Add abakus

git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/applications/abakus@1071969 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 419 insertions, 0 deletions

diff --git a/src/node.cpp b/src/node.cpp
new file mode 100644
index 0000000..bb49676
--- /dev/null
+++ b/src/node.cpp
@@ -0,0 +1,419 @@
+/*
+ * 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: