source: vis_dev/vis-2.3/src/tbl/tblIdentity.c @ 84

Last change on this file since 84 was 14, checked in by cecile, 13 years ago

vis2.3
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1/**CFile***********************************************************************
2
3  FileName    [tblIdentity.c]
4
5  PackageName [tbl]
6
7  Synopsis    [Functions used to detect special types of table.  Used, for
8               instance, in network sweeping.]
9
10  SeeAlso     [tbl.h]
11
12  Author      [Fabio Somenzi]
13
14  Copyright   [Copyright (c) 2009, Regents of the University of Colorado
15
16  All rights reserved.
17
18  Redistribution and use in source and binary forms, with or without
19  modification, are permitted provided that the following conditions
20  are met:
21
22  Redistributions of source code must retain the above copyright
23  notice, this list of conditions and the following disclaimer.
24
25  Redistributions in binary form must reproduce the above copyright
26  notice, this list of conditions and the following disclaimer in the
27  documentation and/or other materials provided with the distribution.
28
29  Neither the name of the University of Colorado nor the names of its
30  contributors may be used to endorse or promote products derived from
31  this software without specific prior written permission.
32
33  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
34  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
35  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
36  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
37  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
38  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
39  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
40  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
41  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
43  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
44  POSSIBILITY OF SUCH DAMAGE.]
45
46******************************************************************************/
47#include "tblInt.h"
48
49static char rcsid[] UNUSED = "$Id: tblIdentity.c,v 1.1 2009/04/11 07:10:15 fabio Exp $";
50
51/*---------------------------------------------------------------------------*/
52/* Constant declarations                                                     */
53/*---------------------------------------------------------------------------*/
54
55/*---------------------------------------------------------------------------*/
56/* Stucture declarations                                                     */
57/*---------------------------------------------------------------------------*/
58
59
60/*---------------------------------------------------------------------------*/
61/* Type declarations                                                         */
62/*---------------------------------------------------------------------------*/
63
64
65/*---------------------------------------------------------------------------*/
66/* Variable declarations                                                     */
67/*---------------------------------------------------------------------------*/
68
69
70/*---------------------------------------------------------------------------*/
71/* Macro declarations                                                        */
72/*---------------------------------------------------------------------------*/
73
74
75/**AutomaticStart*************************************************************/
76
77/*---------------------------------------------------------------------------*/
78/* Static function prototypes                                                */
79/*---------------------------------------------------------------------------*/
80
81
82/**AutomaticEnd***************************************************************/
83
84/**Function********************************************************************
85
86  Synopsis[Check whether a table describes an identity function.]
87
88  Description [This function checks whether a table describes an
89  identity.  An identity table has exactly one input and one output
90  variable, which takes the same value as the input.]
91
92  SideEffects []
93
94  SeeAlso []
95
96******************************************************************************/
97boolean
98Tbl_TableIsIdentity(
99  Tbl_Table_t *table
100  )
101{
102  Var_Variable_t *invar = NIL(Var_Variable_t), *outvar = NIL(Var_Variable_t);
103  Var_Variable_t *var;
104  int colNum, rowNum;
105  Tbl_Entry_t *inputEntry, *outputEntry, *defaultEntry, *cumulative;
106  boolean result;
107#if 0
108  Mvf_Function_t *outMvf, *inMvf, *identMvf;
109  array_t *mvarValues;
110  array_t *inMvfArray;
111  Tbl_Table_t *ident;
112#endif
113
114  if (Tbl_TableReadNumInputs(table) != 1) return FALSE;
115  if (Tbl_TableReadNumOutputs(table) != 1) return FALSE;
116
117  Tbl_TableForEachInputVar(table,colNum,var) {
118    invar = var;
119  }
120
121  Tbl_TableForEachOutputVar(table,colNum,var) {
122    outvar = var;
123  }
124
125  if (!Var_VariablesTestHaveSameDomain(invar,outvar)) return FALSE;
126
127  /* We test the following condition.  If a table specifies a value
128   * for all inputs and all rows are consistent with the identity,
129   * then the table is an identity.  A normal default declaration is
130   * treated as a row whose input and output parts equal the default
131   * value.  An equality default declaration is treated like a row
132   * with equality output entry and don't care input entry.
133   * Completeness and nondeterminism are implicitly tested by this
134   * criterion.
135   */
136  defaultEntry = Tbl_TableDefaultReadEntry(table, 0);
137  if (defaultEntry == NIL(Tbl_Entry_t)) {
138    cumulative = Tbl_EntryAlloc(Tbl_EntryNormal_c);
139  } else if (Tbl_EntryIsEqual(defaultEntry)) {
140    cumulative = Tbl_EntryAlloc(Tbl_EntryNormal_c);
141    Tbl_EntrySetValue(cumulative, 0, Var_VariableReadNumValues(invar) - 1);
142  } else {
143    if (Tbl_EntryReadNumValues(defaultEntry) != 1) return FALSE;
144    cumulative = Tbl_EntryDup(defaultEntry);
145  }
146  Tbl_TableForEachOutputEntry(table, rowNum, colNum, outputEntry) {
147    Tbl_Entry_t *tmpEntry;
148    assert(colNum == 0);
149    inputEntry = Tbl_TableReadEntry(table, rowNum, 0, 0);
150    assert(!Tbl_EntryIsEqual(inputEntry));
151    if (!Tbl_EntryIsEqual(outputEntry)) {
152      if (Tbl_EntryReadNumValues(outputEntry) != 1 ||
153          !Tbl_EntryTestEqualEntry(outputEntry,inputEntry)) {
154        Tbl_EntryFree(cumulative);
155        return FALSE;
156      }
157    }
158    tmpEntry = Tbl_EntryMerge(cumulative, inputEntry);
159    Tbl_EntryFree(cumulative);
160    cumulative = tmpEntry;
161  }
162  result = Tbl_EntryReadNumValues(cumulative) ==
163    Var_VariableReadNumValues(invar);
164  Tbl_EntryFree(cumulative);
165  return result;
166
167#if 0
168
169  /* Use the MVF sledgehammer.  Only proceed if an mdd manager was
170   * passed as argument.
171   */
172
173  if (mddMgr == NIL(mdd_manager)) return FALSE;
174
175  /* Create MDD variables for the table inputs. */
176  mdd_restart(mddMgr);
177  mvarValues = array_alloc(int, 1);
178  array_insert_last(int, mvarValues, Var_VariableReadNumValues(invar));
179  mdd_create_variables(mddMgr, mvarValues, NIL(array_t), NIL(array_t));
180  array_free(mvarValues);
181
182  /*
183   * Construct an MVF for each table input. The MVF for column i is the MVF
184   * for MDD variable i.
185   */
186  inMvf = Mvf_FunctionCreateFromVariable(mddMgr, 0);
187  inMvfArray = array_alloc(Mvf_Function_t *, 1);
188  array_insert_last(Mvf_Function_t *, inMvfArray, inMvf);
189
190  outMvf = Tbl_TableBuildMvfFromFanins(table, 0, inMvfArray, mddMgr);
191
192  /* Build a reference identity.  This can be sped up quite a bit, but
193     we are practicing using the tbl package. */
194  ident = Tbl_TableAlloc();
195  colNum = Tbl_TableAddColumn(ident,invar,0);
196  assert(colNum == 1);
197  colNum = Tbl_TableAddColumn(ident,outvar,1);
198  assert(colNum == 1);
199  rowNum = Tbl_TableAddRow(ident);
200  assert(rowNum == 0);
201  inputEntry = Tbl_EntryAlloc(Tbl_EntryNormal_c);
202  Tbl_EntrySetValue(inputEntry, 0, Var_VariableReadNumValues(invar)-1);
203  Tbl_TableSetEntry(ident,inputEntry, 0, 0, 0);
204  outputEntry = Tbl_EntryAlloc(Tbl_EntryEqual_c);
205  Tbl_EntrySetEqual(outputEntry, 0);
206  Tbl_TableSetEntry(ident,outputEntry, 0, 0, 1);
207
208  identMvf = Tbl_TableBuildMvfFromFanins(ident, 0, inMvfArray, mddMgr);
209  Mvf_FunctionArrayFree(inMvfArray);
210  Tbl_TableFree(ident);
211  result = Mvf_FunctionTestIsEqualToFunction(outMvf, identMvf);
212  Mvf_FunctionFree(outMvf);
213  Mvf_FunctionFree(identMvf);
214  return result;
215#endif
216
217} /* Tbl_TableIsIdentity */
218
219
220/**Function********************************************************************
221
222  Synopsis[Check whether a table describes an inverter.]
223
224  Description [This function checks whether a table describes an
225  inverter.  An inverter table has exactly one binary input and one
226  binary output variable, which takes the opposite value as the
227  input.]
228
229  SideEffects []
230
231  SeeAlso []
232
233******************************************************************************/
234boolean
235Tbl_TableIsInverter(
236  Tbl_Table_t *table
237  )
238{
239  Var_Variable_t *invar = NIL(Var_Variable_t), *outvar = NIL(Var_Variable_t);
240  Var_Variable_t *var;
241  int colNum, rowNum;
242  Tbl_Entry_t *inputEntry, *outputEntry, *defaultEntry, *cumulative;
243  boolean result;
244
245  if (Tbl_TableReadNumInputs(table) != 1) return FALSE;
246  if (Tbl_TableReadNumOutputs(table) != 1) return FALSE;
247
248  Tbl_TableForEachInputVar(table,colNum,var) {
249    invar = var;
250  }
251  if (Var_VariableReadNumValues(invar) != 2 ||
252      Var_VariableTestIsSymbolic(invar)) return FALSE;
253
254  Tbl_TableForEachOutputVar(table,colNum,var) {
255    outvar = var;
256  }
257  if (Var_VariableReadNumValues(outvar) != 2 ||
258      Var_VariableTestIsSymbolic(outvar)) return FALSE;
259
260  defaultEntry = Tbl_TableDefaultReadEntry(table, 0);
261  if (defaultEntry == NIL(Tbl_Entry_t)) {
262    cumulative = Tbl_EntryAlloc(Tbl_EntryNormal_c);
263  } else if (Tbl_EntryIsEqual(defaultEntry)) {
264    return FALSE;
265  } else {
266    if (Tbl_EntryReadNumValues(defaultEntry) != 1)
267      return FALSE;
268    cumulative = Tbl_EntryDup(defaultEntry);
269    Tbl_EntryComplement(cumulative, 0, 1);
270  }
271  Tbl_TableForEachOutputEntry(table, rowNum, colNum, outputEntry) {
272    Tbl_Entry_t *tmpEntry;
273    assert(colNum == 0);
274    if (Tbl_EntryIsEqual(outputEntry)) {
275      Tbl_EntryFree(cumulative);
276      return FALSE;
277    }
278
279    inputEntry = Tbl_TableReadEntry(table, rowNum, 0, 0);
280    assert(!Tbl_EntryIsEqual(inputEntry));
281    if (Tbl_EntryReadNumValues(outputEntry) != 1 ||
282        Tbl_EntryTestIntersectEntry(outputEntry,inputEntry)) {
283      Tbl_EntryFree(cumulative);
284      return FALSE;
285    }
286    tmpEntry = Tbl_EntryMerge(cumulative, inputEntry);
287    Tbl_EntryFree(cumulative);
288    cumulative = tmpEntry;
289  }
290  result = Tbl_EntryReadNumValues(cumulative) == 2;
291  Tbl_EntryFree(cumulative);
292  return result;
293
294} /* Tbl_TableIsInverter */
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