| 1 | /* emacs edit mode for this file is -*- C++ -*- */ |
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| 2 | |
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| 3 | |
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| 4 | #include "config.h" |
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| 5 | |
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| 6 | |
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| 7 | #include "cf_assert.h" |
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| 8 | |
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| 9 | #include "cf_defs.h" |
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| 10 | #include "canonicalform.h" |
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| 11 | #include "cf_algorithm.h" |
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| 12 | #include "cf_random.h" |
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| 13 | |
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| 14 | #ifdef HAVE_NTL |
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| 15 | #include "NTLconvert.h" |
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| 16 | #endif |
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| 17 | |
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| 18 | #ifdef HAVE_FLINT |
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| 19 | #include "FLINTconvert.h" |
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| 20 | #endif |
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| 21 | |
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| 22 | static bool |
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| 23 | is_irreducible ( const CanonicalForm & f ) |
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| 24 | { |
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| 25 | CFFList F = factorize( f ); |
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| 26 | return F.length() == 1 && F.getFirst().exp() == 1; |
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| 27 | } |
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| 28 | |
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| 29 | #if defined(HAVE_NTL) || defined(HAVE_FLINT) |
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| 30 | /// computes a random monic irreducible univariate polynomial in x over Fp of |
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| 31 | /// degree i via NTL/FLINT |
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| 32 | CanonicalForm |
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| 33 | randomIrredpoly (int i, const Variable & x) |
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| 34 | { |
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| 35 | int p= getCharacteristic(); |
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| 36 | #ifdef HAVE_FLINT |
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| 37 | nmod_poly_t Irredpoly; |
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| 38 | nmod_poly_init(Irredpoly,p); |
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| 39 | nmod_poly_randtest_monic_irreducible(Irredpoly, FLINTrandom, i+1); |
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| 40 | CanonicalForm CFirredpoly=convertnmod_poly_t2FacCF(Irredpoly,Variable(1)); |
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| 41 | nmod_poly_clear(Irredpoly); |
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| 42 | #elif defined(HAVE_NTL) |
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| 43 | if (fac_NTL_char != p) |
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| 44 | { |
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| 45 | fac_NTL_char= p; |
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| 46 | zz_p::init (p); |
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| 47 | } |
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| 48 | zz_pX NTLirredpoly; |
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| 49 | BuildIrred (NTLirredpoly, i); |
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| 50 | CanonicalForm CFirredpoly= convertNTLzzpX2CF (NTLirredpoly, x); |
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| 51 | #endif |
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| 52 | return CFirredpoly; |
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| 53 | } |
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| 54 | #else |
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| 55 | CanonicalForm |
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| 56 | find_irreducible ( int deg, CFRandom & gen, const Variable & x ) |
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| 57 | { |
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| 58 | CanonicalForm result; |
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| 59 | int i; |
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| 60 | do { |
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| 61 | result = power( x, deg ); |
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| 62 | for ( i = deg-1; i >= 0; i-- ) |
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| 63 | result += gen.generate() * power( x, i ); |
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| 64 | } while ( ! is_irreducible( result ) ); |
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| 65 | return result; |
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| 66 | } |
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| 67 | #endif |
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