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.objectweb.asm.Opcodes;
021    import org.objectweb.asm.tree.InsnList;
022    import org.objectweb.asm.tree.InsnNode;
023    import org.objectweb.asm.tree.LdcInsnNode;
024    import org.objectweb.asm.tree.MethodInsnNode;
025    
026    /** Differentiation transformer for the cbrt function invocation instructions.
027     */
028    public class CbrtTransformer implements MathInvocationTransformer {
029    
030        /** {@inheritDoc} */
031        public InsnList getReplacementList(final String owner, final MethodDifferentiator methodDifferentiator) {
032    
033            // generate differential code
034            // ... u0, u1  --> ... cbrt(u0), u1 / (3 * cbrt(u0) * cbrt(u0))
035            final InsnList list = new InsnList();
036            list.add(new InsnNode(Opcodes.DUP2_X2));
037            list.add(new InsnNode(Opcodes.POP2));
038            list.add(new MethodInsnNode(Opcodes.INVOKESTATIC, owner, "cbrt", D_RETURN_D_DESCRIPTOR));
039            list.add(new InsnNode(Opcodes.DUP2_X2));
040            list.add(new InsnNode(Opcodes.DUP2));
041            list.add(new InsnNode(Opcodes.DMUL));
042            list.add(new LdcInsnNode(Double.valueOf(3)));
043            list.add(new InsnNode(Opcodes.DMUL));
044            list.add(new InsnNode(Opcodes.DDIV));
045            return list;
046    
047        }
048    }