chart2/source/tools/PotentialRegressionCurveCalculator.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 "PotentialRegressionCurveCalculator.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 PotentialRegressionCurveCalculator::PotentialRegressionCurveCalculator() :
  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 PotentialRegressionCurveCalculator::~PotentialRegressionCurveCalculator()
  41 {}
  42
  43 // ____ XRegressionCurveCalculator ____
  44 void SAL_CALL PotentialRegressionCurveCalculator::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::isValidAndBothPositive()));
  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 += log( 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 = log( 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     m_fIntercept = exp( m_fIntercept );
  91 }
  92
  93 double SAL_CALL PotentialRegressionCurveCalculator::getCurveValue( double x )
  94     throw (lang::IllegalArgumentException,
  95            uno::RuntimeException, std::exception)
  96 {
  97     double fResult;
  98     ::rtl::math::setNan( & fResult );
  99
 100     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
 101             ::rtl::math::isNan( m_fIntercept )))
 102     {
 103         fResult = m_fIntercept * pow( x, m_fSlope );
 104     }
 105
 106     return fResult;
 107 }
 108
 109 uno::Sequence< geometry::RealPoint2D > SAL_CALL PotentialRegressionCurveCalculator::getCurveValues(
 110     double min, double max, ::sal_Int32 nPointCount,
 111     const uno::Reference< chart2::XScaling >& xScalingX,
 112     const uno::Reference< chart2::XScaling >& xScalingY,
 113     sal_Bool bMaySkipPointsInCalculation )
 114     throw (lang::IllegalArgumentException,
 115            uno::RuntimeException, std::exception)
 116 {
 117     if( bMaySkipPointsInCalculation &&
 118         isLogarithmicScaling( xScalingX ) &&
 119         isLogarithmicScaling( xScalingY ))
 120     {
 121         // optimize result
 122         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 123         aResult[0].X = min;
 124         aResult[0].Y = this->getCurveValue( min );
 125         aResult[1].X = max;
 126         aResult[1].Y = this->getCurveValue( max );
 127
 128         return aResult;
 129     }
 130     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 131 }
 132
 133 OUString PotentialRegressionCurveCalculator::ImplGetRepresentation(
 134     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 135     ::sal_Int32 nNumberFormatKey ) const
 136 {
 137     OUStringBuffer aBuf( "f(x) = ");
 138
 139     if( m_fIntercept == 0.0 )
 140     {
 141         aBuf.append( '0');
 142     }
 143     else if( m_fSlope == 0.0 )
 144     {
 145         aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 146     }
 147     else
 148     {
 149         if( ! rtl::math::approxEqual( m_fIntercept, 1.0 ) )
 150         {
 151             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 152             aBuf.append( ' ');
 153         }
 154         if( m_fSlope != 0.0 )
 155         {
 156             aBuf.append( "x^" );
 157             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope ));
 158         }
 159     }
 160
 161     return aBuf.makeStringAndClear();
 162 }
 163
 164 } //  namespace chart
 165
 166 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */