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 <RegressionCalculationHelper.hxx>
  22 #include <SpecialCharacters.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     , m_fSign(1.0)
  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 {
  49     RegressionCalculationHelper::tDoubleVectorPair aValues(
  50         RegressionCalculationHelper::cleanup(
  51             aXValues, aYValues,
  52             RegressionCalculationHelper::isValidAndBothPositive()));
  53     m_fSign = 1.0;
  54
  55     size_t nMax = aValues.first.size();
  56     if( nMax <= 1 )  // at least 2 points
  57     {
  58         aValues = RegressionCalculationHelper::cleanup(
  59                     aXValues, aYValues,
  60                     RegressionCalculationHelper::isValidAndXPositiveAndYNegative());
  61         nMax = aValues.first.size();
  62         if( nMax <= 1 )
  63         {
  64             ::rtl::math::setNan( & m_fSlope );
  65             ::rtl::math::setNan( & m_fIntercept );
  66             ::rtl::math::setNan( & m_fCorrelationCoeffitient );
  67             return;
  68         }
  69         m_fSign = -1.0;
  70     }
  71
  72     double fAverageX = 0.0, fAverageY = 0.0;
  73     size_t i = 0;
  74     for( i = 0; i < nMax; ++i )
  75     {
  76         fAverageX += log( aValues.first[i] );
  77         fAverageY += log( m_fSign * aValues.second[i] );
  78     }
  79
  80     const double fN = static_cast< double >( nMax );
  81     fAverageX /= fN;
  82     fAverageY /= fN;
  83
  84     double fQx = 0.0, fQy = 0.0, fQxy = 0.0;
  85     for( i = 0; i < nMax; ++i )
  86     {
  87         double fDeltaX = log( aValues.first[i] ) - fAverageX;
  88         double fDeltaY = log( m_fSign * aValues.second[i] ) - fAverageY;
  89
  90         fQx  += fDeltaX * fDeltaX;
  91         fQy  += fDeltaY * fDeltaY;
  92         fQxy += fDeltaX * fDeltaY;
  93     }
  94
  95     m_fSlope = fQxy / fQx;
  96     m_fIntercept = fAverageY - m_fSlope * fAverageX;
  97     m_fCorrelationCoeffitient = fQxy / sqrt( fQx * fQy );
  98
  99     m_fIntercept = m_fSign * exp( m_fIntercept );
 100 }
 101
 102 double SAL_CALL PotentialRegressionCurveCalculator::getCurveValue( double x )
 103 {
 104     double fResult;
 105     ::rtl::math::setNan( & fResult );
 106
 107     if( ! ( ::rtl::math::isNan( m_fSlope ) ||
 108             ::rtl::math::isNan( m_fIntercept )))
 109     {
 110         fResult = m_fIntercept * pow( x, m_fSlope );
 111     }
 112
 113     return fResult;
 114 }
 115
 116 uno::Sequence< geometry::RealPoint2D > SAL_CALL PotentialRegressionCurveCalculator::getCurveValues(
 117     double min, double max, ::sal_Int32 nPointCount,
 118     const uno::Reference< chart2::XScaling >& xScalingX,
 119     const uno::Reference< chart2::XScaling >& xScalingY,
 120     sal_Bool bMaySkipPointsInCalculation )
 121 {
 122     if( bMaySkipPointsInCalculation &&
 123         isLogarithmicScaling( xScalingX ) &&
 124         isLogarithmicScaling( xScalingY ))
 125     {
 126         // optimize result
 127         uno::Sequence< geometry::RealPoint2D > aResult( 2 );
 128         aResult[0].X = min;
 129         aResult[0].Y = getCurveValue( min );
 130         aResult[1].X = max;
 131         aResult[1].Y = getCurveValue( max );
 132
 133         return aResult;
 134     }
 135     return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
 136 }
 137
 138 OUString PotentialRegressionCurveCalculator::ImplGetRepresentation(
 139     const uno::Reference< util::XNumberFormatter >& xNumFormatter,
 140     sal_Int32 nNumberFormatKey, sal_Int32* pFormulaMaxWidth /* = nullptr */ ) const
 141 {
 142     bool bHasIntercept = !rtl::math::approxEqual( fabs(m_fIntercept), 1.0 );
 143     OUStringBuffer aBuf( mYName + " = " );
 144     sal_Int32 nLineLength = aBuf.getLength();
 145     sal_Int32 nValueLength=0;
 146     if ( pFormulaMaxWidth && *pFormulaMaxWidth > 0 ) // count nValueLength
 147     {
 148         sal_Int32 nCharMin = nLineLength + mXName.getLength() + 3;  // 3 = "^" + 2 extra characters
 149         if ( m_fIntercept != 0.0 && m_fSlope != 0.0 )
 150         {
 151             if ( m_fIntercept < 0.0 )
 152                 nCharMin += 2;  // "- "
 153             if ( bHasIntercept )
 154                 nValueLength = (*pFormulaMaxWidth - nCharMin) / 2;
 155         }
 156         if ( nValueLength == 0 ) // not yet calculated
 157             nValueLength = *pFormulaMaxWidth - nCharMin;
 158         if ( nValueLength <= 0 )
 159             nValueLength = 1;
 160     }
 161
 162     if( m_fIntercept == 0.0 )
 163     {
 164         aBuf.append( '0' );
 165     }
 166     else
 167     {
 168         // temporary buffer
 169         OUStringBuffer aTmpBuf("");
 170         // if nValueLength not calculated then nullptr
 171         sal_Int32* pValueLength = nValueLength ? &nValueLength : nullptr;
 172         if ( m_fIntercept < 0.0 )    // add intercept value
 173              aTmpBuf.append( OUStringChar(aMinusSign) ).append( " " );
 174         if( bHasIntercept )
 175         {
 176             OUString aValueString = getFormattedString( xNumFormatter, nNumberFormatKey, fabs(m_fIntercept), pValueLength );
 177             if ( aValueString != "1" )  // aValueString may be rounded to 1 if nValueLength is small
 178             {
 179                 aTmpBuf.append( aValueString ).append( " " );
 180             }
 181         }
 182         if( m_fSlope != 0.0 )  // add slope value
 183         {
 184             aTmpBuf.append( mXName ).append( "^" );
 185             aTmpBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fSlope, pValueLength ));
 186         }
 187         addStringToEquation( aBuf, nLineLength, aTmpBuf, pFormulaMaxWidth );
 188     }
 189
 190     return aBuf.makeStringAndClear();
 191 }
 192
 193 } //  namespace chart
 194
 195 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */