diff --git a/libs/core/src/main/java/org/elasticsearch/common/util/ESSloppyMath.java b/libs/core/src/main/java/org/elasticsearch/common/util/ESSloppyMath.java new file mode 100644 index 0000000000000..9c36b3f3e17a5 --- /dev/null +++ b/libs/core/src/main/java/org/elasticsearch/common/util/ESSloppyMath.java @@ -0,0 +1,180 @@ +/* + * 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. + */ +package org.elasticsearch.common.util; + +/* + * ============================================================================= + * + * sinh and atan ported from + * https://github.com/yannrichet/jmathplot/blob/f25426e0ab0e68647ad2b75f577c7be050ecac86/src/main/java/org/math/plot/utils/FastMath.java + * (Apache 2.0) Copyright 2012 Jeff Hain, which is partially derived from fdlibm package + * + * ============================================================================= + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ============================================================================= + */ + + +/** + * Similar to Lucene's SloppyMath, but for additional math functions. + */ +public class ESSloppyMath { + + private ESSloppyMath() {} + + //-------------------------------------------------------------------------- + // RE-USABLE CONSTANTS + //-------------------------------------------------------------------------- + + private static final double ONE_DIV_F2 = 1/2.0; + private static final double ONE_DIV_F3 = 1/6.0; + private static final double ONE_DIV_F4 = 1/24.0; + private static final double TWO_POW_N28 = Double.longBitsToDouble(0x3E30000000000000L); + private static final double TWO_POW_66 = Double.longBitsToDouble(0x4410000000000000L); + private static final double LOG_DOUBLE_MAX_VALUE = StrictMath.log(Double.MAX_VALUE); + + //-------------------------------------------------------------------------- + // CONSTANTS AND TABLES FOR ATAN + //-------------------------------------------------------------------------- + + // We use the formula atan(-x) = -atan(x) + // ---> we only have to compute atan(x) on [0,+infinity[. + // For values corresponding to angles not close to +-PI/2, we use look-up tables; + // for values corresponding to angles near +-PI/2, we use code derived from fdlibm. + + // Supposed to be >= tan(67.7deg), as fdlibm code is supposed to work with values > 2.4375. + private static final double ATAN_MAX_VALUE_FOR_TABS = StrictMath.tan(Math.toRadians(74.0)); + + private static final int ATAN_TABS_SIZE = 1<<12 + 1; + private static final double ATAN_DELTA = ATAN_MAX_VALUE_FOR_TABS/(ATAN_TABS_SIZE - 1); + private static final double ATAN_INDEXER = 1/ATAN_DELTA; + private static final double[] atanTab = new double[ATAN_TABS_SIZE]; + private static final double[] atanDer1DivF1Tab = new double[ATAN_TABS_SIZE]; + private static final double[] atanDer2DivF2Tab = new double[ATAN_TABS_SIZE]; + private static final double[] atanDer3DivF3Tab = new double[ATAN_TABS_SIZE]; + private static final double[] atanDer4DivF4Tab = new double[ATAN_TABS_SIZE]; + + private static final double ATAN_HI3 = Double.longBitsToDouble(0x3ff921fb54442d18L); // 1.57079632679489655800e+00 atan(inf)hi + private static final double ATAN_LO3 = Double.longBitsToDouble(0x3c91a62633145c07L); // 6.12323399573676603587e-17 atan(inf)lo + private static final double ATAN_AT0 = Double.longBitsToDouble(0x3fd555555555550dL); // 3.33333333333329318027e-01 + private static final double ATAN_AT1 = Double.longBitsToDouble(0xbfc999999998ebc4L); // -1.99999999998764832476e-01 + private static final double ATAN_AT2 = Double.longBitsToDouble(0x3fc24924920083ffL); // 1.42857142725034663711e-01 + private static final double ATAN_AT3 = Double.longBitsToDouble(0xbfbc71c6fe231671L); // -1.11111104054623557880e-01 + private static final double ATAN_AT4 = Double.longBitsToDouble(0x3fb745cdc54c206eL); // 9.09088713343650656196e-02 + private static final double ATAN_AT5 = Double.longBitsToDouble(0xbfb3b0f2af749a6dL); // -7.69187620504482999495e-02 + private static final double ATAN_AT6 = Double.longBitsToDouble(0x3fb10d66a0d03d51L); // 6.66107313738753120669e-02 + private static final double ATAN_AT7 = Double.longBitsToDouble(0xbfadde2d52defd9aL); // -5.83357013379057348645e-02 + private static final double ATAN_AT8 = Double.longBitsToDouble(0x3fa97b4b24760debL); // 4.97687799461593236017e-02 + private static final double ATAN_AT9 = Double.longBitsToDouble(0xbfa2b4442c6a6c2fL); // -3.65315727442169155270e-02 + private static final double ATAN_AT10 = Double.longBitsToDouble(0x3f90ad3ae322da11L); // 1.62858201153657823623e-02 + + static { + // atan + for (int i=0;i ATAN_MAX_VALUE_FOR_TABS, or value is NaN + // This part is derived from fdlibm. + if (value < TWO_POW_66) { + double x = -1/value; + double x2 = x*x; + double x4 = x2*x2; + double s1 = x2*(ATAN_AT0+x4*(ATAN_AT2+x4*(ATAN_AT4+x4*(ATAN_AT6+x4*(ATAN_AT8+x4*ATAN_AT10))))); + double s2 = x4*(ATAN_AT1+x4*(ATAN_AT3+x4*(ATAN_AT5+x4*(ATAN_AT7+x4*ATAN_AT9)))); + double result = ATAN_HI3-((x*(s1+s2)-ATAN_LO3)-x); + return negateResult ? -result : result; + } else { // value >= 2^66, or value is NaN + if (Double.isNaN(value)) { + return Double.NaN; + } else { + return negateResult ? -Math.PI/2 : Math.PI/2; + } + } + } + } +} diff --git a/libs/core/src/test/java/org/elasticsearch/common/util/ESSloppyMathTests.java b/libs/core/src/test/java/org/elasticsearch/common/util/ESSloppyMathTests.java new file mode 100644 index 0000000000000..35afbe77ff882 --- /dev/null +++ b/libs/core/src/test/java/org/elasticsearch/common/util/ESSloppyMathTests.java @@ -0,0 +1,53 @@ +/* + * 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. + */ +package org.elasticsearch.common.util; + +import org.elasticsearch.test.ESTestCase; + +import static org.elasticsearch.common.util.ESSloppyMath.atan; +import static org.elasticsearch.common.util.ESSloppyMath.sinh; + +public class ESSloppyMathTests extends ESTestCase { + + // accuracy for atan(x) + static double ATAN_DELTA = 1E-15; + // accuracy for sinh(x) + static double SINH_DELTA = 1E-15; // for small x + + public void testAtan() { + assertTrue(Double.isNaN(atan(Double.NaN))); + assertEquals(-Math.PI/2, atan(Double.NEGATIVE_INFINITY), ATAN_DELTA); + assertEquals(Math.PI/2, atan(Double.POSITIVE_INFINITY), ATAN_DELTA); + for (int i = 0; i < 10000; i++) { + assertEquals(StrictMath.atan(i), atan(i), ATAN_DELTA); + assertEquals(StrictMath.atan(-i), atan(-i), ATAN_DELTA); + } + } + + public void testSinh() { + assertTrue(Double.isNaN(sinh(Double.NaN))); + assertEquals(Double.NEGATIVE_INFINITY, sinh(Double.NEGATIVE_INFINITY), SINH_DELTA); + assertEquals(Double.POSITIVE_INFINITY, sinh(Double.POSITIVE_INFINITY), SINH_DELTA); + for (int i = 0; i < 10000; i++) { + double d = randomDoubleBetween(-2 * Math.PI, 2 * Math.PI, true); + if (random().nextBoolean()) { + d = -d; + } + assertEquals(StrictMath.sinh(d), sinh(d), SINH_DELTA); + } + } +} diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoTileUtils.java b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoTileUtils.java index c417be016288d..19381e87fedb6 100644 --- a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoTileUtils.java +++ b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoTileUtils.java @@ -20,6 +20,7 @@ import org.elasticsearch.ElasticsearchParseException; import org.elasticsearch.common.geo.GeoPoint; +import org.elasticsearch.common.util.ESSloppyMath; import org.elasticsearch.common.xcontent.ObjectParser.ValueType; import org.elasticsearch.common.xcontent.XContentParser; import org.elasticsearch.common.xcontent.support.XContentMapValues; @@ -210,7 +211,7 @@ private static int validateZXY(int zoom, int xTile, int yTile) { private static GeoPoint zxyToGeoPoint(int zoom, int xTile, int yTile) { final int tiles = validateZXY(zoom, xTile, yTile); final double n = Math.PI - (2.0 * Math.PI * (yTile + 0.5)) / tiles; - final double lat = Math.toDegrees(Math.atan(Math.sinh(n))); + final double lat = Math.toDegrees(ESSloppyMath.atan(ESSloppyMath.sinh(n))); final double lon = ((xTile + 0.5) / tiles * 360.0) - 180; return new GeoPoint(lat, lon); }