- Add multidimension support to LowMemoryBinarySparseMatrix.

- Update BinarySparseMatrixTest to run test on both implementations.

src/main/java/org/numenta/nupic/util/BitSetMatrix.java

@@ -45,24 +45,13 @@ public BitSetMatrix(int[] dimensions, boolean useColumnMajorOrdering) {
 		this.data = new BitSet(getSize());
 	}
 
-	@Override
-	public Boolean get(int... coordinates) {
-		return get(computeIndex(coordinates));
-	}
-
 	@Override
 	public Boolean get(int index) {
 		return this.data.get(index);
 	}
 
 	@Override
-	public Matrix<Boolean> set(int[] coordinates, Boolean value) {
-		this.data.set(computeIndex(coordinates), value);
-		return this;
-	}
-
-	@Override
-	public FlatMatrix<Boolean> set(int index, Boolean value) {
+	public BitSetMatrix set(int index, Boolean value) {
 		this.data.set(index, value);
 		return this;
 	}

src/main/java/org/numenta/nupic/util/FlatArrayMatrix.java

@@ -44,20 +44,9 @@ public FlatArrayMatrix(int[] dimensions, boolean useColumnMajorOrdering) {
 		this.data = (T[]) new Object[getSize()];
 	}
 
-	@Override
-	public T get(int... indexes) {
-		return get(computeIndex(indexes));
-	}
-
 	@Override
 	public T get(int index) {
-		return data[index];
-	}
-
-	@Override
-	public FlatArrayMatrix<T> set(int[] indexes, T value) {
-		set(computeIndex(indexes), value); 
-		return this;
+		return this.data[index];
 	}
 
 	@Override

src/main/java/org/numenta/nupic/util/FlatMatrixSupport.java

@@ -23,8 +23,6 @@
 package org.numenta.nupic.util;
 
 import java.lang.reflect.Array;
-import java.lang.reflect.ParameterizedType;
-import java.lang.reflect.Type;
 import java.util.Arrays;
 
 /**
@@ -184,6 +182,23 @@ public static String print1DArray(Object aObject) {
         return "[]";
     }
 
+	@Override
+	public abstract T get(int index);
+
+	@Override 
+	public abstract FlatMatrixSupport<T> set(int index, T value);
+
+	@Override
+	public T get(int... indexes) {
+		return get(computeIndex(indexes));
+	}
+
+	@Override
+	public FlatMatrixSupport<T> set(int[] indexes, T value) {
+		set(computeIndex(indexes), value); 
+		return this;
+	}
+
     public int getSize() {
     	return Arrays.stream(this.dimensions).reduce((n,i) -> n*i).getAsInt();
     }
@@ -211,4 +226,5 @@ public int getNumDimensions() {
 	public int[] getDimensionMultiples() {
 		return this.dimensionMultiples;
 	}
+
 }

src/main/java/org/numenta/nupic/util/LowMemorySparseBinaryMatrix.java

@@ -22,10 +22,11 @@
 
 package org.numenta.nupic.util;
 
+import java.lang.reflect.Array;
 import java.util.Arrays;
 
 /**
- * Low Memory implementation of {@link SparseBinaryMatrixSupport} without 
+ * Low Memory implementation of {@link SparseBinaryMatrix} without 
  * a backing array.
  * 
  * @author Jose Luis Martin
@@ -43,17 +44,34 @@ public LowMemorySparseBinaryMatrix(int[] dimensions, boolean useColumnMajorOrder
 	@Override
 	public Object getSlice(int... coordinates) {
 		int[] dimensions = getDimensions();
-		int[] slice = new int[dimensions[1]];
-		for(int j = 0; j < dimensions[1]; j++) {
-			slice[j] = get(coordinates[0], j);
+		// check for valid coordinates
+		if (coordinates.length >= dimensions.length)
+			sliceError(coordinates);
+
+		int sliceDimensionsLength = dimensions.length - coordinates.length;
+		int[] sliceDimensions = (int[]) Array.newInstance(int.class, sliceDimensionsLength);
+
+		for (int i = coordinates.length ; i < dimensions.length; i++) 
+			sliceDimensions[i - coordinates.length] = dimensions[i];
+
+		int[] elementCoordinates = Arrays.copyOf(coordinates, coordinates.length + 1);
+		Object slice = Array.newInstance(int.class, sliceDimensions);
+
+		if (coordinates.length + 1 == dimensions.length) {
+			// last slice 
+
+			for (int i = 0; i < dimensions[coordinates.length]; i++) {
+				elementCoordinates[coordinates.length] = i;
+				Array.set(slice,  i, get(elementCoordinates));
+			}
 		}
-		//Ensure return value is of type Array
-		if(!slice.getClass().isArray()) {
-			throw new IllegalArgumentException(
-					"This method only returns the array holding the specified index: " + 
-							Arrays.toString(coordinates));
+		else {
+			for (int i = 0; i < dimensions[sliceDimensionsLength]; i++) {
+				elementCoordinates[coordinates.length] = i;
+				Array.set(slice, i, getSlice(elementCoordinates));
+			}
 		}
-
+		
 		return slice;
 	}
 
@@ -79,10 +97,8 @@ public void rightVecSumAtNZ(int[] inputVector, int[] results) {
 
 	@Override
 	public LowMemorySparseBinaryMatrix set(int value, int... coordinates) {
-		if (value > 0) {
-			super.set(value, coordinates);
-			updateTrueCounts(coordinates);
-		}
+		super.set(value, coordinates);
+		updateTrueCounts(coordinates);
 
 		return this;
 	}
@@ -96,27 +112,16 @@ public LowMemorySparseBinaryMatrix setForTest(int index, int value) {
 		return this;
 	}
 
+	/**
+	 * Update the true counts for a coordinates.
+	 * @param coordinates
+	 */
 	private void updateTrueCounts(int... coordinates) {
-		int sum = 0;
-
-		for (int j = 0; j < dimensions[1]; j++) {
-			sum += getIntValue(coordinates[0], j);
-		}
-
+		Object slice = getSlice(coordinates[0]);
+		int sum = ArrayUtils.aggregateArray(slice);
 		setTrueCount(coordinates[0],sum);
 	}
 
-	@Override
-	protected int[] values() {
-		int[] dense = new int[getMaxIndex()];
-		for (int i = 0; i <= getMaxIndex(); i++) {
-			dense[i] = get(i);
-		}
-
-		return dense;
-	}
-
-
 	@Override
 	public LowMemorySparseBinaryMatrix set(int index, Object value) {
 		super.set(index, ((Integer) value).intValue());

src/main/java/org/numenta/nupic/util/SparseBinaryMatrix.java

@@ -63,18 +63,16 @@ private void back(int val, int... coordinates) {
      public Object getSlice(int... coordinates) {
 		Object slice = backingArray;
 		for(int i = 0;i < coordinates.length;i++) {
-			slice = Array.get(slice, coordinates[i]);;
+			slice = Array.get(slice, coordinates[i]);
 		}
 		//Ensure return value is of type Array
 		if(!slice.getClass().isArray()) {
-			throw new IllegalArgumentException(
-				"This method only returns the array holding the specified index: " + 
-					Arrays.toString(coordinates));
+			sliceError(coordinates);
 		}
 
 		return slice;
 	}
-    
+
     /**
      * Fills the specified results array with the result of the 
      * matrix vector multiplication.

src/main/java/org/numenta/nupic/util/SparseBinaryMatrixSupport.java

@@ -56,7 +56,18 @@ public SparseBinaryMatrixSupport(int[] dimensions, boolean useColumnMajorOrderin
      * 			an actual value instead of the array holding it.
      */
      public abstract Object getSlice(int... coordinates);
-
+
+     /**
+ 	 * Launch getSlice error, to share it with subclass {@link #getSlice(int...)}
+ 	 * implementations.
+ 	 * @param coordinates
+ 	 */
+ 	protected void sliceError(int... coordinates) {
+ 		throw new IllegalArgumentException(
+ 			"This method only returns the array holding the specified index: " + 
+ 				Arrays.toString(coordinates));
+ 	}
+
     /**
      * Fills the specified results array with the result of the 
      * matrix vector multiplication.

src/test/java/org/numenta/nupic/util/LowMemorySparseBinaryMatrixTest.java

@@ -27,8 +27,9 @@
 import org.junit.Assert;
 
 /**
+ * Test for {@link LowMemorySparseBinaryMatrix}
+ *  
  * @author Jose Luis Martin
- *
  */
 public class LowMemorySparseBinaryMatrixTest {
 

src/test/java/org/numenta/nupic/util/MatrixTest.java

@@ -22,8 +22,12 @@
 
 package org.numenta.nupic.util;
 
-import org.junit.Test;
 import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+
+import org.junit.Test;
 
 /**
  * Generic test for Matrix hirearchy.
@@ -45,6 +49,7 @@ public void testBitSetMatrixSet() {
 		}
 
 		assertArrayEquals(expected, asDense(bsm));
+		assertEquals(Arrays.toString(expected), FlatArrayMatrix.print1DArray(asDense(bsm)));
 	}
 
 	@Test
@@ -56,8 +61,9 @@ public void testFlatArrayMatrixSet() {
 		for (int index : this.indexes) {
 			fam.set(index, 1);
 		}
-		
+
 		assertArrayEquals(expected, asDense(fam));
+		assertEquals(Arrays.toString(expected), FlatArrayMatrix.print1DArray(asDense(fam)));
 	}
 
 	private Object[] asDense(FlatMatrix<?> matrix) {
@@ -67,6 +73,8 @@ private Object[] asDense(FlatMatrix<?> matrix) {
 			dense[i] = matrix.get(i);
 		}
 
+
+
 		return dense;
 	}
 }