/*
 * 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.lucene.document;

import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.ByteBuffersDirectory;
import org.apache.lucene.store.Directory;
import org.apache.lucene.tests.util.LuceneTestCase;

public class TestFeatureFieldSigmoidOverflow extends LuceneTestCase {

  public void testScoreAtPivotWithSteepExponent() throws Exception {
    try (Directory dir = new ByteBuffersDirectory()) {
      try (IndexWriter w = new IndexWriter(dir, new IndexWriterConfig())) {
        Document doc = new Document();
        doc.add(new FeatureField("f", "x", 1 << 20));
        w.addDocument(doc);
      }
      try (DirectoryReader r = DirectoryReader.open(dir)) {
        TopDocs td =
            new IndexSearcher(r).search(FeatureField.newSigmoidQuery("f", "x", 1, 1 << 20, 60), 1);
        // expected weight/2 = 0.5 at S = pivot; actual NaN, because pivot^60 = 2^1200 overflows
        assertEquals(0.5f, td.scoreDocs[0].score, 1e-6f);
      }
    }
  }
}