sims2.cpp

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// sims2.cpp
//
// Anton Betten
// January 11, 2009
 
#include "foundations/foundations.h"
#include "group_actions.h"
 
using namespace std;
 
 
namespace orbiter {
namespace layer3_group_actions {
namespace groups {
 
 
 
void choose_random_generator_derived_group(sims *G,
        int *Elt, int verbose_level)
{
    int f_v = (verbose_level >= 1);
    //int f_vv = (verbose_level >= 2);
    int *Elt1, *Elt2, *Elt3, *Elt4, *Elt5, *Elt6;
    actions::action *A;
    
    if (f_v) {
        cout << "choose_random_generator_derived_group" << endl;
        }
    A = G->A;
    Elt1 = NEW_int(A->elt_size_in_int);
    Elt2 = NEW_int(A->elt_size_in_int);
    Elt3 = NEW_int(A->elt_size_in_int);
    Elt4 = NEW_int(A->elt_size_in_int);
    Elt5 = NEW_int(A->elt_size_in_int);
    Elt6 = NEW_int(A->elt_size_in_int);
    
    G->random_element(Elt1, verbose_level - 1);
    G->random_element(Elt2, verbose_level - 1);
    A->invert(Elt1, Elt3);
    A->invert(Elt2, Elt4);
    A->mult(Elt3, Elt4, Elt5);
    A->mult(Elt1, Elt2, Elt6);
    A->mult(Elt5, Elt6, Elt);
    
    FREE_int(Elt1);
    FREE_int(Elt2);
    FREE_int(Elt3);
    FREE_int(Elt4);
    FREE_int(Elt5);
    FREE_int(Elt6);
}
 
void sims::build_up_subgroup_random_process(sims *G, 
    void (*choose_random_generator_for_subgroup)(sims *G,
            int *Elt, int verbose_level),
    int verbose_level)
{
    int f_v = (verbose_level >= 1);
    int f_vv = (verbose_level >= 2);
    int f_vvv = (verbose_level >= 3);
    //int f_vvvv = (verbose_level >= 10);
    ring_theory::longinteger_object go, G_order, quo, rem;
    int drop_out_level, image, cnt, f_added;
    actions::action *GA;
    
    GA = A;
    
    if (f_v) {
        cout << "sims::build_up_subgroup_random_process" << endl;
        }
    G->group_order(G_order);
    group_order(go);
    if (f_v) {
        cout << "sims::build_up_subgroup_random_process(): "
                "old group order is " << G_order << endl;
        cout << "the group is in action " << G->A->label
                << " with base_length = " << G->A->base_len()
            << " and degree " << G->A->degree << endl;
        cout << "the image action has base_length = " << GA->base_len()
            << " and degree " << GA->degree << endl;
        cout << "current action " << GA->label << endl;
        cout << "current group order = " << go << endl;
        }
    cnt = 0;
    while (cnt < 200) {
    
        if (f_vv) {
            cout << "sims::build_up_subgroup_random_process iteration " << cnt << endl;
            }
#if 0
        if (cnt > 1000) {
            cout << "sims::build_up_group_random_process "
                    "cnt > 1000, something seems to be wrong" << endl;
            test_if_subgroup(G, 2);
            exit(1);
            }
#endif
        if (FALSE) {
            G->A->print_base();
            G->print_orbit_len();
            }
        if ((cnt % 2) == 0) {
            if (f_vvv) {
                cout << "sims::build_up_subgroup_random_process choosing random schreier generator" << endl;
                }
            random_schreier_generator(GA->Elt1, 0/*verbose_level - 3*/);
            //A->element_move(schreier_gen, GA->Elt1, 0);
            if (FALSE) {
                cout << "sims::build_up_subgroup_random_process random element chosen:" << endl;
                A->element_print(GA->Elt1, cout);
                cout << endl;
                }
            }
        else if ((cnt % 2) == 1){
            if (f_vvv) {
                cout << "sims::build_up_subgroup_random_process choosing random element in the "
                        "group by which we extend" << endl;
                }
            (*choose_random_generator_for_subgroup)(G,
                    GA->Elt1, verbose_level - 1);
            if (FALSE) {
                cout << "sims::build_up_subgroup_random_process random element chosen" << endl;
                }
            if (FALSE) {
                GA->element_print(GA->Elt1, cout);
                cout << endl;
                }
            }
        if (strip(GA->Elt1, GA->Elt2, drop_out_level,
                image, 0/*verbose_level*/)) {
            if (f_vvv) {
                cout << "sims::build_up_subgroup_random_process element strips through" << endl;
                if (FALSE) {
                    cout << "sims::build_up_subgroup_random_process residue = " << endl;
                    GA->element_print(GA->Elt2, cout);
                    cout << endl;
                    }
                }
            f_added = FALSE;
            closure_group(100, verbose_level - 2);
            }
        else {
            f_added = TRUE;
            if (f_v) {
                cout << "sims::build_up_subgroup_random_process element needs to be inserted at level = "
                    << drop_out_level << " with image "
                    << image << endl;
                if (TRUE) {
                    GA->element_print(GA->Elt2, cout);
                    cout  << endl;
                    }
                }
            add_generator_at_level(GA->Elt2,
                    drop_out_level, 0/*verbose_level - 3*/);
            }
        
        group_order(go);
        if ((f_v && f_added) || f_vv) {
            cout << "sims::build_up_subgroup_random_process new group order is " << go << " : ";
            print_transversal_lengths();
            }
        cnt++;
        }
    if (f_v) {
        cout << "sims::build_up_subgroup_random_process "
                "finished: found a group of order " << go << endl;
        print_transversal_lengths();
        }
}
 
}}}