chart2/source/tools/LinearRegressionCurveCalculator.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 "LinearRegressionCurveCalculator.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 LinearRegressionCurveCalculator::LinearRegressionCurveCalculator() :
  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 LinearRegressionCurveCalculator::~LinearRegressionCurveCalculator()
  42 {}
  43
  44 // ____ XRegressionCurveCalculator ____
  45 void SAL_CALL LinearRegressionCurveCalculator::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::isValid()));
  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     const double fN = static_cast< double >( nMax );
  65     double fSumX = 0.0, fSumY = 0.0, fSumXSq = 0.0, fSumYSq = 0.0, fSumXY = 0.0;
  66     for( size_t i = 0; i < nMax; ++i )
  67     {
  68         fSumX   += aValues.first[i];
  69         fSumY   += aValues.second[i];
  70         fSumXSq += aValues.first[i]  * aValues.first[i];
  71         fSumYSq += aValues.second[i] * aValues.second[i];
  72         fSumXY  += aValues.first[i]  * aValues.second[i];
  73     }
  74
  75     m_fSlope = (fN * fSumXY - fSumX * fSumY) / ( fN * fSumXSq - fSumX * fSumX );
  76     m_fIntercept = (fSumY - m_fSlope * fSumX) / fN;
  77
  78     m_fCorrelationCoeffitient = ( fN * fSumXY - fSumX * fSumY ) /
  79         sqrt( ( fN * fSumXSq - fSumX * fSumX ) *
  80               ( fN * fSumYSq - fSumY * fSumY ) );
  81 }
  82
  83 double SAL_CALL LinearRegressionCurveCalculator::getCurveValue( double x )
  84     throw (lang::IllegalArgumentException,
  85            uno::RuntimeException)
  86 {
  87     double fResult;
  88     ::rtl::math::setNan( & fResult );
  89
  90     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
  91             ::rtl::math::isNan( m_fIntercept )))
  92     {
  93         fResult = m_fSlope * x + m_fIntercept;
  94     }
  95
  96     return fResult;
  97 }
  98
  99 uno::Sequence< geometry::RealPoint2D > SAL_CALL LinearRegressionCurveCalculator::getCurveValues(
 100     double min, double max, ::sal_Int32 nPointCount,
 101     const uno::Reference< chart2::XScaling >& xScalingX,
 102     const uno::Reference< chart2::XScaling >& xScalingY,
 103     ::sal_Bool bMaySkipPointsInCalculation )
 104     throw (lang::IllegalArgumentException,
 105            uno::RuntimeException)
 106 {
 107     if( bMaySkipPointsInCalculation &&
 108         isLinearScaling( xScalingX ) &&
 109         isLinearScaling( xScalingY ))
 110     {
 111         // optimize result
 112         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 113         aResult[0].X = min;
 114         aResult[0].Y = this->getCurveValue( min );
 115         aResult[1].X = max;
 116         aResult[1].Y = this->getCurveValue( max );
 117
 118         return aResult;
 119     }
 120     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 121 }
 122
 123 OUString LinearRegressionCurveCalculator::ImplGetRepresentation(
 124     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 125     ::sal_Int32 nNumberFormatKey ) const
 126 {
 127     OUStringBuffer aBuf( "f(x) = ");
 128
 129     bool bHaveSlope = false;
 130
 131     if( m_fSlope != 0.0 )
 132     {
 133         if( ::rtl::math::approxEqual( fabs( m_fSlope ), 1.0 ))
 134         {
 135             if( m_fSlope < 0 )
 136                 aBuf.append( UC_MINUS_SIGN );
 137         }
 138         else
 139             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope ));
 140         aBuf.append( sal_Unicode( 'x' ));
 141         bHaveSlope = true;
 142     }
 143
 144     if( bHaveSlope )
 145     {
 146         if( m_fIntercept < 0.0 )
 147         {
 148             aBuf.append( UC_SPACE );
 149             aBuf.append( UC_MINUS_SIGN );
 150             aBuf.append( UC_SPACE );
 151             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs( m_fIntercept )));
 152         }
 153         else if( m_fIntercept > 0.0 )
 154         {
 155             aBuf.appendAscii( RTL_CONSTASCII_STRINGPARAM( " + " ));
 156             aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 157         }
 158     }
 159     else
 160     {
 161         aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fIntercept ));
 162     }
 163
 164     return aBuf.makeStringAndClear();
 165 }
 166
 167 } //  namespace chart
 168
 169 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */