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/* File assemble_edp.c */
#include "tc.h"
Void
tc_assemble_edp(tc_pvar)
struct tc_str_vars *tc_pvar;
{
#include "tc_void.h"
register Int i;
register Int k;
register Int l;
register Int m;
register Int ii;
register Int start;
register Int wm;
register Int rel;
register Int gen;
/*
* subroutine to assemble the pointers to essentially different positions.
* in the case of a felsch enumeration, note where each generator occurs
* in a unexpanded group defining relator. these positions correspond to
* each essentially different position for each generator for that group
* defining relator. EDP_BEG(generator) points to a list set up in array
* EDP for the essentially different positions for each
* defining relator for that generator. this list consists of the number
* of positions involved for a relator followed by the position in array
* RELATORS where this generator occurs in that relator for each group
* definitions of arrays:
* RELATOR_INDEX---index of relators. RELATOR_INDEX[i] gives the
* beginning position of ith relator in array RELATORS.
* RELATOR_LENGTH---length of relators. RELATOR_LENGTH[i] gives length of ith
* relator (original length).
* EDP_BEG---index of essentially different positions for each generator.
* EDP_BEG[i] gives beginning positions in array edp for generator i.
*/
start = 0;
for (gen = 1; gen <= NDGEN; gen++) {
i = GEN_TO_COL[gen];
ii = GEN_TO_COL[-gen];
/* set the start position of this gen in the array edp. */
EDP_BEG[i] = start;
for (rel = 1; rel <= NDREL; rel++)
/* k points to the beginning and l to the end of base of a relator
* (first of the two). look through each relator for occurrences
* of generator gen or its inverse and note this position in edp.
* RELATOR_EXPONENT[rel] < 0 means this relator is an involutory generator
* relator.
*/
if (RELATOR_EXPONENT[rel] > 0) {
k = RELATOR_INDEX[rel];
l = k - 1 + RELATOR_LENGTH[rel] / RELATOR_EXPONENT[rel];
for (m = k; m <= l; m++) {
wm = RELATORS[m];
if (wm == i || wm == ii) {
EDP[start++] = m;
EDP[start++] = RELATOR_LENGTH[rel];
}
}
}
/* set the end position of this gen in the array EDP. */
EDP_END[i] = start - 2;
}
return;
}
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