
+            }
+
+            return dimIndexes;
+        }
 
         public int UniShape => shape[0];
 

test/NumSharp.UnitTest/Shape.Test.cs

@@ -0,0 +1,27 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using NumSharp.Core.Extensions;
+using System.Linq;
+using NumSharp.Core;
+
+namespace NumSharp.UnitTest
+{
+    [TestClass]
+    public class NDStorageTest
+    {
+        [TestMethod]
+        public void Index()
+        {
+            var shape0 = new Shape(4,3);
+
+            int idx0 = shape0.GetIndexInShape(2,1);
+            int[] idx00 = shape0.GetDimIndexOutShape(idx0);
+
+            Assert.IsTrue(idx00[0] == 2);
+            Assert.IsTrue(idx00[1] == 1);
+
+        }
+    }
+}