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
  30 namespace chart
  31 {
  32
  33 PotentialRegressionCurveCalculator::PotentialRegressionCurveCalculator() :
  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 PotentialRegressionCurveCalculator::~PotentialRegressionCurveCalculator()
  42 {}
  43
  44 // ____ XRegressionCurveCalculator ____
  45 void SAL_CALL PotentialRegressionCurveCalculator::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::isValidAndBothPositive()));
  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 += log( 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 = log( 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     m_fIntercept = exp( m_fIntercept );
  92 }
  93
  94 double SAL_CALL PotentialRegressionCurveCalculator::getCurveValue( double x )
  95     throw (lang::IllegalArgumentException,
  96            uno::RuntimeException)
  97 {
  98     double fResult;
  99     ::rtl::math::setNan( & fResult );
 100
 101     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
 102             ::rtl::math::isNan( m_fIntercept )))
 103     {
 104         fResult = m_fIntercept * pow( x, m_fSlope );
 105     }
 106
 107     return fResult;
 108 }
 109
 110 uno::Sequence< geometry::RealPoint2D > SAL_CALL PotentialRegressionCurveCalculator::getCurveValues(
 111     double min, double max, ::sal_Int32 nPointCount,
 112     const uno::Reference< chart2::XScaling >& xScalingX,
 113     const uno::Reference< chart2::XScaling >& xScalingY,
 114     ::sal_Bool bMaySkipPointsInCalculation )
 115     throw (lang::IllegalArgumentException,
 116            uno::RuntimeException)
 117 {
 118     if( bMaySkipPointsInCalculation &&
 119         isLogarithmicScaling( xScalingX ) &&
 120         isLogarithmicScaling( xScalingY ))
 121     {
 122         // optimize result
 123         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 124         aResult[0].X = min;
 125         aResult[0].Y = this->getCurveValue( min );
 126         aResult[1].X = max;
 127         aResult[1].Y = this->getCurveValue( max );
 128
 129         return aResult;
 130     }
 131     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 132 }
 133
 134 OUString PotentialRegressionCurveCalculator::ImplGetRepresentation(
 135     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 136     ::sal_Int32 nNumberFormatKey ) const
 137 {
 138     OUStringBuffer aBuf( "f(x) = ");
 139
 140     if( m_fIntercept == 0.0 )
 141     {
 142         aBuf.append( sal_Unicode( '0' ));
 143     }
 144     else if( m_fSlope == 0.0 )
 145     {
 146         aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 147     }
 148     else
 149     {
 150         if( ! rtl::math::approxEqual( m_fIntercept, 1.0 ) )
 151         {
 152             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 153             aBuf.append( sal_Unicode( ' ' ));
 154         }
 155         if( m_fSlope != 0.0 )
 156         {
 157             aBuf.appendAscii( RTL_CONSTASCII_STRINGPARAM( "x^" ));
 158             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope ));
 159         }
 160     }
 161
 162     return aBuf.makeStringAndClear();
 163 }
 164
 165 } //  namespace chart
 166
 167 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */