/* GSoC12: Tobenna Peter, Igwe (Edited) */
Rat ratreduce (Rat a)
{
if (zero(a.num))
{
/*a.den = 1;*/
itomp(1, a.den);
}
else
{
mp div;
mp c;
if (negative(a.den))
{
/*a.den = -a.den;*/
changesign(a.den);
/*a.num = -a.num;*/
changesign(a.num);
}
/*div = ratgcd(a.den, a.num);*/
ratgcd(a.den, a.num, div);
/*a.num = a.num/div;*/
divint(a.num, div, c);
copy(a.num, c);
/*a.den = a.den/div;*/
divint(a.den, div, c);
copy(a.den, c);
}
return a;
}
void
gcd ( lrs_mp u, lrs_mp v ) /*returns u=gcd(u,v) destroying v */
/*Euclid's algorithm. Knuth, II, p.320
modified to avoid copies r=u,u=v,v=r
Switches to single precision when possible for greater speed */
{
lrs_mp r;
unsigned long ul, vl;
long i;
static unsigned long maxspval = MAXD; /* Max value for the last digit to guarantee */
/* fitting into a single long integer. */
static long maxsplen; /* Maximum digits for a number that will fit */
/* into a single long integer. */
static long firstime = TRUE;
if ( firstime ) { /* initialize constants */
for ( maxsplen = 2; maxspval >= BASE; maxsplen++ )
maxspval /= BASE;
firstime = FALSE;
}
if ( greater ( v, u ) )
goto bigv;
bigu:
if ( zero ( v ) )
return;
if ( ( i = length ( u ) ) < maxsplen || ( i == maxsplen && u[maxsplen - 1] < maxspval ) )
goto quickfinish;
divint ( u, v, r );
normalize ( u );
bigv:
if ( zero ( u ) ) {
copy ( u, v );
return;
}
if ( ( i = length ( v ) ) < maxsplen || ( i == maxsplen && v[maxsplen - 1] < maxspval ) )
goto quickfinish;
divint ( v, u, r );
normalize ( v );
goto bigu;
/* Base 10000 only at the moment */
/* when u and v are small enough, transfer to single precision integers */
/* and finish with euclid's algorithm, then transfer back to lrs_mp */
quickfinish:
ul = vl = 0;
for ( i = length ( u ) - 1; i > 0; i-- )
ul = BASE * ul + u[i];
for ( i = length ( v ) - 1; i > 0; i-- )
vl = BASE * vl + v[i];
if ( ul > vl )
goto qv;
qu:
if ( !vl ) {
for ( i = 1; ul; i++ ) {
u[i] = ul % BASE;
ul = ul / BASE;
}
storelength ( u, i );
return;
}
ul %= vl;
qv:
if ( !ul ) {
for ( i = 1; vl; i++ ) {
u[i] = vl % BASE;
vl = vl / BASE;
}
storelength ( u, i );
return;
}
vl %= ul;
goto qu;
}
