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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 "ExponentialRegressionCurveCalculator.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 0 : ExponentialRegressionCurveCalculator::ExponentialRegressionCurveCalculator() :
34 : m_fLogSlope( 0.0 ),
35 0 : m_fLogIntercept( 0.0 )
36 : {
37 0 : ::rtl::math::setNan( & m_fLogSlope );
38 0 : ::rtl::math::setNan( & m_fLogIntercept );
39 0 : }
40 :
41 0 : ExponentialRegressionCurveCalculator::~ExponentialRegressionCurveCalculator()
42 0 : {}
43 :
44 : // ____ XRegressionCurveCalculator ____
45 0 : void SAL_CALL ExponentialRegressionCurveCalculator::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 0 : RegressionCalculationHelper::isValidAndYPositive()));
54 :
55 0 : const size_t nMax = aValues.first.size();
56 0 : if( nMax == 0 )
57 : {
58 0 : ::rtl::math::setNan( & m_fLogSlope );
59 0 : ::rtl::math::setNan( & m_fLogIntercept );
60 0 : ::rtl::math::setNan( & m_fCorrelationCoeffitient );// actual it is coefficient of determination
61 0 : return;
62 : }
63 :
64 0 : double fAverageX = 0.0, fAverageY = 0.0;
65 0 : size_t i = 0;
66 0 : for( i = 0; i < nMax; ++i )
67 : {
68 0 : fAverageX += aValues.first[i];
69 0 : fAverageY += log( aValues.second[i] );
70 : }
71 :
72 0 : const double fN = static_cast< double >( nMax );
73 0 : fAverageX /= fN;
74 0 : fAverageY /= fN;
75 :
76 0 : double fQx = 0.0, fQy = 0.0, fQxy = 0.0;
77 0 : for( i = 0; i < nMax; ++i )
78 : {
79 0 : double fDeltaX = aValues.first[i] - fAverageX;
80 0 : double fDeltaY = log( aValues.second[i] ) - fAverageY;
81 :
82 0 : fQx += fDeltaX * fDeltaX;
83 0 : fQy += fDeltaY * fDeltaY;
84 0 : fQxy += fDeltaX * fDeltaY;
85 : }
86 :
87 0 : m_fLogSlope = fQxy / fQx;
88 0 : m_fLogIntercept = fAverageY - m_fLogSlope * fAverageX;
89 0 : m_fCorrelationCoeffitient = fQxy / sqrt( fQx * fQy );
90 :
91 : }
92 :
93 0 : double SAL_CALL ExponentialRegressionCurveCalculator::getCurveValue( double x )
94 : throw (lang::IllegalArgumentException,
95 : uno::RuntimeException)
96 : {
97 : double fResult;
98 0 : ::rtl::math::setNan( & fResult );
99 :
100 0 : if( ! ( ::rtl::math::isNan( m_fLogSlope ) ||
101 0 : ::rtl::math::isNan( m_fLogIntercept )))
102 : {
103 0 : fResult = exp(m_fLogIntercept + x * m_fLogSlope);
104 : }
105 :
106 0 : return fResult;
107 : }
108 :
109 0 : uno::Sequence< geometry::RealPoint2D > SAL_CALL ExponentialRegressionCurveCalculator::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)
116 : {
117 0 : if( bMaySkipPointsInCalculation &&
118 0 : isLinearScaling( xScalingX ) &&
119 0 : isLogarithmicScaling( xScalingY ))
120 : {
121 : // optimize result
122 0 : uno::Sequence< geometry::RealPoint2D > aResult( 2 );
123 0 : aResult[0].X = min;
124 0 : aResult[0].Y = this->getCurveValue( min );
125 0 : aResult[1].X = max;
126 0 : aResult[1].Y = this->getCurveValue( max );
127 :
128 0 : return aResult;
129 : }
130 :
131 0 : return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
132 : }
133 :
134 :
135 0 : OUString ExponentialRegressionCurveCalculator::ImplGetRepresentation(
136 : const uno::Reference< util::XNumberFormatter >& xNumFormatter,
137 : ::sal_Int32 nNumberFormatKey ) const
138 : {
139 0 : double fIntercept = exp(m_fLogIntercept);
140 0 : double fSlope = exp(m_fLogSlope);
141 0 : bool bHasSlope = !rtl::math::approxEqual( fSlope, 1.0 );
142 0 : bool bHasIntercept = !rtl::math::approxEqual( fIntercept, 1.0 );
143 :
144 0 : OUStringBuffer aBuf( "f(x) = ");
145 :
146 0 : if ( fIntercept == 0.0)
147 : {
148 : // underflow, a true zero is impossible
149 0 : aBuf.append( "exp( ");
150 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogIntercept) );
151 0 : aBuf.append( (m_fLogSlope < 0.0) ? " - " : " + ");
152 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs(m_fLogSlope)) );
153 0 : aBuf.append( " x )");
154 : }
155 : else
156 : {
157 0 : if (bHasIntercept)
158 : {
159 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fIntercept) );
160 0 : aBuf.append( " exp( ");
161 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogSlope) );
162 0 : aBuf.append( " x )");
163 : }
164 : else
165 : {
166 : // show logarithmic output, if intercept and slope both are near one
167 : // otherwise drop output of intercept, which is 1 here
168 0 : aBuf.append( " exp( ");
169 0 : if (!bHasSlope)
170 : {
171 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogIntercept) );
172 0 : aBuf.append( (m_fLogSlope < 0.0) ? " - " : " + ");
173 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs(m_fLogSlope)) );
174 : }
175 : else
176 : {
177 0 : aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogSlope) );
178 : }
179 0 : aBuf.append( " x )");
180 : }
181 : }
182 :
183 0 : return aBuf.makeStringAndClear();
184 : }
185 :
186 : } // namespace chart
187 :
188 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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