code: ///////////////////////////////////////////////////////////////////////////
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  //                  / /   ____  ____ _(_)____/ | / / ____/               //
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  //                                                                       //
  //               The Next Generation Logic Library                       //
  //                                                                       //
  ///////////////////////////////////////////////////////////////////////////
  //                                                                       //
  //  Copyright 2015-20xx Christoph Zengler                                //
  //                                                                       //
  //  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.logicng.transformations.dnf;
  
  import org.logicng.formulas.Formula;
  import org.logicng.formulas.FormulaFactory;
  import org.logicng.knowledgecompilation.bdds.jbuddy.BDDKernel;
  import org.logicng.transformations.BDDNormalFormTransformation;
  
  /**
   * Transformation of a formula in DNF by converting it to a BDD.
   * @version 2.3.0
   * @since 2.3.0
   */
  public final class BDDDNFTransformation extends BDDNormalFormTransformation {
  
      /**
       * Constructs a new BDD-based DNF transformation with an optional BDD kernel.
       * <p>
       * Warning: You can use this object for arbitrarily many transformations, <b>but</b>
       * the number of different variables in all applied formulas <b>must not exceed</b>
       * the number of variables in the kernel.
       * @param kernel the optional BDD kernel
       */
      public BDDDNFTransformation(final BDDKernel kernel) {
          super(kernel);
      }
  
      /**
       * Constructs a new BDD-based DNF transformation for a given number of variables.
       * <p>
       * Warning: You can use this object for arbitrarily many transformations, <b>but</b>
       * the number of different variables in all applied formulas <b>must not exceed</b>
       * {@code numVars}.
       * <p>
       * To improve performance you might want to use {@link #BDDDNFTransformation(BDDKernel)},
       * where you have full control over the node and cache size in the used BDD kernel.
       * @param f       the formula factory to use
       * @param numVars the number of variables
       */
      public BDDDNFTransformation(final FormulaFactory f, final int numVars) {
          super(f, numVars);
      }
  
      /**
       * Constructs a new BDD-based DNF transformation and constructs a new BDD kernel
       * for every formula application.
       */
      public BDDDNFTransformation() {
          this(null);
      }
  
      @Override
      public Formula apply(final Formula formula, final boolean cache) {
          return compute(formula, false, cache);
      }
  }
  