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Percentile functions #44

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Apr 13, 2018
Merged

Percentile functions #44

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166 changes: 166 additions & 0 deletions testware/integration-tests/src/test/java/org/opencypher/gremlin/queries/PercentileTest.java
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@@ -0,0 +1,166 @@
/*
* Copyright (c) 2018 "Neo4j, Inc." [https://neo4j.com]
*
* 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 org.opencypher.gremlin.queries;

import static java.util.Collections.emptyMap;
import static java.util.stream.Collectors.toList;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.catchThrowable;
import static org.assertj.core.api.Assertions.tuple;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;
import org.junit.Before;
import org.junit.ClassRule;
import org.junit.Test;
import org.opencypher.gremlin.rules.GremlinServerExternalResource;

public class PercentileTest {

@ClassRule
public static final GremlinServerExternalResource gremlinServer = new GremlinServerExternalResource();

@Before
public void setUp() {
gremlinServer.gremlinClient().submit("g.V().drop()").all().join();
}

private List<Map<String, Object>> submitAndGet(String cypher) {
return submitAndGet(cypher, emptyMap());
}

private List<Map<String, Object>> submitAndGet(String cypher, Map<String, ?> parameters) {
return gremlinServer.cypherGremlinClient().submit(cypher, parameters).all();
}

@Test
public void percentileCont() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [10, 20, 30] AS i " +
"RETURN " +
"percentileCont(i, 0.0) AS p0, " +
"percentileCont(i, 0.33) AS p33, " +
"percentileCont(i, 0.5) AS p50, " +
"percentileCont(i, 0.66) AS p66, " +
"percentileCont(i, 1.0) AS p100"
);

assertThat(results)
.extracting("p0", "p33", "p50", "p66", "p100")
.containsExactly(tuple(10L, 16.6, 20L, 23.2, 30L));
}

@Test
public void percentileContSingle() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [10] AS i " +
"RETURN percentileCont(i, 0.5) AS p50"
);

assertThat(results)
.extracting("p50")
.containsExactly(10L);
}

@Test
public void percentileContEmpty() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [] AS i " +
"RETURN percentileCont(i, 0.5) AS p50"
);

assertThat(results)
.extracting("p50")
.containsExactly((Object) null);
}

@Test
public void percentileContInvalidArgument() throws Exception {
submitAndGet("CREATE ({prop: 10.0})");
List<Throwable> throwables = Stream.of(1000, -1, 1.1)
.map(param -> catchThrowable(() -> submitAndGet(
"MATCH (n) RETURN percentileCont(n.prop, $param)",
Collections.singletonMap("param", param)
)))
.collect(toList());

assertThat(throwables)
.allSatisfy(throwable ->
assertThat(throwable)
.hasMessageContaining("Number out of range"));
}

@Test
public void percentileDisc() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [10, 20, 30] AS i " +
"RETURN " +
"percentileDisc(i, 0.0) AS p0, " +
"percentileDisc(i, 0.33) AS p33, " +
"percentileDisc(i, 0.34) AS p34, " +
"percentileDisc(i, 0.5) AS p50, " +
"percentileDisc(i, 0.66) AS p66, " +
"percentileDisc(i, 0.67) AS p67, " +
"percentileDisc(i, 1.0) AS p100"
);

assertThat(results)
.extracting("p0", "p33", "p34", "p50", "p66", "p67", "p100")
.containsExactly(tuple(10L, 10L, 20L, 20L, 20L, 30L, 30L));
}

@Test
public void percentileDiscSingle() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [10] AS i " +
"RETURN percentileDisc(i, 0.5) AS p50"
);

assertThat(results)
.extracting("p50")
.containsExactly(10L);
}

@Test
public void percentileDiscEmpty() throws Exception {
List<Map<String, Object>> results = submitAndGet(
"UNWIND [] AS i " +
"RETURN percentileDisc(i, 0.5) AS p50"
);

assertThat(results)
.extracting("p50")
.containsExactly((Object) null);
}

@Test
public void percentileDiscInvalidArgument() throws Exception {
submitAndGet("CREATE ({prop: 10.0})");
List<Throwable> throwables = Stream.of(1000, -1, 1.1)
.map(param -> catchThrowable(() -> submitAndGet(
"MATCH (n) RETURN percentileDisc(n.prop, $param)",
Collections.singletonMap("param", param)
)))
.collect(toList());

assertThat(throwables)
.allSatisfy(throwable ->
assertThat(throwable)
.hasMessageContaining("Number out of range"));
}
}
8 changes: 5 additions & 3 deletions testware/tck/src/test/scala/org/opencypher/gremlin/tck/GremlinErrors.scala
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Expand Up @@ -17,8 +17,8 @@ package org.opencypher.gremlin.tck

import org.opencypher.tools.tck.api.ExecutionFailed
import org.opencypher.tools.tck.constants.TCKErrorDetails._
import org.opencypher.tools.tck.constants.TCKErrorPhases.{COMPILE_TIME, RUNTIME}
import org.opencypher.tools.tck.constants.TCKErrorTypes.{SYNTAX_ERROR, TYPE_ERROR}
import org.opencypher.tools.tck.constants.TCKErrorPhases._
import org.opencypher.tools.tck.constants.TCKErrorTypes._

object GremlinErrors {
val mappings = Map(
Expand Down Expand Up @@ -97,6 +97,8 @@ object GremlinErrors {
"Unsupported graph element type: (.+)" ->
ExecutionFailed(SYNTAX_ERROR, RUNTIME, PROPERTY_ACCESS_ON_NON_MAP),
"Cannot convert .+ to .+" ->
ExecutionFailed(TYPE_ERROR, RUNTIME, INVALID_ARGUMENT_VALUE)
ExecutionFailed(TYPE_ERROR, RUNTIME, INVALID_ARGUMENT_VALUE),
"Number out of range: (.+)" ->
ExecutionFailed(ARGUMENT_ERROR, RUNTIME, NUMBER_OUT_OF_RANGE)
)
}
82 changes: 78 additions & 4 deletions translation/src/main/java/org/opencypher/gremlin/traversal/CustomFunction.java
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Expand Up @@ -22,10 +22,11 @@
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.apache.tinkerpop.gremlin.process.traversal.Path;
import org.apache.tinkerpop.gremlin.process.traversal.Traverser;
Expand Down Expand Up @@ -199,7 +200,7 @@ public static CustomFunction listComprehension(final Object functionTraversal) {
GraphTraversal.Admin admin = GraphTraversal.class.cast(functionTraversal).asAdmin();
return TraversalUtil.apply(item, admin);
})
.collect(Collectors.toList());
.collect(toList());
},
functionTraversal);
}
Expand All @@ -225,7 +226,7 @@ public static CustomFunction pathComprehension() {
.map(CustomFunction::finalizeElements)
.collect(toList());
})
.collect(Collectors.toList()));
.collect(toList()));
}

public static CustomFunction containerIndex(Object index) {
Expand All @@ -247,6 +248,79 @@ public static CustomFunction containerIndex(Object index) {
index);
}

public static CustomFunction percentileCont(double percentile) {
return new CustomFunction(
"percentileCont",
percentileFunction(
percentile,
data -> {
int last = data.size() - 1;
double lowPercentile = Math.floor(percentile * last) / last;
double highPercentile = Math.ceil(percentile * last) / last;
if (lowPercentile == highPercentile) {
return percentileNearest(data, percentile);
}

double scale = (percentile - lowPercentile) / (highPercentile - lowPercentile);
double low = percentileNearest(data, lowPercentile).doubleValue();
double high = percentileNearest(data, highPercentile).doubleValue();
return (high - low) * scale + low;
}
),
percentile
);
}

public static CustomFunction percentileDisc(double percentile) {
return new CustomFunction(
"percentileDisc",
percentileFunction(
percentile,
data -> percentileNearest(data, percentile)
),
percentile
);
}

private static Function<Traverser, Object> percentileFunction(double percentile,
Function<List<Number>, Number> percentileStrategy) {
return traverser -> {
if (percentile < 0 || percentile > 1) {
throw new IllegalArgumentException("Number out of range: " + percentile);
}

Collection<?> coll = (Collection<?>) traverser.get();
boolean invalid = coll.stream()
.anyMatch(o -> !(o == null || o instanceof Number));
if (invalid) {
throw new IllegalArgumentException("Percentile function can only handle numerical values");
}
List<Number> data = coll.stream()
.filter(Objects::nonNull)
.map(o -> (Number) o)
.sorted()
.collect(toList());

int size = data.size();
if (size == 0) {
return Tokens.NULL;
} else if (size == 1) {
return data.get(0);
}

return percentileStrategy.apply(data);
};
}

private static <T> T percentileNearest(List<T> sorted, double percentile) {
int size = sorted.size();
int index = (int) Math.ceil(percentile * size) - 1;
if (index == -1) {
index = 0;
}
return sorted.get(index);
}

public static CustomFunction size() {
return new CustomFunction(
"size", traverser -> traverser.get() instanceof String ?
Expand Down Expand Up @@ -288,7 +362,7 @@ private static Object nullToToken(Object maybeNull) {
return maybeNull == null ? Tokens.NULL : maybeNull;
}

public static Object pathToList(Object value) {
private static Object pathToList(Object value) {
return value instanceof Path ? new ArrayList<>(((Path) value).objects()) : value;
}

Expand Down
18 changes: 14 additions & 4 deletions translation/src/main/scala/org/opencypher/gremlin/translation/walker/ProjectionWalker.scala
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Expand Up @@ -487,14 +487,24 @@ private class ProjectionWalker[T, P](context: StatementContext[T, P], g: Gremlin
traversal.is(p.neq(NULL))

fnName.toLowerCase match {
case "avg" => (Aggregation, traversal.mean())
case "collect" => (Aggregation, traversal.fold())
case "count" => (Aggregation, traversal.count())
case "avg" =>
(Aggregation, traversal.mean())
case "collect" =>
(Aggregation, traversal.fold())
case "count" =>
(Aggregation, traversal.count())
case "max" =>
(Aggregation, traversal.max().choose(p.isEq(Integer.MIN_VALUE), __.constant(NULL)))
case "min" =>
(Aggregation, traversal.min().choose(p.isEq(Integer.MAX_VALUE), __.constant(NULL)))
case "sum" => (Aggregation, traversal.sum())
case "percentilecont" =>
val percentile = inlineExpressionValue(args(1), context, classOf[java.lang.Number]).doubleValue()
(Aggregation, traversal.fold().map(CustomFunction.percentileCont(percentile)))
case "percentiledisc" =>
val percentile = inlineExpressionValue(args(1), context, classOf[java.lang.Number]).doubleValue()
(Aggregation, traversal.fold().map(CustomFunction.percentileDisc(percentile)))
case "sum" =>
(Aggregation, traversal.sum())
case _ =>
throw new SyntaxException(s"Unknown function '$fnName'")
}
Expand Down