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
  30 namespace chart
  31 {
  32
  33 LogarithmicRegressionCurveCalculator::LogarithmicRegressionCurveCalculator() :
  34         m_fSlope( 0.0 ),
  35         m_fIntercept( 0.0 )
  36 {
  37     ::rtl::math::setNan( & m_fSlope );
  38     ::rtl::math::setNan( & m_fIntercept );
  39 }
  40
  41 LogarithmicRegressionCurveCalculator::~LogarithmicRegressionCurveCalculator()
  42 {}
  43
  44 // ____ XRegressionCurve ____
  45 void SAL_CALL LogarithmicRegressionCurveCalculator::recalculateRegression(
  46     const uno::Sequence< double >& aXValues,
  47     const uno::Sequence< double >& aYValues )
  48     throw (uno::RuntimeException)
  49 {
  50     RegressionCalculationHelper::tDoubleVectorPair aValues(
  51         RegressionCalculationHelper::cleanup(
  52             aXValues, aYValues,
  53             RegressionCalculationHelper::isValidAndXPositive()));
  54
  55     const size_t nMax = aValues.first.size();
  56     if( nMax == 0 )
  57     {
  58         ::rtl::math::setNan( & m_fSlope );
  59         ::rtl::math::setNan( & m_fIntercept );
  60         ::rtl::math::setNan( & m_fCorrelationCoeffitient );
  61         return;
  62     }
  63
  64     double fAverageX = 0.0, fAverageY = 0.0;
  65     size_t i = 0;
  66     for( i = 0; i < nMax; ++i )
  67     {
  68         fAverageX += log( aValues.first[i] );
  69         fAverageY += aValues.second[i];
  70     }
  71
  72     const double fN = static_cast< double >( nMax );
  73     fAverageX /= fN;
  74     fAverageY /= fN;
  75
  76     double fQx = 0.0, fQy = 0.0, fQxy = 0.0;
  77     for( i = 0; i < nMax; ++i )
  78     {
  79         double fDeltaX = log( aValues.first[i] ) - fAverageX;
  80         double fDeltaY = aValues.second[i] - fAverageY;
  81
  82         fQx  += fDeltaX * fDeltaX;
  83         fQy  += fDeltaY * fDeltaY;
  84         fQxy += fDeltaX * fDeltaY;
  85     }
  86
  87     m_fSlope = fQxy / fQx;
  88     m_fIntercept = fAverageY - m_fSlope * fAverageX;
  89     m_fCorrelationCoeffitient = fQxy / sqrt( fQx * fQy );
  90 }
  91
  92 double SAL_CALL LogarithmicRegressionCurveCalculator::getCurveValue( double x )
  93     throw (lang::IllegalArgumentException,
  94            uno::RuntimeException)
  95 {
  96     double fResult;
  97     ::rtl::math::setNan( & fResult );
  98
  99     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
 100             ::rtl::math::isNan( m_fIntercept )))
 101     {
 102         fResult = m_fSlope * log( x ) + m_fIntercept;
 103     }
 104
 105     return fResult;
 106 }
 107
 108 uno::Sequence< geometry::RealPoint2D > SAL_CALL LogarithmicRegressionCurveCalculator::getCurveValues(
 109     double min, double max, ::sal_Int32 nPointCount,
 110     const uno::Reference< chart2::XScaling >& xScalingX,
 111     const uno::Reference< chart2::XScaling >& xScalingY,
 112     ::sal_Bool bMaySkipPointsInCalculation )
 113     throw (lang::IllegalArgumentException,
 114            uno::RuntimeException)
 115 {
 116     if( bMaySkipPointsInCalculation &&
 117         isLogarithmicScaling( xScalingX ) &&
 118         isLinearScaling( xScalingY ))
 119     {
 120         // optimize result
 121         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 122         aResult[0].X = min;
 123         aResult[0].Y = this->getCurveValue( min );
 124         aResult[1].X = max;
 125         aResult[1].Y = this->getCurveValue( max );
 126
 127         return aResult;
 128     }
 129     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 130 }
 131
 132 OUString LogarithmicRegressionCurveCalculator::ImplGetRepresentation(
 133     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 134     ::sal_Int32 nNumberFormatKey ) const
 135 {
 136     OUStringBuffer aBuf( "f(x) = ");
 137
 138     bool bHaveSlope = false;
 139
 140     if( m_fSlope != 0.0 )
 141     {
 142         if( ::rtl::math::approxEqual( fabs( m_fSlope ), 1.0 ))
 143         {
 144             if( m_fSlope < 0 )
 145                 aBuf.append( UC_MINUS_SIGN );
 146         }
 147         else
 148         {
 149             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope ));
 150             aBuf.append( UC_SPACE );
 151         }
 152         aBuf.appendAscii( RTL_CONSTASCII_STRINGPARAM( "ln(x)" ));
 153         bHaveSlope = true;
 154     }
 155
 156     if( bHaveSlope )
 157     {
 158         if( m_fIntercept < 0.0 )
 159         {
 160             aBuf.append( UC_SPACE );
 161             aBuf.append( UC_MINUS_SIGN );
 162             aBuf.append( UC_SPACE );
 163             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs( m_fIntercept )));
 164         }
 165         else if( m_fIntercept > 0.0 )
 166         {
 167             aBuf.appendAscii( RTL_CONSTASCII_STRINGPARAM( " + " ));
 168             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 169         }
 170     }
 171     else
 172     {
 173         aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 174     }
 175
 176     return aBuf.makeStringAndClear();
 177 }
 178
 179 } //  namespace chart
 180
 181 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */