addressing some comments (6)

Author: normen662

fdb-extensions/src/main/java/com/apple/foundationdb/async/hnsw/StorageAdapter.java

@@ -24,6 +24,7 @@
 import com.apple.foundationdb.Transaction;
 import com.apple.foundationdb.async.rabitq.EncodedRealVector;
 import com.apple.foundationdb.linear.DoubleRealVector;
+import com.apple.foundationdb.linear.FloatRealVector;
 import com.apple.foundationdb.linear.HalfRealVector;
 import com.apple.foundationdb.linear.RealVector;
 import com.apple.foundationdb.linear.VectorType;
@@ -278,6 +279,8 @@ static RealVector vectorFromBytes(@Nonnull final HNSW.Config config, @Nonnull fi
         switch (fromVectorTypeOrdinal(vectorTypeOrdinal)) {
             case HALF:
                 return HalfRealVector.fromBytes(vectorBytes);
+            case SINGLE:
+                return FloatRealVector.fromBytes(vectorBytes);
             case DOUBLE:
                 return DoubleRealVector.fromBytes(vectorBytes);
             case RABITQ:

fdb-extensions/src/main/java/com/apple/foundationdb/async/rabitq/EncodedRealVector.java

@@ -21,6 +21,7 @@
 package com.apple.foundationdb.async.rabitq;
 
 import com.apple.foundationdb.linear.DoubleRealVector;
+import com.apple.foundationdb.linear.FloatRealVector;
 import com.apple.foundationdb.linear.HalfRealVector;
 import com.apple.foundationdb.linear.RealVector;
 import com.apple.foundationdb.linear.VectorType;
@@ -45,8 +46,14 @@ public class EncodedRealVector implements RealVector {
 
     @Nonnull
     private final Supplier<Integer> hashCodeSupplier;
+    @Nonnull
     private final Supplier<double[]> dataSupplier;
+    @Nonnull
     private final Supplier<byte[]> rawDataSupplier;
+    @Nonnull
+    private final Supplier<HalfRealVector> toHalfRealVectorSupplier;
+    @Nonnull
+    private final Supplier<FloatRealVector> toFloatRealVectorSupplier;
 
     public EncodedRealVector(final int numExBits, @Nonnull final int[] encoded, final double fAddEx, final double fRescaleEx,
                              final double fErrorEx) {
@@ -56,8 +63,10 @@ public EncodedRealVector(final int numExBits, @Nonnull final int[] encoded, fina
         this.fErrorEx = fErrorEx;
 
         this.hashCodeSupplier = Suppliers.memoize(this::computeHashCode);
-        this.dataSupplier = Suppliers.memoize(() -> computeData(numExBits));
         this.rawDataSupplier = Suppliers.memoize(() -> computeRawData(numExBits));
+        this.dataSupplier = Suppliers.memoize(() -> computeData(numExBits));
+        this.toHalfRealVectorSupplier = Suppliers.memoize(this::computeHalfRealVector);
+        this.toFloatRealVectorSupplier = Suppliers.memoize(this::computeFloatRealVector);
     }
 
     @Nonnull
@@ -214,9 +223,25 @@ private void packEncodedComponents(final int numExBits, @Nonnull final ByteBuffe
     @Nonnull
     @Override
     public HalfRealVector toHalfRealVector() {
+        return toHalfRealVectorSupplier.get();
+    }
+
+    @Nonnull
+    private HalfRealVector computeHalfRealVector() {
         return new HalfRealVector(getData());
     }
 
+    @Nonnull
+    @Override
+    public FloatRealVector toFloatRealVector() {
+        return toFloatRealVectorSupplier.get();
+    }
+
+    @Nonnull
+    private FloatRealVector computeFloatRealVector() {
+        return new FloatRealVector(getData());
+    }
+
     @Nonnull
     @Override
     public DoubleRealVector toDoubleRealVector() {

fdb-extensions/src/main/java/com/apple/foundationdb/async/rabitq/RaBitQuantizer.java

@@ -91,7 +91,6 @@ Result encodeInternal(@Nonnull final RealVector data) {
             totalCode[i] = signedCode[i] + (sgn << numExBits);
         }
 
-        // 4) cb = -(2^b - 0.5), and xuCb = signedShift + cb
         final double cb = -(((1 << numExBits) - 0.5));
         double[] xuCbData = new double[dims];
         for (int i = 0; i < dims; i++) {

fdb-extensions/src/main/java/com/apple/foundationdb/linear/ColumnMajorRealMatrix.java

@@ -108,6 +108,24 @@ public RealMatrix subMatrix(final int startRow, final int lengthRow, final int s
         return new ColumnMajorRealMatrix(subData);
     }
 
+    @Nonnull
+    @Override
+    public RowMajorRealMatrix toRowMajor() {
+        return new RowMajorRealMatrix(transpose().getData());
+    }
+
+    @Nonnull
+    @Override
+    public ColumnMajorRealMatrix toColumnMajor() {
+        return this;
+    }
+
+    @Nonnull
+    @Override
+    public RealMatrix quickTranspose() {
+        return new RowMajorRealMatrix(data);
+    }
+
     @Override
     public final boolean equals(final Object o) {
         if (o instanceof ColumnMajorRealMatrix) {

fdb-extensions/src/main/java/com/apple/foundationdb/linear/DoubleRealVector.java

@@ -35,14 +35,17 @@
 public class DoubleRealVector extends AbstractRealVector {
     @Nonnull
     private final Supplier<HalfRealVector> toHalfVectorSupplier;
+    @Nonnull
+    private final Supplier<FloatRealVector> toFloatVectorSupplier;
 
     public DoubleRealVector(@Nonnull final Double[] doubleData) {
         this(computeDoubleData(doubleData));
     }
 
     public DoubleRealVector(@Nonnull final double[] data) {
         super(data);
-        this.toHalfVectorSupplier = Suppliers.memoize(this::computeHalfVector);
+        this.toHalfVectorSupplier = Suppliers.memoize(this::computeHalfRealVector);
+        this.toFloatVectorSupplier = Suppliers.memoize(this::computeFloatRealVector);
     }
 
     public DoubleRealVector(@Nonnull final int[] intData) {
@@ -59,15 +62,26 @@ public HalfRealVector toHalfRealVector() {
         return toHalfVectorSupplier.get();
     }
 
+    @Nonnull
+    public HalfRealVector computeHalfRealVector() {
+        return new HalfRealVector(data);
+    }
+
     @Nonnull
     @Override
-    public DoubleRealVector toDoubleRealVector() {
-        return this;
+    public FloatRealVector toFloatRealVector() {
+        return toFloatVectorSupplier.get();
     }
 
     @Nonnull
-    public HalfRealVector computeHalfVector() {
-        return new HalfRealVector(data);
+    private FloatRealVector computeFloatRealVector() {
+        return new FloatRealVector(data);
+    }
+
+    @Nonnull
+    @Override
+    public DoubleRealVector toDoubleRealVector() {
+        return this;
     }
 
     @Nonnull

fdb-extensions/src/main/java/com/apple/foundationdb/linear/FloatRealVector.java

@@ -0,0 +1,143 @@
+/*
+ * HalfRealVector.java
+ *
+ * This source file is part of the FoundationDB open source project
+ *
+ * Copyright 2015-2025 Apple Inc. and the FoundationDB project authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.apple.foundationdb.linear;
+
+import com.apple.foundationdb.half.Half;
+import com.google.common.base.Suppliers;
+import com.google.common.base.Verify;
+
+import javax.annotation.Nonnull;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.function.Supplier;
+
+/**
+ * A vector class encoding a vector over float components.
+ */
+public class FloatRealVector extends AbstractRealVector {
+    @Nonnull
+    private final Supplier<HalfRealVector> toHalfRealVectorSupplier;
+
+    public FloatRealVector(@Nonnull final float[] floatData) {
+        this(computeDoubleData(floatData));
+    }
+
+    public FloatRealVector(@Nonnull final double[] data) {
+        super(truncateDoubleData(data));
+        this.toHalfRealVectorSupplier = Suppliers.memoize(this::computeHalfRealVector);
+    }
+
+    public FloatRealVector(@Nonnull final int[] intData) {
+        this(fromInts(intData));
+    }
+
+    public FloatRealVector(@Nonnull final long[] longData) {
+        this(fromLongs(longData));
+    }
+
+    @Nonnull
+    @Override
+    public HalfRealVector toHalfRealVector() {
+        return toHalfRealVectorSupplier.get();
+    }
+
+    @Nonnull
+    public HalfRealVector computeHalfRealVector() {
+        return new HalfRealVector(data);
+    }
+
+    @Nonnull
+    @Override
+    public FloatRealVector toFloatRealVector() {
+        return this;
+    }
+
+    @Nonnull
+    @Override
+    public DoubleRealVector toDoubleRealVector() {
+        return new DoubleRealVector(data);
+    }
+
+    @Nonnull
+    @Override
+    public RealVector withData(@Nonnull final double[] data) {
+        return new FloatRealVector(data);
+    }
+
+    /**
+     * Converts this {@link RealVector} of single precision floating-point numbers into a byte array.
+     * <p>
+     * This method iterates through the input vector, converting each {@link Half} element into its 16-bit short
+     * representation. It then serializes this short into two bytes, placing them sequentially into the resulting byte
+     * array. The final array's length will be {@code 2 * vector.size()}.
+     * @return a new byte array representing the serialized vector data. This array is never null.
+     */
+    @Nonnull
+    @Override
+    protected byte[] computeRawData() {
+        final byte[] vectorBytes = new byte[1 + 4 * getNumDimensions()];
+        final ByteBuffer buffer = ByteBuffer.wrap(vectorBytes).order(ByteOrder.BIG_ENDIAN);
+        buffer.put((byte)VectorType.SINGLE.ordinal());
+        for (int i = 0; i < getNumDimensions(); i ++) {
+            buffer.putFloat((float)data[i]);
+        }
+        return vectorBytes;
+    }
+
+    @Nonnull
+    private static double[] computeDoubleData(@Nonnull float[] floatData) {
+        double[] result = new double[floatData.length];
+        for (int i = 0; i < floatData.length; i++) {
+            result[i] = floatData[i];
+        }
+        return result;
+    }
+
+    @Nonnull
+    private static double[] truncateDoubleData(@Nonnull double[] doubleData) {
+        double[] result = new double[doubleData.length];
+        for (int i = 0; i < doubleData.length; i++) {
+            result[i] = (float)doubleData[i];
+        }
+        return result;
+    }
+
+    /**
+     * Creates a {@link FloatRealVector} from a byte array.
+     * <p>
+     * This method interprets the input byte array as a sequence of 16-bit half-precision floating-point numbers. Each
+     * consecutive pair of bytes is converted into a {@code Half} value, which then becomes a component of the resulting
+     * vector.
+     * @param vectorBytes the non-null byte array to convert
+     * @return a new {@link FloatRealVector} instance created from the byte array
+     */
+    @Nonnull
+    public static FloatRealVector fromBytes(@Nonnull final byte[] vectorBytes) {
+        final ByteBuffer buffer = ByteBuffer.wrap(vectorBytes).order(ByteOrder.BIG_ENDIAN);
+        Verify.verify(buffer.get() == VectorType.SINGLE.ordinal());
+        final int numDimensions = vectorBytes.length >> 2;
+        final double[] vectorComponents = new double[numDimensions];
+        for (int i = 0; i < numDimensions; i ++) {
+            vectorComponents[i] = buffer.getFloat();
+        }
+        return new FloatRealVector(vectorComponents);
+    }
+}

fdb-extensions/src/main/java/com/apple/foundationdb/linear/HalfRealVector.java

@@ -56,12 +56,13 @@ public HalfRealVector toHalfRealVector() {
 
     @Nonnull
     @Override
-    public DoubleRealVector toDoubleRealVector() {
-        return new DoubleRealVector(data);
+    public FloatRealVector toFloatRealVector() {
+        return new FloatRealVector(data);
     }
 
     @Nonnull
-    public DoubleRealVector computeDoubleVector() {
+    @Override
+    public DoubleRealVector toDoubleRealVector() {
         return new DoubleRealVector(data);
     }
 

fdb-extensions/src/main/java/com/apple/foundationdb/linear/MatrixHelpers.java

@@ -0,0 +1,44 @@
+/*
+ * MatrixHelpers.java
+ *
+ * This source file is part of the FoundationDB open source project
+ *
+ * Copyright 2015-2025 Apple Inc. and the FoundationDB project authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.apple.foundationdb.linear;
+
+import javax.annotation.Nonnull;
+import java.util.Random;
+
+public class MatrixHelpers {
+    @Nonnull
+    public static RealMatrix randomOrthogonalMatrix(@Nonnull final Random random, final int dimension) {
+        return QRDecomposition.decomposeMatrix(randomGaussianMatrix(random, dimension, dimension)).getQ();
+    }
+
+    @Nonnull
+    public static RealMatrix randomGaussianMatrix(@Nonnull final Random random,
+                                                  final int rowDimension,
+                                                  final int columnDimension) {
+        final double[][] resultMatrix = new double[rowDimension][columnDimension];
+        for (int row = 0; row < rowDimension; row++) {
+            for (int column = 0; column < columnDimension; column++) {
+                resultMatrix[row][column] = random.nextGaussian();
+            }
+        }
+        return new RowMajorRealMatrix(resultMatrix);
+    }
+}

fdb-extensions/src/main/java/com/apple/foundationdb/linear/Metric.java

@@ -142,4 +142,9 @@ public double distance(@Nonnull final double[] vectorData1, @Nonnull final doubl
     public double distance(@Nonnull RealVector vector1, @Nonnull RealVector vector2) {
         return distance(vector1.getData(), vector2.getData());
     }
+
+    @Override
+    public String toString() {
+        return metricDefinition.toString();
+    }
 }