Cantera  2.5.1
MultiNewton.h
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1 //! @file MultiNewton.h
2 
3 // This file is part of Cantera. See License.txt in the top-level directory or
4 // at https://cantera.org/license.txt for license and copyright information.
5 
6 #ifndef CT_MULTINEWTON_H
7 #define CT_MULTINEWTON_H
8 
9 #include "MultiJac.h"
10 
11 namespace Cantera
12 {
13 
14 /**
15  * Newton iterator for multi-domain, one-dimensional problems.
16  * Used by class OneDim.
17  * @ingroup onedim
18  */
20 {
21 public:
22  MultiNewton(int sz);
23  virtual ~MultiNewton() {};
24  MultiNewton(const MultiNewton&) = delete;
25  MultiNewton& operator=(const MultiNewton&) = delete;
26 
27  size_t size() {
28  return m_n;
29  }
30 
31  //! Compute the undamped Newton step. The residual function is evaluated
32  //! at `x`, but the Jacobian is not recomputed.
33  void step(doublereal* x, doublereal* step,
34  OneDim& r, MultiJac& jac, int loglevel);
35 
36  /**
37  * Return the factor by which the undamped Newton step 'step0'
38  * must be multiplied in order to keep all solution components in
39  * all domains between their specified lower and upper bounds.
40  */
41  doublereal boundStep(const doublereal* x0, const doublereal* step0,
42  const OneDim& r, int loglevel);
43 
44  /**
45  * On entry, step0 must contain an undamped Newton step for the solution x0.
46  * This method attempts to find a damping coefficient such that the next
47  * undamped step would have a norm smaller than that of step0. If
48  * successful, the new solution after taking the damped step is returned in
49  * x1, and the undamped step at x1 is returned in step1.
50  */
51  int dampStep(const doublereal* x0, const doublereal* step0,
52  doublereal* x1, doublereal* step1, doublereal& s1,
53  OneDim& r, MultiJac& jac, int loglevel, bool writetitle);
54 
55  //! Compute the weighted 2-norm of `step`.
56  doublereal norm2(const doublereal* x, const doublereal* step,
57  OneDim& r) const;
58 
59  /**
60  * Find the solution to F(X) = 0 by damped Newton iteration. On entry, x0
61  * contains an initial estimate of the solution. On successful return, x1
62  * contains the converged solution.
63  */
64  int solve(doublereal* x0, doublereal* x1, OneDim& r, MultiJac& jac,
65  int loglevel);
66 
67  /// Set options.
68  void setOptions(int maxJacAge = 5) {
69  m_maxAge = maxJacAge;
70  }
71 
72  /// Change the problem size.
73  void resize(size_t points);
74 
75 protected:
76  //! Work arrays of size #m_n used in solve().
77  vector_fp m_x, m_stp, m_stp1;
78 
79  int m_maxAge;
80 
81  //! number of variables
82  size_t m_n;
83 
84  doublereal m_elapsed;
85 };
86 }
87 
88 #endif
Class MultiJac evaluates the Jacobian of a system of equations defined by a residual function supplie...
Definition: MultiJac.h:23
Newton iterator for multi-domain, one-dimensional problems.
Definition: MultiNewton.h:20
void resize(size_t points)
Change the problem size.
vector_fp m_x
Work arrays of size m_n used in solve().
Definition: MultiNewton.h:77
doublereal boundStep(const doublereal *x0, const doublereal *step0, const OneDim &r, int loglevel)
Return the factor by which the undamped Newton step 'step0' must be multiplied in order to keep all s...
int dampStep(const doublereal *x0, const doublereal *step0, doublereal *x1, doublereal *step1, doublereal &s1, OneDim &r, MultiJac &jac, int loglevel, bool writetitle)
On entry, step0 must contain an undamped Newton step for the solution x0.
void setOptions(int maxJacAge=5)
Set options.
Definition: MultiNewton.h:68
size_t m_n
number of variables
Definition: MultiNewton.h:82
int solve(doublereal *x0, doublereal *x1, OneDim &r, MultiJac &jac, int loglevel)
Find the solution to F(X) = 0 by damped Newton iteration.
doublereal norm2(const doublereal *x, const doublereal *step, OneDim &r) const
Compute the weighted 2-norm of step.
void step(doublereal *x, doublereal *step, OneDim &r, MultiJac &jac, int loglevel)
Compute the undamped Newton step.
Container class for multiple-domain 1D problems.
Definition: OneDim.h:26
std::vector< double > vector_fp
Turn on the use of stl vectors for the basic array type within cantera Vector of doubles.
Definition: ct_defs.h:180
Namespace for the Cantera kernel.
Definition: AnyMap.cpp:264