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.instructions;
018
019 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
020 import org.apache.commons.nabla.DifferentiationException;
021 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;
022 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;
023 import org.objectweb.asm.Opcodes;
024 import org.objectweb.asm.Type;
025 import org.objectweb.asm.tree.AbstractInsnNode;
026 import org.objectweb.asm.tree.InsnList;
027 import org.objectweb.asm.tree.InsnNode;
028 import org.objectweb.asm.tree.LdcInsnNode;
029 import org.objectweb.asm.tree.MethodInsnNode;
030 import org.objectweb.asm.tree.TypeInsnNode;
031 import org.objectweb.asm.tree.VarInsnNode;
032
033 /** Differentiation transformer for promoting a double on the stack
034 * to a derivative structure.
035 * @version $Id$
036 */
037 public class WideningTransformer implements InstructionsTransformer {
038
039 /** Simple constructor.
040 */
041 public WideningTransformer() {
042 }
043
044 /** {@inheritDoc} */
045 public InsnList getReplacement(final AbstractInsnNode insn,
046 final MethodDifferentiator methodDifferentiator)
047 throws DifferentiationException {
048
049 final InsnList list = new InsnList();
050
051 // copy the instruction creating the double (DCONST_0, DCONST_1, LDC, I2D, L2D or F2D)
052 if (insn.getOpcode() == Opcodes.LDC) {
053 list.add(new LdcInsnNode(((LdcInsnNode) insn).cst));
054 } else {
055 list.add(new InsnNode(insn.getOpcode()));
056 }
057
058 // operand stack initial state: d
059 list.add(new TypeInsnNode(Opcodes.NEW,
060 Type.getInternalName(DerivativeStructure.class))); // => d y_ds
061 list.add(new InsnNode(Opcodes.DUP_X2)); // => y_ds d y_ds
062 list.add(new InsnNode(Opcodes.DUP_X2)); // => y_ds y_ds d y_ds
063 list.add(new InsnNode(Opcodes.POP)); // => y_ds y_ds d
064 list.add(new VarInsnNode(Opcodes.ALOAD, methodDifferentiator.getInputDSIndex())); // => y_ds y_ds d x_ds
065 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,
066 Type.getInternalName(DerivativeStructure.class),
067 "getFreeParameters",
068 Type.getMethodDescriptor(Type.INT_TYPE))); // => y_ds y_ds d params
069 list.add(new VarInsnNode(Opcodes.ALOAD, 1)); // => y_ds y_ds d params x_ds
070 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,
071 Type.getInternalName(DerivativeStructure.class),
072 "getOrder",
073 Type.getMethodDescriptor(Type.INT_TYPE))); // => y_ds y_ds d params order
074 list.add(new InsnNode(Opcodes.DUP2_X2)); // => y_ds y_ds params order d params order
075 list.add(new InsnNode(Opcodes.POP2)); // => y_ds y_ds params order d
076 list.add(new MethodInsnNode(Opcodes.INVOKESPECIAL,
077 Type.getInternalName(DerivativeStructure.class),
078 "<init>",
079 Type.getMethodDescriptor(Type.VOID_TYPE,
080 Type.INT_TYPE,
081 Type.INT_TYPE,
082 Type.DOUBLE_TYPE))); // => y_ds
083
084 return list;
085
086 }
087
088 }