GRASS GIS 8 Programmer's Manual  8.5.0dev(2024)-71f8a81411
n_les.c
Go to the documentation of this file.
1 /*****************************************************************************
2  *
3  * MODULE: Grass PDE Numerical Library
4  * AUTHOR(S): Soeren Gebbert, Berlin (GER) Dec 2006
5  * soerengebbert <at> gmx <dot> de
6  *
7  * PURPOSE: functions to manage linear equation systems
8  * part of the gpde library
9  *
10  * COPYRIGHT: (C) 2000 by the GRASS Development Team
11  *
12  * This program is free software under the GNU General Public
13  * License (>=v2). Read the file COPYING that comes with GRASS
14  * for details.
15  *
16  *****************************************************************************/
17
18 #include <stdlib.h>
19 #include <grass/N_pde.h>
20 #include <grass/gmath.h>
21
22 /*!
23  * \brief Allocate memory for a (not) quadratic linear equation system which
24  * includes the Matrix A, vector x and vector b
25  *
26  * This function calls #N_alloc_les_param
27  *
28  * \param cols int
29  * \param rows int
30  * \param type int
31  * \return N_les *
32  *
33  * */
34 N_les *N_alloc_nquad_les(int cols, int rows, int type)
35 {
36  return N_alloc_les_param(cols, rows, type, 2);
37 }
38
39 /*!
40  * \brief Allocate memory for a (not) quadratic linear equation system which
41  * includes the Matrix A and vector x
42  *
43  * This function calls #N_alloc_les_param
44  *
45  * \param cols int
46  * \param rows int
47  * \param type int
48  * \return N_les *
49  *
50  * */
51 N_les *N_alloc_nquad_les_Ax(int cols, int rows, int type)
52 {
53  return N_alloc_les_param(cols, rows, type, 1);
54 }
55
56 /*!
57  * \brief Allocate memory for a (not) quadratic linear equation system which
58  * includes the Matrix A
59  *
60  * This function calls #N_alloc_les_param
61  *
62  * \param cols int
63  * \param rows int
64  * \param type int
65  * \return N_les *
66  *
67  * */
68 N_les *N_alloc_nquad_les_A(int cols, int rows, int type)
69 {
70  return N_alloc_les_param(cols, rows, type, 0);
71 }
72
73 /*!
74  * \brief Allocate memory for a (not) quadratic linear equation system which
75  * includes the Matrix A, vector x and vector b
76  *
77  * This function calls #N_alloc_les_param
78  *
79  * \param cols int
80  * \param rows int
81  * \param type int
82  * \return N_les *
83  *
84  * */
85 N_les *N_alloc_nquad_les_Ax_b(int cols, int rows, int type)
86 {
87  return N_alloc_les_param(cols, rows, type, 2);
88 }
89
90 /*!
91  * \brief Allocate memory for a quadratic linear equation system which includes
92  * the Matrix A, vector x and vector b
93  *
94  * This function calls #N_alloc_les_param
95  *
96  * \param rows int
97  * \param type int
98  * \return N_les *
99  *
100  * */
101 N_les *N_alloc_les(int rows, int type)
102 {
103  return N_alloc_les_param(rows, rows, type, 2);
104 }
105
106 /*!
107  * \brief Allocate memory for a quadratic linear equation system which includes
108  * the Matrix A and vector x
109  *
110  * This function calls #N_alloc_les_param
111  *
112  * \param rows int
113  * \param type int
114  * \return N_les *
115  *
116  * */
117 N_les *N_alloc_les_Ax(int rows, int type)
118 {
119  return N_alloc_les_param(rows, rows, type, 1);
120 }
121
122 /*!
123  * \brief Allocate memory for a quadratic linear equation system which includes
124  * the Matrix A
125  *
126  * This function calls #N_alloc_les_param
127  *
128  * \param rows int
129  * \param type int
130  * \return N_les *
131  *
132  * */
133 N_les *N_alloc_les_A(int rows, int type)
134 {
135  return N_alloc_les_param(rows, rows, type, 0);
136 }
137
138 /*!
139  * \brief Allocate memory for a quadratic linear equation system which includes
140  * the Matrix A, vector x and vector b
141  *
142  * This function calls #N_alloc_les_param
143  *
144  * \param rows int
145  * \param type int
146  * \return N_les *
147  *
148  * */
149 N_les *N_alloc_les_Ax_b(int rows, int type)
150 {
151  return N_alloc_les_param(rows, rows, type, 2);
152 }
153
154 /*!
155  * \brief Allocate memory for a quadratic or not quadratic linear equation
156  * system
157  *
158  * The type of the linear equation system must be N_NORMAL_LES for
159  * a regular quadratic matrix or N_SPARSE_LES for a sparse matrix
160  *
161  * <p>
162  * In case of N_NORMAL_LES
163  *
164  * A quadratic matrix of size rows*rows*sizeof(double) will allocated
165  *
166  * <p>
167  * In case of N_SPARSE_LES
168  *
169  * a vector of size row will be allocated, ready to hold additional allocated
170  * sparse vectors. each sparse vector may have a different size.
171  *
172  * Parameter parts defines which parts of the les should be allocated.
173  * The number of columns and rows defines if the matrix is quadratic.
174  *
175  * \param cols int
176  * \param rows int
177  * \param type int
178  * \param parts int -- 2 = A, x and b; 1 = A and x; 0 = A allocated
179  * \return N_les *
180  *
181  * */
182 N_les *N_alloc_les_param(int cols, int rows, int type, int parts)
183 {
184  N_les *les;
185
186  int i;
187
188  if (type == N_SPARSE_LES)
189  G_debug(2,
190  "Allocate memory for a sparse linear equation system with %i "
191  "rows\n",
192  rows);
193  else
194  G_debug(2,
195  "Allocate memory for a regular linear equation system with %i "
196  "rows\n",
197  rows);
198
199  les = (N_les *)G_calloc(1, sizeof(N_les));
200
201  if (parts > 0) {
202  les->x = (double *)G_calloc(cols, sizeof(double));
203  for (i = 0; i < cols; i++)
204  les->x[i] = 0.0;
205  }
206
207  if (parts > 1) {
208  les->b = (double *)G_calloc(cols, sizeof(double));
209  for (i = 0; i < cols; i++)
210  les->b[i] = 0.0;
211  }
212
213  les->A = NULL;
214  les->Asp = NULL;
215  les->rows = rows;
216  les->cols = cols;
217  if (rows == cols)
219  else
221
222  if (type == N_SPARSE_LES) {
223  les->Asp = G_math_alloc_spmatrix(rows);
224  les->type = N_SPARSE_LES;
225  }
226  else {
227  les->A = G_alloc_matrix(rows, cols);
228  les->type = N_NORMAL_LES;
229  }
230
231  return les;
232 }
233
234 /*!
235  *
236  * \brief prints the linear equation system to stdout
237  *
238  * <p>
239  * Format:
240  * A*x = b
241  *
242  * <p>
243  * Example
244  \verbatim
245
246  2 1 1 1 * 2 = 0.1
247  1 2 0 0 * 3 = 0.2
248  1 0 2 0 * 3 = 0.2
249  1 0 0 2 * 2 = 0.1
250
251  \endverbatim
252  *
253  * \param les N_les *
254  * \return void
255  *
256  * */
257 void N_print_les(N_les *les)
258 {
259  int i, j, k, out;
260
261  if (les->type == N_SPARSE_LES) {
262  for (i = 0; i < les->rows; i++) {
263  for (j = 0; j < les->cols; j++) {
264  out = 0;
265  for (k = 0; (unsigned int)k < les->Asp[i]->cols; k++) {
266  if (les->Asp[i]->index[k] == (unsigned int)j) {
267  fprintf(stdout, "%4.5f ", les->Asp[i]->values[k]);
268  out = 1;
269  }
270  }
271  if (!out)
272  fprintf(stdout, "%4.5f ", 0.0);
273  }
274  if (les->x)
275  fprintf(stdout, " * %4.5f", les->x[i]);
276  if (les->b)
277  fprintf(stdout, " = %4.5f ", les->b[i]);
278
279  fprintf(stdout, "\n");
280  }
281  }
282  else {
283
284  for (i = 0; i < les->rows; i++) {
285  for (j = 0; j < les->cols; j++) {
286  fprintf(stdout, "%4.5f ", les->A[i][j]);
287  }
288  if (les->x)
289  fprintf(stdout, " * %4.5f", les->x[i]);
290  if (les->b)
291  fprintf(stdout, " = %4.5f ", les->b[i]);
292
293  fprintf(stdout, "\n");
294  }
295  }
296  return;
297 }
298
299 /*!
300  * \brief Release the memory of the linear equation system
301  *
302  * \param les N_les *
303  * \return void
304  *
305  * */
306
307 void N_free_les(N_les *les)
308 {
309  if (les->type == N_SPARSE_LES)
310  G_debug(2, "Releasing memory of a sparse linear equation system\n");
311  else
312  G_debug(2, "Releasing memory of a regular linear equation system\n");
313
314  if (les) {
315
316  if (les->x)
317  G_free(les->x);
318  if (les->b)
319  G_free(les->b);
320
321  if (les->type == N_SPARSE_LES) {
322
323  if (les->Asp) {
324  G_math_free_spmatrix(les->Asp, les->rows);
325  }
326  }
327  else {
328
329  if (les->A) {
330  G_free_matrix(les->A);
331  }
332  }
333
334  free(les);
335  }
336
337  return;
338 }
#define N_NORMAL_LES
Definition: N_pde.h:25
#define N_SPARSE_LES
Definition: N_pde.h:26
#define NULL
Definition: ccmath.h:32
void G_free(void *)
Free allocated memory.
Definition: gis/alloc.c:150
#define G_calloc(m, n)
Definition: defs/gis.h:95
int G_debug(int, const char *,...) __attribute__((format(printf
void G_free_matrix(double **)
Matrix memory deallocation.
Definition: dalloc.c:161
void G_math_free_spmatrix(G_math_spvector **, int)
Release the memory of the sparse matrix.
G_math_spvector ** G_math_alloc_spmatrix(int)
Allocate memory for a sparse matrix.
Definition: sparse_matrix.c:59
double ** G_alloc_matrix(int, int)
Matrix memory allocation.
Definition: dalloc.c:57
void N_print_les(N_les *les)
prints the linear equation system to stdout
Definition: n_les.c:257
N_les * N_alloc_nquad_les(int cols, int rows, int type)
Allocate memory for a (not) quadratic linear equation system which includes the Matrix A,...
Definition: n_les.c:34
N_les * N_alloc_nquad_les_A(int cols, int rows, int type)
Allocate memory for a (not) quadratic linear equation system which includes the Matrix A.
Definition: n_les.c:68
N_les * N_alloc_les_param(int cols, int rows, int type, int parts)
Definition: n_les.c:182
N_les * N_alloc_les_Ax(int rows, int type)
Allocate memory for a quadratic linear equation system which includes the Matrix A and vector x.
Definition: n_les.c:117
N_les * N_alloc_les(int rows, int type)
Allocate memory for a quadratic linear equation system which includes the Matrix A,...
Definition: n_les.c:101
N_les * N_alloc_nquad_les_Ax(int cols, int rows, int type)
Allocate memory for a (not) quadratic linear equation system which includes the Matrix A and vector x...
Definition: n_les.c:51
void N_free_les(N_les *les)
Release the memory of the linear equation system.
Definition: n_les.c:307
N_les * N_alloc_les_Ax_b(int rows, int type)
Allocate memory for a quadratic linear equation system which includes the Matrix A,...
Definition: n_les.c:149
N_les * N_alloc_les_A(int rows, int type)
Allocate memory for a quadratic linear equation system which includes the Matrix A.
Definition: n_les.c:133
N_les * N_alloc_nquad_les_Ax_b(int cols, int rows, int type)
Allocate memory for a (not) quadratic linear equation system which includes the Matrix A,...
Definition: n_les.c:85
void free(void *)
double * values
Definition: gmath.h:55
unsigned int * index
Definition: gmath.h:57
The linear equation system (les) structure.
Definition: N_pde.h:71
int cols
Definition: N_pde.h:77