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cfModResultant.cc File Reference

modular resultant algorithm More...

#include "config.h"
#include "cf_assert.h"
#include "timing.h"
#include "cfModResultant.h"
#include "cf_primes.h"
#include "templates/ftmpl_functions.h"
#include "cf_map.h"
#include "cf_algorithm.h"
#include "cf_iter.h"
#include "cf_irred.h"
#include "cf_generator.h"
#include "cf_random.h"
#include "cf_map_ext.h"
#include "facFqBivarUtil.h"
#include "NTLconvert.h"
#include "FLINTconvert.h"

Go to the source code of this file.

Functions

 TIMING_DEFINE_PRINT (fac_resultant_p) static inline void myCompress(const CanonicalForm &F
 
 for (int i=0;i<=n;i++) degsf[i]
 
 if (x.level() !=1)
 
 DELETE_ARRAY (degsg)
 
static CanonicalForm oneNorm (const CanonicalForm &F)
 
static CanonicalForm uniResultant (const CanonicalForm &F, const CanonicalForm &G)
 
static void evalPoint (const CanonicalForm &F, const CanonicalForm &G, CanonicalForm &FEval, CanonicalForm &GEval, CFGenerator &evalPoint)
 
static CanonicalForm newtonInterp (const CanonicalForm &alpha, const CanonicalForm &u, const CanonicalForm &newtonPoly, const CanonicalForm &oldInterPoly, const Variable &x)
 
CanonicalForm resultantFp (const CanonicalForm &A, const CanonicalForm &B, const Variable &x, bool prob)
 modular resultant algorihtm over Fp More...
 
static CanonicalForm balanceUni (const CanonicalForm &f, const CanonicalForm &q)
 
static CanonicalForm symmetricRemainder (const CanonicalForm &f, const CanonicalForm &q)
 
CanonicalForm resultantZ (const CanonicalForm &A, const CanonicalForm &B, const Variable &x, bool prob)
 modular resultant algorihtm over Z More...
 

Variables

const CanonicalFormG
 
const CanonicalForm CFMapM
 
const CanonicalForm CFMap CFMapN
 
const CanonicalForm CFMap CFMap const Variablex
 
int * degsf = NEW_ARRAY(int,n + 1)
 
int * degsg = NEW_ARRAY(int,n + 1)
 
int both_non_zero = 0
 
int f_zero = 0
 
int g_zero = 0
 
int both_zero = 0
 
int degsfx
 
int degsgx
 
int Flevel =F.level()
 
int Glevel =G.level()
 
 else
 

Detailed Description

modular resultant algorithm

Author
Martin Lee

Definition in file cfModResultant.cc.

Function Documentation

◆ balanceUni()

static CanonicalForm balanceUni ( const CanonicalForm f,
const CanonicalForm q 
)
inlinestatic

Definition at line 526 of file cfModResultant.cc.

527{
528 Variable x = f.mvar();
529 CanonicalForm result = 0, qh = q / 2;
532 for ( i = f; i.hasTerms(); i++ ) {
533 c = mod( i.coeff(), q );
534 if ( c > qh )
535 result += power( x, i.exp() ) * (c - q);
536 else
537 result += power( x, i.exp() ) * c;
538 }
539 return result;
540}
CanonicalForm power(const CanonicalForm &f, int n)
exponentiation
CF_NO_INLINE FACTORY_PUBLIC CanonicalForm mod(const CanonicalForm &, const CanonicalForm &)
int i
Definition: cfEzgcd.cc:132
const CanonicalForm CFMap CFMap const Variable & x
FILE * f
Definition: checklibs.c:9
class to iterate through CanonicalForm's
Definition: cf_iter.h:44
factory's main class
Definition: canonicalform.h:86
factory's class for variables
Definition: variable.h:33
return result
Definition: facAbsBiFact.cc:75

◆ DELETE_ARRAY()

DELETE_ARRAY ( degsg  )

◆ evalPoint()

static void evalPoint ( const CanonicalForm F,
const CanonicalForm G,
CanonicalForm FEval,
CanonicalForm GEval,
CFGenerator evalPoint 
)
inlinestatic

Definition at line 310 of file cfModResultant.cc.

313{
314 int degF, degG;
315 Variable x= Variable (1);
316 degF= degree (F, x);
317 degG= degree (G, x);
318 do
319 {
320 if (!evalPoint.hasItems())
321 break;
322 FEval= F (evalPoint.item(), 2);
323 GEval= G (evalPoint.item(), 2);
324 if (degree (FEval, 1) < degF || degree (GEval, 1) < degG)
325 {
326 evalPoint.next();
327 continue;
328 }
329 else
330 return;
331 }
332 while (evalPoint.hasItems());
333}
int degree(const CanonicalForm &f)
static void evalPoint(const CanonicalForm &F, const CanonicalForm &G, CanonicalForm &FEval, CanonicalForm &GEval, CFGenerator &evalPoint)
const CanonicalForm & G

◆ for()

for ( int  i = 0;i<=n;i++)

Definition at line 72 of file cfEzgcd.cc.

73 {
74 if (degsf[i] != 0 && degsg[i] != 0)
75 {
77 continue;
78 }
79 if (degsf[i] == 0 && degsg[i] != 0 && i <= G.level())
80 {
81 f_zero++;
82 continue;
83 }
84 if (degsg[i] == 0 && degsf[i] && i <= F.level())
85 {
86 g_zero++;
87 continue;
88 }
89 }
int * degsf
Definition: cfEzgcd.cc:59
int f_zero
Definition: cfEzgcd.cc:69
const CanonicalForm & G
Definition: cfEzgcd.cc:55
const CanonicalForm CFMap CFMap int & both_non_zero
Definition: cfEzgcd.cc:57
int g_zero
Definition: cfEzgcd.cc:70
int * degsg
Definition: cfEzgcd.cc:60
int level() const
level() returns the level of CO.

◆ if()

if ( x.level() !  = 1)

Definition at line 66 of file cfModResultant.cc.

67 {
68 int xlevel= x.level();
69
70 for (int i= 1; i <= n; i++)
71 {
72 if (degsf[i] != 0 && degsg[i] != 0)
73 {
75 continue;
76 }
77 if (degsf[i] == 0 && degsg[i] != 0 && i <= Glevel)
78 {
79 f_zero++;
80 continue;
81 }
82 if (degsg[i] == 0 && degsf[i] && i <= Flevel)
83 {
84 g_zero++;
85 continue;
86 }
87 }
88
89 M.newpair (Variable (xlevel), Variable (1));
90 N.newpair (Variable (1), Variable (xlevel));
91 degsfx= degsf [xlevel];
92 degsgx= degsg [xlevel];
93 degsf [xlevel]= 0;
94 degsg [xlevel]= 0;
95 if ((getNumVars (F) == 2 && getNumVars (G) == 1) ||
96 (getNumVars (G) == 2 && getNumVars (F) == 1) ||
97 (getNumVars (F) == 2 && getNumVars (F) == getNumVars (G)
98 && getVars (F) == getVars (G)))
99 {
100 int pos= 2;
101 for (int i= 1; i <= n; i++)
102 {
103 if (i != xlevel)
104 {
105 if (i != pos && (degsf[i] != 0 || degsg [i] != 0))
106 {
107 M.newpair (Variable (i), Variable (pos));
108 N.newpair (Variable (pos), Variable (i));
109 pos++;
110 }
111 }
112 }
115 return;
116 }
117
118 if (both_non_zero == 0)
119 {
122 return;
123 }
124
125 // map Variables which do not occur in both polynomials to higher levels
126 int k= 1;
127 int l= 1;
128 for (int i= 1; i <= n; i++)
129 {
130 if (i == xlevel)
131 continue;
132 if (degsf[i] != 0 && degsg[i] == 0 && i <= Flevel)
133 {
134 if (k + both_non_zero != i)
135 {
136 M.newpair (Variable (i), Variable (k + both_non_zero));
137 N.newpair (Variable (k + both_non_zero), Variable (i));
138 }
139 k++;
140 }
141 if (degsf[i] == 0 && degsg[i] != 0 && i <= Glevel)
142 {
143 if (l + g_zero + both_non_zero != i)
144 {
145 M.newpair (Variable (i), Variable (l + g_zero + both_non_zero));
146 N.newpair (Variable (l + g_zero + both_non_zero), Variable (i));
147 }
148 l++;
149 }
150 }
151
152 int m= n;
153 int min_max_deg;
155 l= 0;
156 int i= 1;
157 while (k > 0)
158 {
159 if (degsf [i] != 0 && degsg [i] != 0)
160 min_max_deg= degsgx*degsf[i] + degsfx*degsg[i];
161 else
162 min_max_deg= 0;
163 while (min_max_deg == 0 && i < m)
164 {
165 i++;
166 if (degsf [i] != 0 && degsg [i] != 0)
167 min_max_deg= degsgx*degsf[i] + degsfx*degsg[i];
168 else
169 min_max_deg= 0;
170 }
171 for (int j= i + 1; j <= m; j++)
172 {
173 if (degsgx*degsf[j] + degsfx*degsg[j] <= min_max_deg &&
174 degsf[j] != 0 && degsg [j] != 0)
175 {
176 min_max_deg= degsgx*degsf[j] + degsfx*degsg[j];
177 l= j;
178 }
179 }
180 if (l != 0)
181 {
182 if (l != k && l != xlevel && k != 1)
183 {
184 M.newpair (Variable (l), Variable(k));
185 N.newpair (Variable (k), Variable(l));
186 degsf[l]= 0;
187 degsg[l]= 0;
188 l= 0;
189 }
190 else if (l < m + 1)
191 {
192 degsf[l]= 0;
193 degsg[l]= 0;
194 l= 0;
195 }
196 }
197 else if (l == 0)
198 {
199 if (i != k && i != xlevel && k != 1)
200 {
201 M.newpair (Variable (i), Variable (k));
202 N.newpair (Variable (k), Variable (i));
203 degsf[i]= 0;
204 degsg[i]= 0;
205 }
206 else if (i < m + 1)
207 {
208 degsf[i]= 0;
209 degsg[i]= 0;
210 }
211 i++;
212 }
213 k--;
214 }
215 }
CanonicalForm getVars(const CanonicalForm &f)
CanonicalForm getVars ( const CanonicalForm & f )
Definition: cf_ops.cc:350
int getNumVars(const CanonicalForm &f)
int getNumVars ( const CanonicalForm & f )
Definition: cf_ops.cc:314
int l
Definition: cfEzgcd.cc:100
int m
Definition: cfEzgcd.cc:128
int k
Definition: cfEzgcd.cc:99
int degsgx
const CanonicalForm CFMap CFMap & N
int both_non_zero
int * degsf
int f_zero
int degsfx
int Flevel
int Glevel
const CanonicalForm CFMap & M
int g_zero
int * degsg
#define DELETE_ARRAY(P)
Definition: cf_defs.h:65
int j
Definition: facHensel.cc:110

◆ newtonInterp()

static CanonicalForm newtonInterp ( const CanonicalForm alpha,
const CanonicalForm u,
const CanonicalForm newtonPoly,
const CanonicalForm oldInterPoly,
const Variable x 
)
inlinestatic

Definition at line 336 of file cfModResultant.cc.

339{
340 CanonicalForm interPoly;
341
342 interPoly= oldInterPoly+((u - oldInterPoly (alpha, x))/newtonPoly (alpha, x))
343 *newtonPoly;
344 return interPoly;
345}
Variable alpha
Definition: facAbsBiFact.cc:51

◆ oneNorm()

static CanonicalForm oneNorm ( const CanonicalForm F)
inlinestatic

Definition at line 242 of file cfModResultant.cc.

243{
244 if (F.inZ())
245 return abs (F);
246
248 for (CFIterator i= F; i.hasTerms(); i++)
249 result += oneNorm (i.coeff());
250 return result;
251}
Rational abs(const Rational &a)
Definition: GMPrat.cc:436
static CanonicalForm oneNorm(const CanonicalForm &F)
bool inZ() const
predicates

◆ resultantFp()

CanonicalForm resultantFp ( const CanonicalForm A,
const CanonicalForm B,
const Variable x,
bool  prob = true 
)

modular resultant algorihtm over Fp

Returns
resultantFp returns the resultant of A and B wrt. x
Parameters
[in]Asome poly
[in]Bsome poly
[in]xsome polynomial variable
[in]probif true use probabilistic algorithm

Definition at line 348 of file cfModResultant.cc.

350{
351 ASSERT (getCharacteristic() > 0, "characteristic > 0 expected");
352
353 if (A.isZero() || B.isZero())
354 return 0;
355
356 int degAx= degree (A, x);
357 int degBx= degree (B, x);
358 if (A.level() < x.level())
359 return power (A, degBx);
360 if (B.level() < x.level())
361 return power (B, degAx);
362
363 if (degAx == 0)
364 return power (A, degBx);
365 else if (degBx == 0)
366 return power (B, degAx);
367
368 if (A.isUnivariate() && B.isUnivariate() && A.level() == B.level())
369 return uniResultant (A, B);
370
371 CanonicalForm F= A;
373
374 CFMap M, N;
375 myCompress (F, G, M, N, x);
376
377 F= M (F);
378 G= M (G);
379
380 Variable y= Variable (2);
381
382 CanonicalForm GEval, FEval, recResult, H;
383 CanonicalForm newtonPoly= 1;
384 CanonicalForm modResult= 0;
385
386 Variable z= Variable (1);
387 int bound= degAx*degree (G, 2) + degree (F, 2)*degBx;
388
389 int p= getCharacteristic();
390 CanonicalForm minpoly;
391 Variable alpha= Variable (tmax (F.level(), G.level()) + 1);
392 bool algExt= hasFirstAlgVar (F, alpha) || hasFirstAlgVar (G, alpha);
393 CFGenerator * gen;
394 bool extOfExt= false;
396 CanonicalForm primElemAlpha, imPrimElemAlpha;
397 CFList source,dest;
398 if (!algExt && (p < (1 << 28)))
399 {
400 // pass to an extension of size at least 2^29
401 // for very very large input that is maybe too small though
402 int deg= ceil (29.0*((double) log (2)/log (p)))+1;
403 minpoly= randomIrredpoly (deg, z);
404 alpha= rootOf (minpoly);
405 AlgExtGenerator AlgExtGen (alpha);
406 gen= AlgExtGen.clone();
407 for (int i= 0; i < p; i++) // skip values from the prime field
408 (*gen).next();
409 }
410 else if (!algExt)
411 {
412 FFGenerator FFGen;
413 gen= FFGen.clone();
414 }
415 else
416 {
417 int deg= ceil (29.0*((double) log (2)/log (p)));
418 if (degree (getMipo (alpha)) < deg)
419 {
420 mpz_t field_size;
421 mpz_init (field_size);
422 mpz_ui_pow_ui (field_size, p,
423 deg + degree (getMipo (alpha)) - deg%degree (getMipo (alpha)));
424
425 // field_size needs to fit in an int because of mapUp, mapDown, length of lists etc.
426 if (mpz_fits_sint_p (field_size))
427 {
428 minpoly= randomIrredpoly (deg + degree (getMipo (alpha))
429 - deg%degree (getMipo (alpha)), z);
430 v= rootOf (minpoly);
431 Variable V_buf2;
432 bool primFail= false;
433 extOfExt= true;
434 primElemAlpha= primitiveElement (alpha, V_buf2, primFail);
435 ASSERT (!primFail, "failure in integer factorizer");
436 if (primFail)
437 ; //ERROR
438 else
439 imPrimElemAlpha= mapPrimElem (primElemAlpha, alpha, v);
440 F= mapUp (F, alpha, v, primElemAlpha, imPrimElemAlpha, source, dest);
441 G= mapUp (G, alpha, v, primElemAlpha, imPrimElemAlpha, source, dest);
442 }
443 else
444 {
445 deg= deg - deg % degree (getMipo (alpha));
446 mpz_ui_pow_ui (field_size, p, deg);
447 while (deg / degree (getMipo (alpha)) >= 2 && !mpz_fits_sint_p (field_size))
448 {
449 deg -= degree (getMipo (alpha));
450 mpz_ui_pow_ui (field_size, p, deg);
451 }
452 if (deg != degree (getMipo (alpha)))
453 {
454 minpoly= randomIrredpoly (deg, z);
455 v= rootOf (minpoly);
456 Variable V_buf2;
457 bool primFail= false;
458 extOfExt= true;
459 primElemAlpha= primitiveElement (alpha, V_buf2, primFail);
460 ASSERT (!primFail, "failure in integer factorizer");
461 if (primFail)
462 ; //ERROR
463 else
464 imPrimElemAlpha= mapPrimElem (primElemAlpha, alpha, v);
465 F= mapUp (F, alpha, v, primElemAlpha, imPrimElemAlpha, source, dest);
466 G= mapUp (G, alpha, v, primElemAlpha, imPrimElemAlpha, source, dest);
467 }
468 }
469 mpz_clear (field_size);
470 }
471 AlgExtGenerator AlgExtGen (v);
472 gen= AlgExtGen.clone();
473 for (int i= 0; i < p; i++)
474 (*gen).next();
475 }
476 int count= 0;
477 int equalCount= 0;
478 CanonicalForm point;
479 do
480 {
481 evalPoint (F, G, FEval, GEval, *gen);
482
483 recResult= resultantFp (FEval, GEval, z, prob);
484
485 H= newtonInterp ((*gen).item(), recResult, newtonPoly, modResult, y);
486
487 if (H == modResult)
488 equalCount++;
489 else
490 equalCount= 0;
491
492 count++;
493 if (count > bound || (prob && equalCount == 2 && !H.inCoeffDomain()))
494 {
495 if (!algExt && degree (H, alpha) <= 0)
496 break;
497 else if (algExt)
498 {
499 if (extOfExt && !isInExtension (H, imPrimElemAlpha, 1, primElemAlpha,
500 dest, source))
501 {
502 H= mapDown (H, primElemAlpha, imPrimElemAlpha, alpha, dest, source);
503 prune (v);
504 break;
505 }
506 else if (!extOfExt)
507 break;
508 }
509 }
510
511 modResult= H;
512 newtonPoly *= (y - (*gen).item());
513 if ((*gen).hasItems())
514 (*gen).next();
515 else
516 STICKYASSERT (0, "out of evaluation points");
517 } while (1);
518
519 delete gen;
520
521 return N (H);
522}
bool hasFirstAlgVar(const CanonicalForm &f, Variable &a)
check if poly f contains an algebraic variable a
Definition: cf_ops.cc:679
int FACTORY_PUBLIC getCharacteristic()
Definition: cf_char.cc:70
int myCompress(const CanonicalForm &F, const CanonicalForm &G, CFMap &M, CFMap &N, bool topLevel)
compressing two polynomials F and G, M is used for compressing, N to reverse the compression
Definition: cfModGcd.cc:91
int p
Definition: cfModGcd.cc:4078
CanonicalForm resultantFp(const CanonicalForm &A, const CanonicalForm &B, const Variable &x, bool prob)
modular resultant algorihtm over Fp
static CanonicalForm uniResultant(const CanonicalForm &F, const CanonicalForm &G)
static CanonicalForm newtonInterp(const CanonicalForm &alpha, const CanonicalForm &u, const CanonicalForm &newtonPoly, const CanonicalForm &oldInterPoly, const Variable &x)
#define STICKYASSERT(expression, message)
Definition: cf_assert.h:64
#define ASSERT(expression, message)
Definition: cf_assert.h:99
CanonicalForm randomIrredpoly(int i, const Variable &x)
computes a random monic irreducible univariate polynomial in x over Fp of degree i via NTL/FLINT
Definition: cf_irred.cc:26
static CanonicalForm bound(const CFMatrix &M)
Definition: cf_linsys.cc:460
CanonicalForm mapPrimElem(const CanonicalForm &primElem, const Variable &alpha, const Variable &beta)
compute the image of a primitive element of in . We assume .
Definition: cf_map_ext.cc:450
CanonicalForm primitiveElement(const Variable &alpha, Variable &beta, bool &fail)
determine a primitive element of , is a primitive element of a field which is isomorphic to
Definition: cf_map_ext.cc:342
static CanonicalForm mapDown(const CanonicalForm &F, const Variable &alpha, const CanonicalForm &G, CFList &source, CFList &dest)
the CanonicalForm G is the output of map_up, returns F considered as an element over ,...
Definition: cf_map_ext.cc:123
static CanonicalForm mapUp(const Variable &alpha, const Variable &beta)
and is a primitive element, returns the image of
Definition: cf_map_ext.cc:70
generate all elements in F_p(alpha) starting from 0
Definition: cf_generator.h:94
virtual class for generators
Definition: cf_generator.h:22
virtual CFGenerator * clone() const
Definition: cf_generator.h:30
virtual void next()
Definition: cf_generator.h:29
class CFMap
Definition: cf_map.h:85
CF_NO_INLINE bool isZero() const
bool inCoeffDomain() const
bool isUnivariate() const
generate all elements in F_p starting from 0
Definition: cf_generator.h:56
CFGenerator * clone() const
Definition: cf_generator.cc:52
const CanonicalForm int const CFList const Variable & y
Definition: facAbsFact.cc:53
CanonicalForm H
Definition: facAbsFact.cc:60
b *CanonicalForm B
Definition: facBivar.cc:52
const Variable & v
< [in] a sqrfree bivariate poly
Definition: facBivar.h:39
bool isInExtension(const CanonicalForm &F, const CanonicalForm &gamma, const int k, const CanonicalForm &delta, CFList &source, CFList &dest)
tests if F is not contained in a subfield defined by gamma (Fq case) or k (GF case)
template CanonicalForm tmax(const CanonicalForm &, const CanonicalForm &)
gmp_float log(const gmp_float &a)
Definition: mpr_complex.cc:343
const signed long ceil(const ampf< Precision > &x)
Definition: amp.h:788
int status int void size_t count
Definition: si_signals.h:59
#define A
Definition: sirandom.c:24
void prune(Variable &alpha)
Definition: variable.cc:261
CanonicalForm getMipo(const Variable &alpha, const Variable &x)
Definition: variable.cc:207
Variable rootOf(const CanonicalForm &mipo, char name)
returns a symbolic root of polynomial with name name Use it to define algebraic variables
Definition: variable.cc:162

◆ resultantZ()

CanonicalForm resultantZ ( const CanonicalForm A,
const CanonicalForm B,
const Variable x,
bool  prob = true 
)

modular resultant algorihtm over Z

Returns
resultantZ returns the resultant of A and B wrt. x
Parameters
[in]Asome poly
[in]Bsome poly
[in]xsome polynomial variable
[in]probif true use probabilistic algorithm

Definition at line 559 of file cfModResultant.cc.

561{
562 ASSERT (getCharacteristic() == 0, "characteristic > 0 expected");
563#ifndef NOASSERT
564 bool isRat= isOn (SW_RATIONAL);
565 On (SW_RATIONAL);
566 ASSERT (bCommonDen (A).isOne(), "input A is rational");
567 ASSERT (bCommonDen (B).isOne(), "input B is rational");
568 if (!isRat)
570#endif
571
572 int degAx= degree (A, x);
573 int degBx= degree (B, x);
574 if (A.level() < x.level())
575 return power (A, degBx);
576 if (B.level() < x.level())
577 return power (B, degAx);
578
579 if (degAx == 0)
580 return power (A, degBx);
581 else if (degBx == 0)
582 return power (B, degAx);
583
584 CanonicalForm F= A;
586
587 Variable X= x;
588 if (F.level() != x.level() || G.level() != x.level())
589 {
590 if (F.level() > G.level())
591 X= F.mvar();
592 else
593 X= G.mvar();
594 F= swapvar (F, X, x);
595 G= swapvar (G, X, x);
596 }
597
598 // now X is the main variable
599
600 CanonicalForm d= 0;
601 CanonicalForm dd= 0;
603 for (CFIterator i= F; i.hasTerms(); i++)
604 {
605 buf= oneNorm (i.coeff());
606 d= (buf > d) ? buf : d;
607 }
608 CanonicalForm e= 0, ee= 0;
609 for (CFIterator i= G; i.hasTerms(); i++)
610 {
611 buf= oneNorm (i.coeff());
612 e= (buf > e) ? buf : e;
613 }
614 d= power (d, degBx);
615 e= power (e, degAx);
617 for (int i= degBx + degAx; i > 1; i--)
618 bound *= i;
619 bound *= d*e;
620 bound *= 2;
621
622 bool onRational= isOn (SW_RATIONAL);
623 if (onRational)
625 int i = cf_getNumBigPrimes() - 1;
626 int p;
627 CanonicalForm l= lc (F)*lc(G);
628 CanonicalForm resultModP, q (0), newResult, newQ;
630 int equalCount= 0;
631 CanonicalForm test, newTest;
632 int count= 0;
633 do
634 {
635 p = cf_getBigPrime( i );
636 i--;
637 while ( i >= 0 && mod( l, p ) == 0)
638 {
639 p = cf_getBigPrime( i );
640 i--;
641 }
642
643 if (i <= 0)
644 return resultant (A, B, x);
645
647
648 TIMING_START (fac_resultant_p);
649 resultModP= resultantFp (mapinto (F), mapinto (G), X, prob);
650 TIMING_END_AND_PRINT (fac_resultant_p, "time to compute resultant mod p: ");
651
653
654 count++;
655 if ( q.isZero() )
656 {
657 result= mapinto(resultModP);
658 q= p;
659 }
660 else
661 {
662 chineseRemainder( result, q, mapinto (resultModP), p, newResult, newQ );
663 q= newQ;
664 result= newResult;
666 if (test != newTest)
667 {
668 newTest= test;
669 equalCount= 0;
670 }
671 else
672 equalCount++;
673 if (newQ > bound || (prob && equalCount == 2))
674 {
675 result= test;
676 break;
677 }
678 }
679 } while (1);
680
681 if (onRational)
682 On (SW_RATIONAL);
683 return swapvar (result, X, x);
684}
bool isOn(int sw)
switches
void On(int sw)
switches
void Off(int sw)
switches
CanonicalForm mapinto(const CanonicalForm &f)
CanonicalForm lc(const CanonicalForm &f)
void FACTORY_PUBLIC setCharacteristic(int c)
Definition: cf_char.cc:28
CanonicalForm FACTORY_PUBLIC swapvar(const CanonicalForm &, const Variable &, const Variable &)
swapvar() - swap variables x1 and x2 in f.
Definition: cf_ops.cc:168
CanonicalForm test
Definition: cfModGcd.cc:4096
static CanonicalForm symmetricRemainder(const CanonicalForm &f, const CanonicalForm &q)
CanonicalForm bCommonDen(const CanonicalForm &f)
CanonicalForm bCommonDen ( const CanonicalForm & f )
void FACTORY_PUBLIC chineseRemainder(const CanonicalForm &x1, const CanonicalForm &q1, const CanonicalForm &x2, const CanonicalForm &q2, CanonicalForm &xnew, CanonicalForm &qnew)
void chineseRemainder ( const CanonicalForm & x1, const CanonicalForm & q1, const CanonicalForm & x2,...
Definition: cf_chinese.cc:57
CanonicalForm FACTORY_PUBLIC resultant(const CanonicalForm &f, const CanonicalForm &g, const Variable &x)
CanonicalForm resultant ( const CanonicalForm & f, const CanonicalForm & g, const Variable & x )
static const int SW_RATIONAL
set to 1 for computations over Q
Definition: cf_defs.h:31
int cf_getBigPrime(int i)
Definition: cf_primes.cc:39
int cf_getNumBigPrimes()
Definition: cf_primes.cc:45
Variable mvar() const
mvar() returns the main variable of CO or Variable() if CO is in a base domain.
int status int void * buf
Definition: si_signals.h:59
#define TIMING_START(t)
Definition: timing.h:92
#define TIMING_END_AND_PRINT(t, msg)
Definition: timing.h:94

◆ symmetricRemainder()

static CanonicalForm symmetricRemainder ( const CanonicalForm f,
const CanonicalForm q 
)
inlinestatic

Definition at line 544 of file cfModResultant.cc.

545{
547 if (f.isUnivariate() || f.inCoeffDomain())
548 return balanceUni (f, q);
549 else
550 {
551 Variable x= f.mvar();
552 for (CFIterator i= f; i.hasTerms(); i++)
553 result += power (x, i.exp())*symmetricRemainder (i.coeff(), q);
554 }
555 return result;
556}
static CanonicalForm balanceUni(const CanonicalForm &f, const CanonicalForm &q)

◆ TIMING_DEFINE_PRINT()

TIMING_DEFINE_PRINT ( fac_resultant_p  ) const &

◆ uniResultant()

static CanonicalForm uniResultant ( const CanonicalForm F,
const CanonicalForm G 
)
inlinestatic

Definition at line 255 of file cfModResultant.cc.

256{
257 ASSERT (getCharacteristic() > 0, "characteristic > 0 expected");
258 if (F.inCoeffDomain() && G.inCoeffDomain())
259 return 1;
260 if (F.isZero() || G.isZero())
261 return 0;
263
264#ifdef HAVE_FLINT
265 if (!hasFirstAlgVar (F, alpha) && !hasFirstAlgVar (G,alpha))
266 {
267 nmod_poly_t FLINTF, FLINTG;
268 convertFacCF2nmod_poly_t (FLINTF, F);
269 convertFacCF2nmod_poly_t (FLINTG, G);
270 mp_limb_t FLINTresult= nmod_poly_resultant (FLINTF, FLINTG);
271 nmod_poly_clear (FLINTF);
272 nmod_poly_clear (FLINTG);
273 return CanonicalForm ((long) FLINTresult);
274 }
275 return resultant (F, G, F.mvar());
276#elif defined(HAVE_NTL)
277 if (!hasFirstAlgVar (F, alpha) && !hasFirstAlgVar (G,alpha))
278 {
280 {
282 zz_p::init (getCharacteristic());
283 }
284 zz_pX NTLF= convertFacCF2NTLzzpX (F);
285 zz_pX NTLG= convertFacCF2NTLzzpX (G);
286
287 zz_p NTLResult= resultant (NTLF, NTLG);
288
289 return CanonicalForm (to_long (rep (NTLResult)));
290 }
291 //at this point F or G has an algebraic var.
293 {
295 zz_p::init (getCharacteristic());
296 }
297 zz_pX NTLMipo= convertFacCF2NTLzzpX (getMipo (alpha));
298 zz_pE::init (NTLMipo);
299 zz_pEX NTLF= convertFacCF2NTLzz_pEX (F, NTLMipo);
300 zz_pEX NTLG= convertFacCF2NTLzz_pEX (G, NTLMipo);
301 zz_pE NTLResult= resultant (NTLF, NTLG);
302
303 return convertNTLzzpE2CF (NTLResult, alpha);
304#else
305 return resultant (F, G, F.mvar());
306#endif
307}
zz_pEX convertFacCF2NTLzz_pEX(const CanonicalForm &f, const zz_pX &mipo)
Definition: NTLconvert.cc:1064
CanonicalForm convertNTLzzpE2CF(const zz_pE &coefficient, const Variable &x)
Definition: NTLconvert.cc:799
zz_pX convertFacCF2NTLzzpX(const CanonicalForm &f)
Definition: NTLconvert.cc:105
VAR long fac_NTL_char
Definition: NTLconvert.cc:46
convertFacCF2nmod_poly_t(FLINTmipo, M)
nmod_poly_clear(FLINTmipo)

Variable Documentation

◆ both_non_zero

int both_non_zero = 0

Definition at line 58 of file cfModResultant.cc.

◆ both_zero

int both_zero = 0

Definition at line 61 of file cfModResultant.cc.

◆ degsf

degsf = NEW_ARRAY(int,n + 1)

Definition at line 49 of file cfModResultant.cc.

◆ degsfx

int degsfx

Definition at line 62 of file cfModResultant.cc.

◆ degsg

degsg = NEW_ARRAY(int,n + 1)

Definition at line 50 of file cfModResultant.cc.

◆ degsgx

int degsgx

Definition at line 62 of file cfModResultant.cc.

◆ else

else
Initial value:
{
for (int i= 1; i <= n; i++)
{
if (degsf[i] == 0 && degsg[i] == 0)
{
continue;
}
else
{
if (both_zero != 0 && i != 1)
{
M.newpair (Variable (i), Variable (i - both_zero));
N.newpair (Variable (i - both_zero), Variable (i));
}
}
}
}
int both_zero

Definition at line 216 of file cfModResultant.cc.

◆ f_zero

int f_zero = 0

Definition at line 59 of file cfModResultant.cc.

◆ Flevel

int Flevel =F.level()

Definition at line 63 of file cfModResultant.cc.

◆ G

Definition at line 45 of file cfModResultant.cc.

◆ g_zero

int g_zero = 0

Definition at line 60 of file cfModResultant.cc.

◆ Glevel

int Glevel =G.level()

Definition at line 64 of file cfModResultant.cc.

◆ M

Definition at line 45 of file cfModResultant.cc.

◆ N

Definition at line 46 of file cfModResultant.cc.

◆ x

Initial value:
{
int n= tmax (F.level(), G.level())

Definition at line 46 of file cfModResultant.cc.