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Accept TDigest bytes with buffered values #704

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Merged
leerho merged 1 commit into from
Dec 19, 2025
Merged

Accept TDigest bytes with buffered values #704

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28 changes: 28 additions & 0 deletions .editorconfig
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@tisonkun tisonkun Dec 19, 2025

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Help IDEA to properly format files without large indentation changes. Can be removed if you don't like to check it into the VCS but IMO it does no harm.

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@tisonkun tisonkun Dec 19, 2025

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Out of the thread: spotless can help in autoformat over checkstyle

See also:

Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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.

root = true

[*]
end_of_line = lf
indent_style = space
insert_final_newline = true
trim_trailing_whitespace = true

[*.java]
indent_size = tab
tab_width = 2
8 changes: 6 additions & 2 deletions src/main/java/org/apache/datasketches/tdigest/TDigestDouble.java
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Original file line number Diff line number Diff line change
Expand Up @@ -426,7 +426,7 @@ public static TDigestDouble heapify(final MemorySegment seg, final boolean isFlo
return new TDigestDouble(reverseMerge, k, value, value, new double[] {value}, new long[] {1}, 1, null);
}
final int numCentroids = posSeg.getInt();
posSeg.getInt(); // unused
final int numBuffered = posSeg.getInt();
final double min;
final double max;
if (isFloat) {
Expand All @@ -444,7 +444,11 @@ public static TDigestDouble heapify(final MemorySegment seg, final boolean isFlo
weights[i] = isFloat ? posSeg.getInt() : posSeg.getLong();
totalWeight += weights[i];
}
return new TDigestDouble(reverseMerge, k, min, max, means, weights, totalWeight, null);
final double[] buffered = new double[numBuffered];
for (int i = 0; i < numBuffered; i++) {
buffered[i] = isFloat ? posSeg.getFloat() : posSeg.getDouble();
}
return new TDigestDouble(reverseMerge, k, min, max, means, weights, totalWeight, buffered);
}

// compatibility with the format of the reference implementation
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76 changes: 45 additions & 31 deletions src/test/java/org/apache/datasketches/tdigest/TDigestCrossLanguageTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,54 +25,68 @@
import static org.apache.datasketches.common.TestUtil.javaPath;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertTrue;

import java.lang.foreign.MemorySegment;
import java.io.IOException;
import java.lang.foreign.MemorySegment;
import java.nio.file.Files;

import org.testng.annotations.Test;

public class TDigestCrossLanguageTest {

@Test(groups = {CHECK_CPP_FILES})
public void deserializeFromCppDouble() throws IOException {
final int[] nArr = {0, 1, 10, 100, 1000, 10_000, 100_000, 1_000_000};
for (final int n: nArr) {
final byte[] bytes = Files.readAllBytes(cppPath.resolve("tdigest_double_n" + n + "_cpp.sk"));
final TDigestDouble td = TDigestDouble.heapify(MemorySegment.ofArray(bytes));
assertTrue(n == 0 ? td.isEmpty() : !td.isEmpty());
assertEquals(td.getTotalWeight(), n);
if (n > 0) {
assertEquals(td.getMinValue(), 1);
assertEquals(td.getMaxValue(), n);
assertEquals(td.getRank(0), 0);
assertEquals(td.getRank(n + 1), 1);
if (n == 1) {
assertEquals(td.getRank(n), 0.5);
final boolean[] with_buffer = {false, true};
for (final boolean buffered : with_buffer) {
final int[] nArr = {0, 1, 10, 100, 1000, 10_000, 100_000, 1_000_000};
for (final int n : nArr) {
final byte[] bytes;
if (buffered) {
bytes = Files.readAllBytes(cppPath.resolve("tdigest_double_buf_n" + n + "_cpp.sk"));
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@tisonkun tisonkun Dec 19, 2025

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This will fail without this patch.

} else {
assertEquals(td.getRank(n / 2), 0.5, 0.05);
bytes = Files.readAllBytes(cppPath.resolve("tdigest_double_n" + n + "_cpp.sk"));
}
final TDigestDouble td = TDigestDouble.heapify(MemorySegment.ofArray(bytes));
assertTrue(n == 0 ? td.isEmpty() : !td.isEmpty());
assertEquals(td.getTotalWeight(), n);
if (n > 0) {
assertEquals(td.getMinValue(), 1);
assertEquals(td.getMaxValue(), n);
assertEquals(td.getRank(0), 0);
assertEquals(td.getRank(n + 1), 1);
if (n == 1) {
assertEquals(td.getRank(n), 0.5);
} else {
assertEquals(td.getRank(n / 2), 0.5, 0.05);
}
}
}
}
}

@Test(groups = {CHECK_CPP_FILES})
public void deserializeFromCppFloat() throws IOException {
final boolean[] with_buffer = {false, true};
final int[] nArr = {0, 1, 10, 100, 1000, 10_000, 100_000, 1_000_000};
for (final int n: nArr) {
final byte[] bytes = Files.readAllBytes(cppPath.resolve("tdigest_float_n" + n + "_cpp.sk"));
final TDigestDouble td = TDigestDouble.heapify(MemorySegment.ofArray(bytes), true);
assertTrue(n == 0 ? td.isEmpty() : !td.isEmpty());
assertEquals(td.getTotalWeight(), n);
if (n > 0) {
assertEquals(td.getMinValue(), 1);
assertEquals(td.getMaxValue(), n);
assertEquals(td.getRank(0), 0);
assertEquals(td.getRank(n + 1), 1);
if (n == 1) {
assertEquals(td.getRank(n), 0.5);
for (final boolean buffered : with_buffer) {
for (final int n : nArr) {
final byte[] bytes;
if (buffered) {
bytes = Files.readAllBytes(cppPath.resolve("tdigest_float_buf_n" + n + "_cpp.sk"));
} else {
assertEquals(td.getRank(n / 2), 0.5, 0.05);
bytes = Files.readAllBytes(cppPath.resolve("tdigest_float_n" + n + "_cpp.sk"));
}
final TDigestDouble td = TDigestDouble.heapify(MemorySegment.ofArray(bytes), true);
assertTrue(n == 0 ? td.isEmpty() : !td.isEmpty());
assertEquals(td.getTotalWeight(), n);
if (n > 0) {
assertEquals(td.getMinValue(), 1);
assertEquals(td.getMaxValue(), n);
assertEquals(td.getRank(0), 0);
assertEquals(td.getRank(n + 1), 1);
if (n == 1) {
assertEquals(td.getRank(n), 0.5);
} else {
assertEquals(td.getRank(n / 2), 0.5, 0.05);
}
}
}
}
Expand All @@ -81,7 +95,7 @@ public void deserializeFromCppFloat() throws IOException {
@Test(groups = {GENERATE_JAVA_FILES})
public void generateForCppDouble() throws IOException {
final int[] nArr = {0, 1, 10, 100, 1000, 10_000, 100_000, 1_000_000};
for (final int n: nArr) {
for (final int n : nArr) {
final TDigestDouble td = new TDigestDouble((short) 100);
for (int i = 1; i <= n; i++) {
td.update(i);
Expand Down
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