| /* |
| * 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.apache.commons.numbers.gamma; |
| |
| import org.junit.jupiter.api.Assertions; |
| import org.junit.jupiter.api.Test; |
| |
| /** |
| * Tests for {@link Gamma}. |
| */ |
| public class GammaTest { |
| /** |
| * Reference data for the {@link Gamma#value(double)} function. This |
| * data was generated with the following <a |
| * href="http://maxima.sourceforge.net/">Maxima</a> script. |
| * |
| * <pre> |
| * kill(all); |
| * |
| * fpprec : 64; |
| * |
| * EPSILON : 10**(-fpprec + 1); |
| * isInteger(x) := abs(x - floor(x)) <= EPSILON * abs(x); |
| * |
| * x : makelist(bfloat(i / 8), i, -160, 160); |
| * x : append(x, makelist(bfloat(i / 2), i, 41, 200)); |
| * |
| * for i : 1 while i <= length(x) do if not(isInteger(x[i])) then |
| * print("{", float(x[i]), ",", float(gamma(x[i])), "},"); |
| * </pre> |
| */ |
| private static final double[][] GAMMA_REF = { |
| {-19.875, 4.920331854832504e-18}, |
| {-19.75, 3.879938752480031e-18}, |
| {-19.625, 4.323498423815027e-18}, |
| {-19.5, 5.811045977502237e-18}, |
| {-19.375, 9.14330910942125e-18}, |
| {-19.25, 1.735229114436739e-17}, |
| {-19.125, 4.653521565668223e-17}, |
| {-18.875, -9.779159561479603e-17}, |
| {-18.75, -7.662879036148061e-17}, |
| {-18.625, -8.484865656736991e-17}, |
| {-18.5, -1.133153965612936e-16}, |
| {-18.375, -1.771516139950367e-16}, |
| {-18.25, -3.340316045290721e-16}, |
| {-18.125, -8.899859994340475e-16}, |
| {-17.875, 1.845816367229275e-15}, |
| {-17.75, 1.436789819277761e-15}, |
| {-17.625, 1.580306228567265e-15}, |
| {-17.5, 2.096334836383932e-15}, |
| {-17.375, 3.255160907158799e-15}, |
| {-17.25, 6.096076782655566e-15}, |
| {-17.125, 1.613099623974211e-14}, |
| {-16.875, -3.29939675642233e-14}, |
| {-16.75, -2.550301929218027e-14}, |
| {-16.625, -2.785289727849803e-14}, |
| {-16.5, -3.66858596367188e-14}, |
| {-16.375, -5.655842076188414e-14}, |
| {-16.25, -1.051573245008085e-13}, |
| {-16.125, -2.762433106055837e-13}, |
| {-15.875, 5.567732026462681e-13}, |
| {-15.75, 4.271755731440195e-13}, |
| {-15.625, 4.630544172550298e-13}, |
| {-15.5, 6.053166840058604e-13}, |
| {-15.375, 9.261441399758529e-13}, |
| {-15.25, 1.708806523138138e-12}, |
| {-15.125, 4.454423383515037e-12}, |
| {-14.875, -8.838774592009505e-12}, |
| {-14.75, -6.728015277018307e-12}, |
| {-14.625, -7.235225269609841e-12}, |
| {-14.5, -9.382408602090835e-12}, |
| {-14.375, -1.423946615212874e-11}, |
| {-14.25, -2.605929947785661e-11}, |
| {-14.125, -6.737315367566492e-11}, |
| {-13.875, 1.314767720561414e-10}, |
| {-13.75, 9.923822533602004e-11}, |
| {-13.625, 1.058151695680439e-10}, |
| {-13.5, 1.360449247303171e-10}, |
| {-13.375, 2.046923259368506e-10}, |
| {-13.25, 3.713450175594567e-10}, |
| {-13.125, 9.516457956687671e-10}, |
| {-12.875, -1.8242402122789617e-9}, |
| {-12.75, -1.3645255983702756e-9}, |
| {-12.625, -1.4417316853645984e-9}, |
| {-12.5, -1.836606483859281e-9}, |
| {-12.375, -2.7377598594053765e-9}, |
| {-12.25, -4.9203214826628017e-9}, |
| {-12.125, -1.2490351068152569e-8}, |
| {-11.875, 2.3487092733091633e-8}, |
| {-11.75, 1.7397701379221012e-8}, |
| {-11.625, 1.8201862527728055e-8}, |
| {-11.5, 2.295758104824101e-8}, |
| {-11.375, 3.3879778260141535e-8}, |
| {-11.25, 6.027393816261931e-8}, |
| {-11.125, 1.5144550670134987e-7}, |
| {-10.875, -2.7890922620546316e-7}, |
| {-10.75, -2.044229912058469e-7}, |
| {-10.625, -2.1159665188483867e-7}, |
| {-10.5, -2.640121820547716e-7}, |
| {-10.375, -3.8538247770911e-7}, |
| {-10.25, -6.780818043294673e-7}, |
| {-10.125, -1.6848312620525174e-6}, |
| {-9.875, 3.0331378349844124e-6}, |
| {-9.75, 2.1975471554628537e-6}, |
| {-9.625, 2.2482144262764103e-6}, |
| {-9.5, 2.772127911575102e-6}, |
| {-9.375, 3.998343206232017e-6}, |
| {-9.25, 6.95033849437704e-6}, |
| {-9.125, 1.7058916528281737e-5}, |
| {-8.875, -2.9952236120471065e-5}, |
| {-8.75, -2.1426084765762826e-5}, |
| {-8.625, -2.163906385291045e-5}, |
| {-8.5, -2.633521515996347e-5}, |
| {-8.375, -3.748446755842515e-5}, |
| {-8.25, -6.429063107298763e-5}, |
| {-8.125, -1.5566261332057085e-4}, |
| {-7.875, 2.658260955691807e-4}, |
| {-7.75, 1.874782417004247e-4}, |
| {-7.625, 1.8663692573135265e-4}, |
| {-7.5, 2.238493288596895e-4}, |
| {-7.375, 3.1393241580181064e-4}, |
| {-7.25, 5.303977063521479e-4}, |
| {-7.125, .001264758733229638}, |
| {-6.875, -.002093380502607298}, |
| {-6.75, -.001452956373178292}, |
| {-6.625, -.001423106558701564}, |
| {-6.5, -.001678869966447671}, |
| {-6.375, -.002315251566538353}, |
| {-6.25, -.003845383371053072}, |
| {-6.125, -.009011405974261174}, |
| {-5.875, .01439199095542518}, |
| {-5.75, .009807455518953468}, |
| {-5.625, .009428080951397862}, |
| {-5.5, .01091265478190986}, |
| {-5.375, 0.014759728736682}, |
| {-5.25, 0.0240336460690817}, |
| {-5.125, .05519486159234969}, |
| {-4.875, -0.0845529468631229}, |
| {-4.75, -.05639286923398244}, |
| {-4.625, -.05303295535161297}, |
| {-4.5, -.06001960130050425}, |
| {-4.375, -.07933354195966577}, |
| {-4.25, -.1261766418626789}, |
| {-4.125, -.2828736656607921}, |
| {-3.875, .4121956159577241}, |
| {-3.75, .2678661288614166}, |
| {-3.625, 0.24527741850121}, |
| {-3.5, .2700882058522691}, |
| {-3.375, .3470842460735378}, |
| {-3.25, .5362507279163854}, |
| {-3.125, 1.166853870850768}, |
| {-2.875, -1.597258011836181}, |
| {-2.75, -1.004497983230312}, |
| {-2.625, -.8891306420668862}, |
| {-2.5, -.9453087204829419}, |
| {-2.375, -1.17140933049819}, |
| {-2.25, -1.742814865728253}, |
| {-2.125, -3.646418346408649}, |
| {-1.875, 4.59211678402902}, |
| {-1.75, 2.762369453883359}, |
| {-1.625, 2.333967935425576}, |
| {-1.5, 2.363271801207355}, |
| {-1.375, 2.782097159933201}, |
| {-1.25, 3.921333447888569}, |
| {-1.125, 7.748638986118379}, |
| {-0.875, -8.610218970054413}, |
| {-0.75, -4.834146544295877}, |
| {-0.625, -3.792697895066561}, |
| {-0.5, -3.544907701811032}, |
| {-0.375, -3.825383594908152}, |
| {-0.25, -4.901666809860711}, |
| {-0.125, -8.717218859383175}, |
| {0.125, 7.533941598797612}, |
| {0.25, 3.625609908221908}, |
| {0.375, 2.370436184416601}, |
| {0.5, 1.772453850905516}, |
| {0.625, 1.434518848090557}, |
| {0.75, 1.225416702465178}, |
| {0.875, 1.089652357422897}, |
| {1.0, 1.0}, |
| {1.125, .9417426998497015}, |
| {1.25, 0.906402477055477}, |
| {1.375, .8889135691562253}, |
| {1.5, 0.886226925452758}, |
| {1.625, 0.896574280056598}, |
| {1.75, .9190625268488832}, |
| {1.875, .9534458127450348}, |
| {2.0, 1.0}, |
| {2.125, 1.059460537330914}, |
| {2.25, 1.133003096319346}, |
| {2.375, 1.22225615758981}, |
| {2.5, 1.329340388179137}, |
| {2.625, 1.456933205091972}, |
| {2.75, 1.608359421985546}, |
| {2.875, 1.78771089889694}, |
| {3.0, 2.0}, |
| {3.125, 2.251353641828193}, |
| {3.25, 2.549256966718529}, |
| {3.375, 2.902858374275799}, |
| {3.5, 3.323350970447843}, |
| {3.625, 3.824449663366426}, |
| {3.75, 4.422988410460251}, |
| {3.875, 5.139668834328703}, |
| {4.0, 6.0}, |
| {4.125, 7.035480130713102}, |
| {4.25, 8.28508514183522}, |
| {4.375, 9.797147013180819}, |
| {4.5, 11.63172839656745}, |
| {4.625, 13.86363002970329}, |
| {4.75, 16.58620653922594}, |
| {4.875, 19.91621673302373}, |
| {5.0, 24.0}, |
| {5.125, 29.02135553919155}, |
| {5.25, 35.21161185279968}, |
| {5.375, 42.86251818266609}, |
| {5.5, 52.34277778455352}, |
| {5.625, 64.11928888737773}, |
| {5.75, 78.78448106132322}, |
| {5.875, 97.09155657349066}, |
| {6.0, 120.0}, |
| {6.125, 148.7344471383567}, |
| {6.25, 184.8609622271983}, |
| {6.375, 230.3860352318302}, |
| {6.5, 287.8852778150443}, |
| {6.625, 360.6709999914997}, |
| {6.75, 453.0107661026085}, |
| {6.875, 570.4128948692577}, |
| {7.0, 720.0}, |
| {7.125, 910.9984887224346}, |
| {7.25, 1155.38101391999}, |
| {7.375, 1468.710974602918}, |
| {7.5, 1871.254305797788}, |
| {7.625, 2389.445374943686}, |
| {7.75, 3057.822671192607}, |
| {7.875, 3921.588652226146}, |
| {8.0, 5040.0}, |
| {8.125, 6490.864232147346}, |
| {8.25, 8376.512350919926}, |
| {8.375, 10831.74343769652}, |
| {8.5, 14034.40729348341}, |
| {8.625, 18219.5209839456}, |
| {8.75, 23698.12570174271}, |
| {8.875, 30882.5106362809}, |
| {9.0, 40320.0}, |
| {9.125, 52738.27188619719}, |
| {9.25, 69106.22689508938}, |
| {9.375, 90715.85129070834}, |
| {9.5, 119292.461994609}, |
| {9.625, 157143.3684865308}, |
| {9.75, 207358.5998902487}, |
| {9.875, 274082.281896993}, |
| {10.0, 362880.0}, |
| {10.125, 481236.7309615494}, |
| {10.25, 639232.5987795768}, |
| {10.375, 850461.1058503906}, |
| {10.5, 1133278.388948786}, |
| {10.625, 1512504.921682859}, |
| {10.75, 2021746.348929925}, |
| {10.875, 2706562.533732806}, |
| {11.0, 3628800.0}, |
| {11.125, 4872521.900985687}, |
| {11.25, 6552134.137490662}, |
| {11.375, 8823533.973197803}, |
| {11.5, 1.1899423083962249e+7}, |
| {11.625, 1.6070364792880382e+7}, |
| {11.75, 2.1733773250996688e+7}, |
| {11.875, 2.943386755434427e+7}, |
| {12.0, 3.99168e+7}, |
| {12.125, 5.420680614846578e+7}, |
| {12.25, 7.371150904676994e+7}, |
| {12.375, 1.0036769894512501e+8}, |
| {12.5, 1.3684336546556586e+8}, |
| {12.625, 1.8681799071723443e+8}, |
| {12.75, 2.5537183569921107e+8}, |
| {12.875, 3.4952717720783816e+8}, |
| {13.0, 4.790016e+8}, |
| {13.125, 6.572575245501475e+8}, |
| {13.25, 9.029659858229319e+8}, |
| {13.375, 1.2420502744459219e+9}, |
| {13.5, 1.7105420683195732e+9}, |
| {13.625, 2.3585771328050845e+9}, |
| {13.75, 3.2559909051649416e+9}, |
| {13.875, 4.500162406550916e+9}, |
| {14.0, 6.2270208e+9}, |
| {14.125, 8.626505009720685e+9}, |
| {14.25, 1.196429931215385e+10}, |
| {14.375, 1.66124224207142e+10}, |
| {14.5, 2.309231792231424e+10}, |
| {14.625, 3.213561343446927e+10}, |
| {14.75, 4.476987494601794e+10}, |
| {14.875, 6.243975339089396e+10}, |
| {15.0, 8.71782912e+10}, |
| {15.125, 1.218493832623047e+11}, |
| {15.25, 1.704912651981923e+11}, |
| {15.375, 2.388035722977667e+11}, |
| {15.5, 3.348386098735565e+11}, |
| {15.625, 4.699833464791132e+11}, |
| {15.75, 6.603556554537646e+11}, |
| {15.875, 9.287913316895475e+11}, |
| {16.0, 1.307674368e+12}, |
| {16.125, 1.842971921842358e+12}, |
| {16.25, 2.599991794272433e+12}, |
| {16.375, 3.671604924078163e+12}, |
| {16.5, 5.189998453040126e+12}, |
| {16.625, 7.343489788736144e+12}, |
| {16.75, 1.040060157339679e+13}, |
| {16.875, 1.474456239057157e+13}, |
| {17.0, 2.0922789888e+13}, |
| {17.125, 2.971792223970803e+13}, |
| {17.25, 4.224986665692704e+13}, |
| {17.375, 6.012253063177992e+13}, |
| {17.5, 8.563497447516206e+13}, |
| {17.625, 1.220855177377384e+14}, |
| {17.75, 1.742100763543963e+14}, |
| {17.875, 2.488144903408952e+14}, |
| {18.0, 3.55687428096e+14}, |
| {18.125, 5.08919418355e+14}, |
| {18.25, 7.288101998319914e+14}, |
| {18.375, 1.044628969727176e+15}, |
| {18.5, 1.498612053315336e+15}, |
| {18.625, 2.151757250127639e+15}, |
| {18.75, 3.092228855290534e+15}, |
| {18.875, 4.447559014843502e+15}, |
| {19.0, 6.402373705728e+15}, |
| {19.125, 9.224164457684374e+15}, |
| {19.25, 1.330078614693384e+16}, |
| {19.375, 1.919505731873686e+16}, |
| {19.5, 2.772432298633372e+16}, |
| {19.625, 4.007647878362728e+16}, |
| {19.75, 5.797929103669752e+16}, |
| {19.875, 8.39476764051711e+16}, |
| {20.0, 1.21645100408832e+17}, |
| {20.5, 5.406242982335075e+17}, |
| {21.0, 2.43290200817664e+18}, |
| {21.5, 1.10827981137869e+19}, |
| {22.0, 5.109094217170944e+19}, |
| {22.5, 2.382801594464184e+20}, |
| {23.0, 1.124000727777608e+21}, |
| {23.5, 5.361303587544415e+21}, |
| {24.0, 2.585201673888498e+22}, |
| {24.5, 1.259906343072938e+23}, |
| {25.0, 6.204484017332395e+23}, |
| {25.5, 3.086770540528697e+24}, |
| {26.0, 1.551121004333099e+25}, |
| {26.5, 7.871264878348176e+25}, |
| {27.0, 4.032914611266056e+26}, |
| {27.5, 2.085885192762267e+27}, |
| {28.0, 1.088886945041835e+28}, |
| {28.5, 5.736184280096234e+28}, |
| {29.0, 3.048883446117139e+29}, |
| {29.5, 1.634812519827427e+30}, |
| {30.0, 8.841761993739702e+30}, |
| {30.5, 4.822696933490909e+31}, |
| {31.0, 2.65252859812191e+32}, |
| {31.5, 1.470922564714727e+33}, |
| {32.0, 8.222838654177922e+33}, |
| {32.5, 4.633406078851391e+34}, |
| {33.0, 2.631308369336935e+35}, |
| {33.5, 1.505856975626702e+36}, |
| {34.0, 8.683317618811885e+36}, |
| {34.5, 5.044620868349451e+37}, |
| {35.0, 2.952327990396041e+38}, |
| {35.5, 1.740394199580561e+39}, |
| {36.0, 1.033314796638614e+40}, |
| {36.5, 6.178399408510991e+40}, |
| {37.0, 3.719933267899013e+41}, |
| {37.5, 2.255115784106512e+42}, |
| {38.0, 1.376375309122634e+43}, |
| {38.5, 8.456684190399419e+43}, |
| {39.0, 5.230226174666011e+44}, |
| {39.5, 3.255823413303776e+45}, |
| {40.0, 2.039788208119745e+46}, |
| {40.5, 1.286050248254992e+47}, |
| {41.0, 8.159152832478976e+47}, |
| {41.5, 5.208503505432716e+48}, |
| {42.0, 3.345252661316381e+49}, |
| {42.5, 2.161528954754577e+50}, |
| {43.0, 1.40500611775288e+51}, |
| {43.5, 9.186498057706953e+51}, |
| {44.0, 6.041526306337383e+52}, |
| {44.5, 3.996126655102524e+53}, |
| {45.0, 2.658271574788449e+54}, |
| {45.5, 1.778276361520623e+55}, |
| {46.0, 1.196222208654802e+56}, |
| {46.5, 8.091157444918836e+56}, |
| {47.0, 5.502622159812088e+57}, |
| {47.5, 3.762388211887259e+58}, |
| {48.0, 2.586232415111682e+59}, |
| {48.5, 1.787134400646448e+60}, |
| {49.0, 1.241391559253607e+61}, |
| {49.5, 8.667601843135273e+61}, |
| {50.0, 6.082818640342675e+62}, |
| {50.5, 4.290462912351959e+63}, |
| {51.0, 3.041409320171338e+64}, |
| {51.5, 2.16668377073774e+65}, |
| {52.0, 1.551118753287382e+66}, |
| {52.5, 1.115842141929936e+67}, |
| {53.0, 8.065817517094388e+67}, |
| {53.5, 5.858171245132164e+68}, |
| {54.0, 4.274883284060025e+69}, |
| {54.5, 3.134121616145708e+70}, |
| {55.0, 2.308436973392413e+71}, |
| {55.5, 1.70809628079941e+72}, |
| {56.0, 1.269640335365828e+73}, |
| {56.5, 9.479934358436728e+73}, |
| {57.0, 7.109985878048635e+74}, |
| {57.5, 5.356162912516752e+75}, |
| {58.0, 4.052691950487721e+76}, |
| {58.5, 3.079793674697132e+77}, |
| {59.0, 2.350561331282878e+78}, |
| {59.5, 1.801679299697822e+79}, |
| {60.0, 1.386831185456898e+80}, |
| {60.5, 1.071999183320204e+81}, |
| {61.0, 8.320987112741391e+81}, |
| {61.5, 6.485595059087236e+82}, |
| {62.0, 5.075802138772249e+83}, |
| {62.5, 3.98864096133865e+84}, |
| {63.0, 3.146997326038794e+85}, |
| {63.5, 2.492900600836656e+86}, |
| {64.0, 1.98260831540444e+87}, |
| {64.5, 1.582991881531277e+88}, |
| {65.0, 1.268869321858841e+89}, |
| {65.5, 1.021029763587673e+90}, |
| {66.0, 8.247650592082472e+90}, |
| {66.5, 6.687744951499262e+91}, |
| {67.0, 5.443449390774431e+92}, |
| {67.5, 4.447350392747009e+93}, |
| {68.0, 3.647111091818868e+94}, |
| {68.5, 3.001961515104231e+95}, |
| {69.0, 2.48003554243683e+96}, |
| {69.5, 2.056343637846398e+97}, |
| {70.0, 1.711224524281413e+98}, |
| {70.5, 1.429158828303247e+99}, |
| {71.0, 1.19785716699699e+100}, |
| {71.5, 1.00755697395379e+101}, |
| {72.0, 8.50478588567862e+101}, |
| {72.5, 7.20403236376959e+102}, |
| {73.0, 6.12344583768861e+103}, |
| {73.5, 5.22292346373295e+104}, |
| {74.0, 4.47011546151268e+105}, |
| {74.5, 3.83884874584372e+106}, |
| {75.0, 3.30788544151939e+107}, |
| {75.5, 2.85994231565357e+108}, |
| {76.0, 2.48091408113954e+109}, |
| {76.5, 2.15925644831845e+110}, |
| {77.0, 1.88549470166605e+111}, |
| {77.5, 1.65183118296361e+112}, |
| {78.0, 1.45183092028286e+113}, |
| {78.5, 1.2801691667968e+114}, |
| {79.0, 1.13242811782063e+115}, |
| {79.5, 1.00493279593549e+116}, |
| {80.0, 8.94618213078298e+116}, |
| {80.5, 7.98921572768712e+117}, |
| {81.0, 7.15694570462638e+118}, |
| {81.5, 6.43131866078814e+119}, |
| {82.0, 5.79712602074737e+120}, |
| {82.5, 5.24152470854233e+121}, |
| {83.0, 4.75364333701284e+122}, |
| {83.5, 4.32425788454742e+123}, |
| {84.0, 3.94552396972066e+124}, |
| {84.5, 3.6107553335971e+125}, |
| {85.0, 3.31424013456535e+126}, |
| {85.5, 3.05108825688955e+127}, |
| {86.0, 2.81710411438055e+128}, |
| {86.5, 2.60868045964056e+129}, |
| {87.0, 2.42270953836727e+130}, |
| {87.5, 2.25650859758909e+131}, |
| {88.0, 2.10775729837953e+132}, |
| {88.5, 1.97444502289045e+133}, |
| {89.0, 1.85482642257398e+134}, |
| {89.5, 1.74738384525805e+135}, |
| {90.0, 1.65079551609085e+136}, |
| {90.5, 1.56390854150595e+137}, |
| {91.0, 1.48571596448176e+138}, |
| {91.5, 1.41533723006289e+139}, |
| {92.0, 1.3520015276784e+140}, |
| {92.5, 1.29503356550754e+141}, |
| {93.0, 1.24384140546413e+142}, |
| {93.5, 1.19790604809448e+143}, |
| {94.0, 1.15677250708164e+144}, |
| {94.5, 1.12004215496834e+145}, |
| {95.0, 1.08736615665674e+146}, |
| {95.5, 1.05843983644508e+147}, |
| {96.0, 1.03299784882391e+148}, |
| {96.5, 1.01081004380505e+149}, |
| {97.0, 9.9167793487095e+149}, |
| {97.5, 9.75431692271873e+150}, |
| {98.0, 9.61927596824821e+151}, |
| {98.5, 9.51045899965076e+152}, |
| {99.0, 9.42689044888325e+153}, |
| {99.5, 9.367802114656e+154}, |
| {100.0, 9.33262154439441e+155}, |
| }; |
| |
| @Test |
| void testGamma() { |
| for (int i = 0; i < GAMMA_REF.length; i++) { |
| final double[] ref = GAMMA_REF[i]; |
| final double x = ref[0]; |
| final double expected = ref[1]; |
| final double actual = Gamma.value(x); |
| final double absX = Math.abs(x); |
| final int ulps; |
| if (absX <= 8.0) { |
| ulps = 3; |
| } else if (absX <= 20.0) { |
| ulps = 5; |
| } else if (absX <= 30.0) { |
| ulps = 50; |
| } else if (absX <= 50.0) { |
| ulps = 180; |
| } else { |
| ulps = 500; |
| } |
| final double tol = ulps * Math.ulp(expected); |
| Assertions.assertEquals(expected, actual, tol, Double.toString(x)); |
| } |
| } |
| |
| @Test |
| void testGammaNegativeInteger() { |
| for (int i = -100; i <= 0; i++) { |
| Assertions.assertTrue(Double.isNaN(Gamma.value(i)), Integer.toString(i)); |
| } |
| } |
| |
| @Test |
| void testGammaNegativeDouble() { |
| // check that the gamma function properly switches sign |
| // see: https://en.wikipedia.org/wiki/Gamma_function |
| |
| double previousGamma = Gamma.value(-18.5); |
| for (double x = -19.5; x > -25; x -= 1.0) { |
| double gamma = Gamma.value(x); |
| Assertions.assertEquals((int) Math.signum(previousGamma), -(int) Math.signum(gamma)); |
| |
| previousGamma = gamma; |
| } |
| } |
| } |
