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diff --git a/src/node.cpp b/src/node.cpp
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+/*
+ * node.cpp - part of abakus
+ * Copyright (C) 2004, 2005 Michael Pyne <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02110-1301 USA
+ */
+#include <kdebug.h>
+
+#include <math.h>
+
+#include "node.h"
+#include "valuemanager.h"
+#include "function.h"
+
+void Node::deleteNode(Node *node)
+{
+ if(dynamic_cast<BaseFunction *>(node) != 0)
+ delete node;
+}
+
+BaseFunction::BaseFunction(const char *name) :
+ m_name(name)
+{
+}
+
+const Function *BaseFunction::function() const
+{
+ return FunctionManager::instance()->function(m_name);
+}
+
+UnaryFunction::UnaryFunction(const char *name, Node *operand) :
+ BaseFunction(name), m_node(operand)
+{
+}
+
+UnaryFunction::~UnaryFunction()
+{
+ deleteNode(m_node);
+ m_node = 0;
+}
+
+void UnaryFunction::setOperand(Node *operand)
+{
+ m_node = operand;
+}
+
+void UnaryFunction::applyMap(NodeFunctor &fn) const
+{
+ fn(operand());
+ fn(this);
+}
+
+QString UnaryFunction::infixString() const
+{
+ return QString("%1(%2)").arg(name(), operand()->infixString());
+}
+
+BuiltinFunction::BuiltinFunction(const char *name, Node *operand) :
+ UnaryFunction(name, operand)
+{
+}
+
+Abakus::number_t BuiltinFunction::value() const
+{
+ if(function() && operand()) {
+ Abakus::number_t fnValue = operand()->value();
+ return evaluateFunction(function(), fnValue);
+ }
+
+ return Abakus::number_t(0);
+}
+
+Abakus::number_t BuiltinFunction::derivative() const
+{
+ Abakus::number_t du = operand()->derivative();
+ Abakus::number_t value = operand()->value();
+ Abakus::number_t one(1), zero(0);
+
+ if(du == zero)
+ return du;
+
+ // In case these functions get added later, these derivatives may
+ // be useful:
+ // d/dx(asinh u) = (du/dx * 1 / sqrt(x^2 + 1))
+ // d/dx(acosh u) = (du/dx * 1 / sqrt(x^2 - 1))
+ // d/dx(atanh u) = (du/dx * 1 / (1 - x^2))
+
+ // This is very unfortunate duplication.
+ if(name() == "sin")
+ return value.cos() * du;
+ else if(name() == "cos")
+ return -value.sin() * du;
+ else if(name() == "tan") {
+ Abakus::number_t cosResult;
+
+ cosResult = value.cos();
+ cosResult = cosResult * cosResult;
+ return one / cosResult;
+ }
+ else if(name() == "asinh") {
+ value = value * value + one;
+ return du / value.sqrt();
+ }
+ else if(name() == "acosh") {
+ value = value * value - one;
+ return du / value.sqrt();
+ }
+ else if(name() == "atanh") {
+ value = one - value * value;
+ return du / value;
+ }
+ else if(name() == "sinh") {
+ return du * value.cosh();
+ }
+ else if(name() == "cosh") {
+ return du * value.sinh(); // Yes the sign is correct.
+ }
+ else if(name() == "tanh") {
+ Abakus::number_t tanh = value.tanh();
+
+ return du * (one - tanh * tanh);
+ }
+ else if(name() == "atan") {
+ return one * du / (one + value * value);
+ }
+ else if(name() == "acos") {
+ // Same as asin but with inverted sign.
+ return -(one / (value * value - one).sqrt() * du);
+ }
+ else if(name() == "asin") {
+ return one / (value * value - one).sqrt() * du;
+ }
+ else if(name() == "ln") {
+ return du / value;
+ }
+ else if(name() == "exp") {
+ return du * value.exp();
+ }
+ else if(name() == "log") {
+ return du / value / Abakus::number_t(10).ln();
+ }
+ else if(name() == "sqrt") {
+ Abakus::number_t half("0.5");
+ return half * value.pow(-half) * du;
+ }
+ else if(name() == "abs") {
+ return (value / value.abs()) * du;
+ }
+
+ // Approximate it.
+
+ Abakus::number_t epsilon("1e-15");
+ Abakus::number_t fxh = evaluateFunction(function(), value + epsilon);
+ Abakus::number_t fx = evaluateFunction(function(), value);
+ return (fxh - fx) / epsilon;
+}
+
+DerivativeFunction::~DerivativeFunction()
+{
+ deleteNode(m_operand);
+ m_operand = 0;
+}
+
+Abakus::number_t DerivativeFunction::value() const
+{
+ ValueManager *vm = ValueManager::instance();
+ Abakus::number_t result;
+
+ if(vm->isValueSet("x")) {
+ Abakus::number_t oldValue = vm->value("x");
+
+ vm->setValue("x", m_where->value());
+ result = m_operand->derivative();
+ vm->setValue("x", oldValue);
+ }
+ else {
+ vm->setValue("x", m_where->value());
+ result = m_operand->derivative();
+ vm->removeValue("x");
+ }
+
+ return result;
+}
+
+Abakus::number_t DerivativeFunction::derivative() const
+{
+ kdError() << k_funcinfo << endl;
+ kdError() << "This function is never supposed to be called!\n";
+
+ return m_operand->derivative();
+}
+
+void DerivativeFunction::applyMap(NodeFunctor &fn) const
+{
+ fn(m_operand);
+ fn(this);
+}
+
+QString DerivativeFunction::infixString() const
+{
+ return QString("deriv(%1, %2)").arg(m_operand->infixString(), m_where->infixString());
+}
+
+UnaryOperator::UnaryOperator(Type type, Node *operand)
+ : m_type(type), m_node(operand)
+{
+}
+
+UnaryOperator::~UnaryOperator()
+{
+ deleteNode(m_node);
+ m_node = 0;
+}
+
+void UnaryOperator::applyMap(NodeFunctor &fn) const
+{
+ fn(operand());
+ fn(this);
+}
+
+QString UnaryOperator::infixString() const
+{
+ if(dynamic_cast<BinaryOperator *>(operand()))
+ return QString("-(%1)").arg(operand()->infixString());
+
+ return QString("-%1").arg(operand()->infixString());
+}
+
+Abakus::number_t UnaryOperator::derivative() const
+{
+ switch(type()) {
+ case Negation:
+ return -(operand()->derivative());
+
+ default:
+ kdError() << "Impossible case encountered for UnaryOperator!\n";
+ return Abakus::number_t(0);
+ }
+}
+
+Abakus::number_t UnaryOperator::value() const
+{
+ switch(type()) {
+ case Negation:
+ return -(operand()->value());
+
+ default:
+ kdError() << "Impossible case encountered for UnaryOperator!\n";
+ return Abakus::number_t(0);
+ }
+}
+
+BinaryOperator::BinaryOperator(Type type, Node *left, Node *right) :
+ m_type(type), m_left(left), m_right(right)
+{
+}
+
+BinaryOperator::~BinaryOperator()
+{
+ deleteNode(m_left);
+ m_left = 0;
+
+ deleteNode(m_right);
+ m_right = 0;
+}
+
+void BinaryOperator::applyMap(NodeFunctor &fn) const
+{
+ fn(leftNode());
+ fn(rightNode());
+ fn(this);
+}
+
+QString BinaryOperator::infixString() const
+{
+ QString op;
+
+ switch(type()) {
+ case Addition:
+ op = "+";
+ break;
+
+ case Subtraction:
+ op = "-";
+ break;
+
+ case Multiplication:
+ op = "*";
+ break;
+
+ case Division:
+ op = "/";
+ break;
+
+ case Exponentiation:
+ op = "^";
+ break;
+
+ default:
+ op = "Error";
+ }
+
+ QString left = QString(isSimpleNode(leftNode()) ? "%1" : "(%1)").arg(leftNode()->infixString());
+ QString right = QString(isSimpleNode(rightNode()) ? "%1" : "(%1)").arg(rightNode()->infixString());
+
+ return QString("%1 %2 %3").arg(left, op, right);
+}
+
+Abakus::number_t BinaryOperator::derivative() const
+{
+ if(!leftNode() || !rightNode()) {
+ kdError() << "Can't evaluate binary operator!\n";
+ return Abakus::number_t(0);
+ }
+
+ Abakus::number_t f = leftNode()->value();
+ Abakus::number_t fPrime = leftNode()->derivative();
+ Abakus::number_t g = rightNode()->value();
+ Abakus::number_t gPrime = rightNode()->derivative();
+
+ switch(type()) {
+ case Addition:
+ return fPrime + gPrime;
+
+ case Subtraction:
+ return fPrime - gPrime;
+
+ case Multiplication:
+ return f * gPrime + fPrime * g;
+
+ case Division:
+ return (g * fPrime - f * gPrime) / (g * g);
+
+ case Exponentiation:
+ return f.pow(g) * ((g / f) * fPrime + gPrime * f.ln());
+
+ default:
+ kdError() << "Impossible case encountered evaluating binary operator!\n";
+ return Abakus::number_t(0);
+ }
+}
+
+Abakus::number_t BinaryOperator::value() const
+{
+ if(!leftNode() || !rightNode()) {
+ kdError() << "Can't evaluate binary operator!\n";
+ return Abakus::number_t(0);
+ }
+
+ Abakus::number_t lValue = leftNode()->value();
+ Abakus::number_t rValue = rightNode()->value();
+
+ switch(type()) {
+ case Addition:
+ return lValue + rValue;
+
+ case Subtraction:
+ return lValue - rValue;
+
+ case Multiplication:
+ return lValue * rValue;
+
+ case Division:
+ return lValue / rValue;
+
+ case Exponentiation:
+ return lValue.pow(rValue);
+
+ default:
+ kdError() << "Impossible case encountered evaluating binary operator!\n";
+ return Abakus::number_t(0);
+ }
+}
+
+bool BinaryOperator::isSimpleNode(Node *node) const
+{
+ if(dynamic_cast<Identifier *>(node) ||
+ dynamic_cast<NumericValue *>(node) ||
+ dynamic_cast<UnaryOperator *>(node) ||
+ dynamic_cast<BaseFunction *>(node))
+ {
+ return true;
+ }
+
+ return false;
+}
+
+Identifier::Identifier(const char *name) : m_name(name)
+{
+}
+
+Abakus::number_t Identifier::value() const
+{
+ return ValueManager::instance()->value(name());
+}
+
+void Identifier::applyMap(NodeFunctor &fn) const
+{
+ fn(this);
+}
+
+QString NumericValue::infixString() const
+{
+ return value().toString();
+}
+
+// vim: set et ts=8 sw=4:
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-23 13:23:22 +0000