001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.nabla.forward.arithmetic;
018
019 import org.apache.commons.nabla.DifferentiationException;
020 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;
021 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;
022 import org.objectweb.asm.Opcodes;
023 import org.objectweb.asm.Type;
024 import org.objectweb.asm.tree.AbstractInsnNode;
025 import org.objectweb.asm.tree.InsnList;
026 import org.objectweb.asm.tree.InsnNode;
027 import org.objectweb.asm.tree.MethodInsnNode;
028
029 /** Differentiation transformer for DDIV instructions.
030 * @version $Id$
031 */
032 public class DDivTransformer implements InstructionsTransformer {
033
034 /** Name of the {@link org.apache.commons.math3.analysis.differentiation.DerivativeStructure} method corresponding to the division. */
035 private static final String DIVIDE_METHOD = "divide";
036
037 /** Name of the {@link org.apache.commons.math3.analysis.differentiation.DerivativeStructure} method corresponding to the reciproval. */
038 private static final String RECIPROCAL_METHOD = "reciprocal";
039
040 /** Name of the {@link org.apache.commons.math3.analysis.differentiation.DerivativeStructure} method corresponding to the multiplication. */
041 private static final String MULTIPLY_METHOD = "multiply";
042
043 /** Indicator for top stack element conversion. */
044 private final boolean stack0Converted;
045
046 /** Indicator for next to top stack element conversion. */
047 private final boolean stack1Converted;
048
049 /** Simple constructor.
050 * @param stack0Converted if true, the top level stack element has already been converted
051 * @param stack1Converted if true, the next to top level stack element has already been converted
052 */
053 public DDivTransformer(final boolean stack0Converted, final boolean stack1Converted) {
054 this.stack0Converted = stack0Converted;
055 this.stack1Converted = stack1Converted;
056 }
057
058 /** {@inheritDoc} */
059 public InsnList getReplacement(final AbstractInsnNode insn,
060 final MethodDifferentiator methodDifferentiator)
061 throws DifferentiationException {
062
063 final InsnList list = new InsnList();
064
065 if (stack1Converted) {
066 if (stack0Converted) {
067 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
068 DIVIDE_METHOD,
069 Type.getMethodDescriptor(DS_TYPE, DS_TYPE)));
070 } else {
071 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
072 DIVIDE_METHOD,
073 Type.getMethodDescriptor(DS_TYPE, Type.DOUBLE_TYPE)));
074 }
075 } else {
076 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
077 RECIPROCAL_METHOD,
078 Type.getMethodDescriptor(DS_TYPE)));
079 list.add(new InsnNode(Opcodes.DUP_X2));
080 list.add(new InsnNode(Opcodes.POP));
081 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
082 MULTIPLY_METHOD,
083 Type.getMethodDescriptor(DS_TYPE, Type.DOUBLE_TYPE)));
084 }
085
086 return list;
087
088 }
089
090 }