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1   /*
2    * Licensed to the Hipparchus project under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The Hipparchus project licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      https://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.hipparchus.samples.complex;
19  
20  import org.hipparchus.complex.Complex;
21  import org.hipparchus.util.FastMath;
22  
23  /** Domain coloring enhancing modules changes.
24   * <p>
25   * Value represents module but uses a sawtooth function.
26   * </p>
27   * <p>
28   * The sawtooth function is computed from a base 2 logarithm and fractional parts.
29   * It enhances modules changes with discontinuities and dark rings.
30   * </p>
31   */
32  public class SawToothModuleValue extends DomainColoring {
33  
34      /** Simple constructor.
35       * @param saturation constant saturation
36       */
37      protected SawToothModuleValue(final double saturation) {
38          super(saturation);
39      }
40  
41      /** {@inheritDoc} */
42      @Override
43      public double value(final Complex z) {
44          final double module = z.norm();
45          return FastMath.log(module) / FastMath.log(2.0);
46      }
47  
48  }