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.algorithmic.forward.functions;
018    
019    import org.apache.commons.nabla.algorithmic.forward.analysis.MethodDifferentiator;
020    import org.apache.commons.nabla.core.DifferentiationException;
021    import org.objectweb.asm.Opcodes;
022    import org.objectweb.asm.tree.InsnList;
023    import org.objectweb.asm.tree.InsnNode;
024    import org.objectweb.asm.tree.MethodInsnNode;
025    import org.objectweb.asm.tree.VarInsnNode;
026    
027    /** Differentiation transformer for the pow function invocation instructions.
028     */
029    public class PowTransformer12 implements MathInvocationTransformer {
030    
031        /** {@inheritDoc} */
032        public InsnList getReplacementList(final String owner, final MethodDifferentiator methodDifferentiator)
033            throws DifferentiationException {
034    
035            // generate differential code
036            // ... a0, a1, b0, b1  --> ... pow(a0,b0), (a1*b0/a0 + b1*log(a0)) * pow(a0,b0)
037            final int tmp1 = methodDifferentiator.getTmp(1);
038            final int tmp2 = methodDifferentiator.getTmp(2);
039            final InsnList list = new InsnList();
040            list.add(new VarInsnNode(Opcodes.DSTORE, tmp1));
041            list.add(new InsnNode(Opcodes.DUP2_X2));
042            list.add(new InsnNode(Opcodes.DMUL));
043            list.add(new VarInsnNode(Opcodes.DSTORE, tmp2));
044            list.add(new InsnNode(Opcodes.DUP2_X2));
045            list.add(new InsnNode(Opcodes.POP2));
046            list.add(new InsnNode(Opcodes.DUP2));
047            list.add(new InsnNode(Opcodes.DUP2));
048            list.add(new MethodInsnNode(Opcodes.INVOKESTATIC, owner, "log", D_RETURN_D_DESCRIPTOR));
049            list.add(new VarInsnNode(Opcodes.DLOAD, tmp1));
050            list.add(new InsnNode(Opcodes.DMUL));
051            list.add(new VarInsnNode(Opcodes.DSTORE, tmp1));
052            list.add(new VarInsnNode(Opcodes.DLOAD, tmp2));
053            list.add(new InsnNode(Opcodes.DUP2_X2));
054            list.add(new InsnNode(Opcodes.POP2));
055            list.add(new InsnNode(Opcodes.DDIV));
056            list.add(new VarInsnNode(Opcodes.DLOAD, tmp1));
057            list.add(new InsnNode(Opcodes.DADD));
058            list.add(new VarInsnNode(Opcodes.DSTORE, tmp1));
059            list.add(new InsnNode(Opcodes.DUP2_X2));
060            list.add(new InsnNode(Opcodes.POP2));
061            list.add(new MethodInsnNode(Opcodes.INVOKESTATIC, owner, "pow", DD_RETURN_D_DESCRIPTOR));
062            list.add(new InsnNode(Opcodes.DUP2));
063            list.add(new VarInsnNode(Opcodes.DLOAD, tmp1));
064            list.add(new InsnNode(Opcodes.DMUL));
065            return list;
066    
067        }
068    
069    }