mirror of
https://git.dev.opencascade.org/repos/occt.git
synced 2025-04-26 10:19:45 +03:00
100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
// Created on: 2005-12-19
|
|
// Created by: Julia GERASIMOVA
|
|
// Copyright (c) 2005-2014 OPEN CASCADE SAS
|
|
//
|
|
// This file is part of Open CASCADE Technology software library.
|
|
//
|
|
// This library is free software; you can redistribute it and/or modify it under
|
|
// the terms of the GNU Lesser General Public License version 2.1 as published
|
|
// by the Free Software Foundation, with special exception defined in the file
|
|
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
|
|
// distribution for complete text of the license and disclaimer of any warranty.
|
|
//
|
|
// Alternatively, this file may be used under the terms of Open CASCADE
|
|
// commercial license or contractual agreement.
|
|
|
|
|
|
#include <math_Array1OfValueAndWeight.hxx>
|
|
#include <math_ComputeGaussPointsAndWeights.hxx>
|
|
#include <math_EigenValuesSearcher.hxx>
|
|
#include <Standard_ErrorHandler.hxx>
|
|
|
|
#include <algorithm>
|
|
math_ComputeGaussPointsAndWeights::math_ComputeGaussPointsAndWeights(const Standard_Integer Number)
|
|
{
|
|
myIsDone = Standard_False;
|
|
|
|
try {
|
|
myPoints = new TColStd_HArray1OfReal(1, Number);
|
|
myWeights = new TColStd_HArray1OfReal(1, Number);
|
|
|
|
Standard_Integer i;
|
|
|
|
TColStd_Array1OfReal aDiag(1, Number);
|
|
TColStd_Array1OfReal aSubDiag(1, Number);
|
|
|
|
//Initialization of a real symmetric tridiagonal matrix for
|
|
//computation of Gauss quadrature.
|
|
|
|
for (i = 1; i <= Number; i++) {
|
|
aDiag(i) = 0.;
|
|
|
|
if (i == 1)
|
|
aSubDiag(i) = 0.;
|
|
else {
|
|
Standard_Integer sqrIm1 = (i-1)*(i-1);
|
|
aSubDiag(i) = sqrIm1/(4.*sqrIm1 - 1);
|
|
aSubDiag(i) = Sqrt(aSubDiag(i));
|
|
}
|
|
}
|
|
|
|
// Compute eigen values.
|
|
math_EigenValuesSearcher EVsearch(aDiag, aSubDiag);
|
|
|
|
if (EVsearch.IsDone()) {
|
|
math_Array1OfValueAndWeight VWarray(1, Number);
|
|
for (i = 1; i <= Number; i++) {
|
|
math_Vector anEigenVector = EVsearch.EigenVector(i);
|
|
Standard_Real aWeight = anEigenVector(1);
|
|
aWeight = 2. * aWeight * aWeight;
|
|
math_ValueAndWeight EVW( EVsearch.EigenValue(i), aWeight );
|
|
VWarray(i) = EVW;
|
|
}
|
|
|
|
std::sort (VWarray.begin(), VWarray.end());
|
|
|
|
for (i = 1; i <= Number; i++) {
|
|
myPoints->ChangeValue(i) = VWarray(i).Value();
|
|
myWeights->ChangeValue(i) = VWarray(i).Weight();
|
|
}
|
|
myIsDone = Standard_True;
|
|
}
|
|
} catch (Standard_Failure const&) {
|
|
}
|
|
}
|
|
|
|
Standard_Boolean math_ComputeGaussPointsAndWeights::IsDone() const
|
|
{
|
|
return myIsDone;
|
|
}
|
|
|
|
math_Vector math_ComputeGaussPointsAndWeights::Points() const
|
|
{
|
|
Standard_Integer Number = myPoints->Length();
|
|
math_Vector thePoints(1, Number);
|
|
for (Standard_Integer i = 1; i <= Number; i++)
|
|
thePoints(i) = myPoints->Value(i);
|
|
|
|
return thePoints;
|
|
}
|
|
|
|
math_Vector math_ComputeGaussPointsAndWeights::Weights() const
|
|
{
|
|
Standard_Integer Number = myWeights->Length();
|
|
math_Vector theWeights(1, Number);
|
|
for (Standard_Integer i = 1; i <= Number; i++)
|
|
theWeights(i) = myWeights->Value(i);
|
|
|
|
return theWeights;
|
|
}
|