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.MethodInsnNode; 024 025 /** Differentiation transformer for the sqrt function invocation instructions. 026 */ 027 public class SqrtTransformer implements MathInvocationTransformer { 028 029 /** {@inheritDoc} */ 030 public InsnList getReplacementList(final String owner, final MethodDifferentiator methodDifferentiator) { 031 032 // generate differential code 033 // ... u0, u1 --> ... sqrt(u0), u1 / (2 * sqrt(u0)) 034 final InsnList list = new InsnList(); 035 list.add(new InsnNode(Opcodes.DUP2_X2)); 036 list.add(new InsnNode(Opcodes.POP2)); 037 list.add(new MethodInsnNode(Opcodes.INVOKESTATIC, owner, "sqrt", D_RETURN_D_DESCRIPTOR)); 038 list.add(new InsnNode(Opcodes.DUP2_X2)); 039 list.add(new InsnNode(Opcodes.DUP2)); 040 list.add(new InsnNode(Opcodes.DADD)); 041 list.add(new InsnNode(Opcodes.DDIV)); 042 return list; 043 044 } 045 }