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kernel.h
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1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 // File kernel.h
4 //
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7 // The MIT License
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9 // Copyright (c) 2006 Scientific Computing and Imaging Institute,
10 // University of Utah (USA) and Department of Aeronautics, Imperial
11 // College London (UK).
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31 //
32 // Description:
33 //
34 ///////////////////////////////////////////////////////////////////////////////
35 
36 #ifndef NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H
37 #define NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H
38 
42 
43 namespace Nektar
44 {
45  namespace LibUtilities
46  {
47  class Kernel
48  {
49  public:
50  /**
51  * \brief The default constructor
52  */
54 
55  LIB_UTILITIES_EXPORT Kernel(int order);
56 
57  /**
58  * \brief The default destructor
59  */
60  //~Kernel();
61 
62  /**
63  * \brief This funciton updates the bspline to the appropriate order.
64  */
66 
67  /**
68  * \brief This funciton updates the kernel coefficients.
69  */
71 
72  /**
73  * \brief This funciton updates the kernel breaks.
74  * \param h represents the mesh spacing
75  */
77 
78  /**
79  * \brief This funciton returns a 2D array representing the bspline
80  * of the appropriate order.
81  */
82  Array<TwoD,NekDouble> GetKernelBspline()
83  {
84  return b_spline;
85  }
86 
87  /**
88  * \brief This funciton returns a 1D array representing the kernel coefficients
89  */
90  Array<OneD,NekDouble> GetKernelCoeffs()
91  {
92  return k_coeffs;
93  }
94 
95  /**
96  * \brief This funciton returns a 1D array representing the kernel breaks
97  */
98  Array<OneD,NekDouble> GetKernelBreaks()
99  {
100  return k_breaks;
101  }
102 
103  /**
104  * \brief This funciton sets the k_order variable
105  */
106  void UpdateKernelOrder(int order)
107  {
108  k_order = order;
109  }
110 
111  /**
112  * \brief This funciton sets the k_ncoeffs variable
113  */
115  {
116  k_ncoeffs = 2*(k_order-1)+1;
117  }
118 
119  /**
120  * \brief This funciton sets the kernel width size
121  */
123  {
124  k_width = 3*(k_order-1)+1;
125  }
126 
127  /**
128  * \brief This funciton returns the order of the kernel
129  */
131  {
132  return k_order;
133  }
134 
135  /**
136  * \brief This funciton returns the number of kernel coefficients
137  */
139  {
140  return k_ncoeffs;
141  }
142 
143  /**
144  * \brief This funciton returns the size of the kernel width
145  */
147  {
148  return k_width;
149  }
150 
151  /**
152  * \brief This funciton moves the center of the kernel to the
153  \param x_value.
154  \param outarray is used to store the result
155  */
156  LIB_UTILITIES_EXPORT void MoveKernelCenter(NekDouble x_value, Array<OneD,NekDouble> &outarray);
157 
158  /**
159  * \brief This funciton calculates the mesh breaks under the kernel support
160  \param inarray contains the local kernel breaks
161  \param h is the mesh spacing
162  \param outarray contains the coordinate of the mesh breaks under the kernel support
163  */
164  LIB_UTILITIES_EXPORT void FindMeshUnderKernel(Array<OneD,NekDouble> &inarray, NekDouble h,
165  Array<OneD,NekDouble> &outarray);
166 
167  /**
168  * \brief This funciton evaluates the kernel at input values
169  \param inarray.
170  \param h is the mesh spacing.
171  \param outarray contains the kernel values
172  */
173  LIB_UTILITIES_EXPORT void EvaluateKernel(Array<OneD,NekDouble> inarray,NekDouble h,
174  Array<OneD,NekDouble> &outarray);
175 
176  /**
177  * \brief This function evaluates the bspline at input values
178  \param inarray input values.
179  \param h the mesh spacing.
180  \param offset
181  \param outarray contains the bspline values.
182  */
183  LIB_UTILITIES_EXPORT void EvaluateBspline(Array<OneD,NekDouble> inarray, NekDouble h,
184  NekDouble offset, Array<OneD,NekDouble> &outarray);
185 
186 
187  /**
188  * \brief This funciton performs the ordered merge of \param inarray1
189  * and \param inarray2 and puts the result in \param outarray
190  */
191  LIB_UTILITIES_EXPORT void Sort(Array<OneD,NekDouble> &inarray1, Array<OneD,NekDouble> &inarray2,
192  Array<OneD,NekDouble> &outarray);
193 
194  protected:
195 
196  int k_order; /**< bsplines are obtained by convolving the characteristic
197  fucntion with itself (k_order - 1) times */
198  int k_ncoeffs; /**< Represents the number of kernel coefficients */
199  int k_width; /**< Represents the width of the kernel */
200  NekDouble k_center; /**< holds the center of the kernel */
201  Array<TwoD,NekDouble> b_spline; /**< 2D array representing the bspline */
202  Array<OneD,NekDouble> k_coeffs; /**< 1D array representing the kernel coefficients */
203  Array<OneD,NekDouble> k_breaks; /**< 1D array representing the kernel breaks */
204 
205  /**
206  * \brief This funciton evaluates the piecewise bspline polynomial
207  \param interval \param interval at point \param x_value.
208  */
209  NekDouble EvaluateBsplinePoly(NekDouble x_value,int interval);
210 
211  private:
212 
213  };
214 
215  typedef boost::shared_ptr<Kernel> KernelSharedPtr;
216 
217  }//end of namespace
218 }// end of namespace
219 
220 #endif //NEKTAR_LIB_UTILIITIES_KERNEL_KERNEL_H