chart2/source/tools/LogarithmicRegressionCurveCalculator.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include "LogarithmicRegressionCurveCalculator.hxx"
  21 #include "macros.hxx"
  22 #include "RegressionCalculationHelper.hxx"
  23
  24 #include <rtl/math.hxx>
  25 #include <rtl/ustrbuf.hxx>
  26
  27 using namespace ::com::sun::star;
  28
  29 namespace chart
  30 {
  31
  32 LogarithmicRegressionCurveCalculator::LogarithmicRegressionCurveCalculator() :
  33         m_fSlope( 0.0 ),
  34         m_fIntercept( 0.0 )
  35 {
  36     ::rtl::math::setNan( & m_fSlope );
  37     ::rtl::math::setNan( & m_fIntercept );
  38 }
  39
  40 LogarithmicRegressionCurveCalculator::~LogarithmicRegressionCurveCalculator()
  41 {}
  42
  43 // ____ XRegressionCurve ____
  44 void SAL_CALL LogarithmicRegressionCurveCalculator::recalculateRegression(
  45     const uno::Sequence< double >& aXValues,
  46     const uno::Sequence< double >& aYValues )
  47     throw (uno::RuntimeException, std::exception)
  48 {
  49     RegressionCalculationHelper::tDoubleVectorPair aValues(
  50         RegressionCalculationHelper::cleanup(
  51             aXValues, aYValues,
  52             RegressionCalculationHelper::isValidAndXPositive()));
  53
  54     const size_t nMax = aValues.first.size();
  55     if( nMax == 0 )
  56     {
  57         ::rtl::math::setNan( & m_fSlope );
  58         ::rtl::math::setNan( & m_fIntercept );
  59         ::rtl::math::setNan( & m_fCorrelationCoeffitient );
  60         return;
  61     }
  62
  63     double fAverageX = 0.0, fAverageY = 0.0;
  64     size_t i = 0;
  65     for( i = 0; i < nMax; ++i )
  66     {
  67         fAverageX += log( aValues.first[i] );
  68         fAverageY += aValues.second[i];
  69     }
  70
  71     const double fN = static_cast< double >( nMax );
  72     fAverageX /= fN;
  73     fAverageY /= fN;
  74
  75     double fQx = 0.0, fQy = 0.0, fQxy = 0.0;
  76     for( i = 0; i < nMax; ++i )
  77     {
  78         double fDeltaX = log( aValues.first[i] ) - fAverageX;
  79         double fDeltaY = aValues.second[i] - fAverageY;
  80
  81         fQx  += fDeltaX * fDeltaX;
  82         fQy  += fDeltaY * fDeltaY;
  83         fQxy += fDeltaX * fDeltaY;
  84     }
  85
  86     m_fSlope = fQxy / fQx;
  87     m_fIntercept = fAverageY - m_fSlope * fAverageX;
  88     m_fCorrelationCoeffitient = fQxy / sqrt( fQx * fQy );
  89 }
  90
  91 double SAL_CALL LogarithmicRegressionCurveCalculator::getCurveValue( double x )
  92     throw (lang::IllegalArgumentException,
  93            uno::RuntimeException, std::exception)
  94 {
  95     double fResult;
  96     ::rtl::math::setNan( & fResult );
  97
  98     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
  99             ::rtl::math::isNan( m_fIntercept )))
 100     {
 101         fResult = m_fSlope * log( x ) + m_fIntercept;
 102     }
 103
 104     return fResult;
 105 }
 106
 107 uno::Sequence< geometry::RealPoint2D > SAL_CALL LogarithmicRegressionCurveCalculator::getCurveValues(
 108     double min, double max, ::sal_Int32 nPointCount,
 109     const uno::Reference< chart2::XScaling >& xScalingX,
 110     const uno::Reference< chart2::XScaling >& xScalingY,
 111     sal_Bool bMaySkipPointsInCalculation )
 112     throw (lang::IllegalArgumentException,
 113            uno::RuntimeException, std::exception)
 114 {
 115     if( bMaySkipPointsInCalculation &&
 116         isLogarithmicScaling( xScalingX ) &&
 117         isLinearScaling( xScalingY ))
 118     {
 119         // optimize result
 120         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 121         aResult[0].X = min;
 122         aResult[0].Y = this->getCurveValue( min );
 123         aResult[1].X = max;
 124         aResult[1].Y = this->getCurveValue( max );
 125
 126         return aResult;
 127     }
 128     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 129 }
 130
 131 OUString LogarithmicRegressionCurveCalculator::ImplGetRepresentation(
 132     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 133     ::sal_Int32 nNumberFormatKey ) const
 134 {
 135     OUStringBuffer aBuf( "f(x) = ");
 136
 137     bool bHaveSlope = false;
 138
 139     if( m_fSlope != 0.0 )
 140     {
 141         if( ::rtl::math::approxEqual( fabs( m_fSlope ), 1.0 ))
 142         {
 143             if( m_fSlope < 0 )
 144                 aBuf.append( UC_MINUS_SIGN );
 145         }
 146         else
 147         {
 148             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope ));
 149             aBuf.append( UC_SPACE );
 150         }
 151         aBuf.append( "ln(x)" );
 152         bHaveSlope = true;
 153     }
 154
 155     if( bHaveSlope )
 156     {
 157         if( m_fIntercept < 0.0 )
 158         {
 159             aBuf.append( UC_SPACE );
 160             aBuf.append( UC_MINUS_SIGN );
 161             aBuf.append( UC_SPACE );
 162             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs( m_fIntercept )));
 163         }
 164         else if( m_fIntercept > 0.0 )
 165         {
 166             aBuf.append( " + " );
 167             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 168         }
 169     }
 170     else
 171     {
 172         aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 173     }
 174
 175     return aBuf.makeStringAndClear();
 176 }
 177
 178 } //  namespace chart
 179
 180 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */