int main()
{
int n,x,y,temp;
std::vector<int>elem;
std::scanf("%d",&n);
while( n != 0 )
{
x = y = 0;
for( int i = 0; i < n; i++ )
{
std::scanf("%d",&temp);
elem.push_back(temp);
}
for( size_t i = 0; i < elem.size(); i++ )
for( size_t j = i+1; j< elem.size(); j++ )
{
if(common_factor(elem[i],elem[j])== 1)
x++;
y++;
}
if( x== 0 )
std::printf("No estimate for this data set.\n");
else
std::printf("%0.6lf\n",sqrt(6*y/static_cast<double>(x)));
elem.clear();
std::scanf("%d",&n);
}
return 0;
}
/*==================================================================*/
int
Csrc::gen_src_filter ( int source0, int target )
{
int n;
int ncutoff;
int mem;
int ntaps;
int source;
int source1, target1;
int ncutoff1;
source = source0;
source1 = source;
target1 = source;
ntaps = compute_ntaps ( source, target );
n = target / common_factor ( source, target );
mem = n * ntaps;
if ( source == target )
src.ncase = 0;
else if ( 2 * source == target )
src.ncase = 1;
else if ( source < target )
src.ncase = 2;
else if ( mem <= 780 )
src.ncase = 3;
else
src.ncase = 4;
if ( src.ncase == 4 )
{
source = cascade_factors ( source, target );
if ( source <= 0 )
return 0; // fail
target1 = source;
}
src.ntaps1 = compute_ntaps ( source1, target1 );
src.n1 = target1 / common_factor ( source1, target1 );
src.k1 = source1 / target1;
src.m1 = ( src.n1 * source1 - target1 * src.n1 * src.k1 ) / target1;
src.totcoef1 = src.ntaps1 * src.n1;
ncutoff1 = ( int ) ( 0.90 * src.ntaps1 * target1 / source1 + 0.50 );
if ( ncutoff1 > src.ntaps1 )
ncutoff1 = src.ntaps1;
src.ntaps = compute_ntaps ( source, target );
src.n = target / common_factor ( source, target );
src.k = source / target;
src.m = ( src.n * source - target * src.n * src.k ) / target;
src.totcoef = src.ntaps * src.n;
//ncutoff = 0.85*src.ntaps*target/source + 0.50;
ncutoff = ( int ) ( 0.90 * src.ntaps * target / source + 0.50 );
//ncutoff = (ncutoff & (~1)) | (src.ntaps & 1);
if ( ncutoff > src.ntaps )
ncutoff = src.ntaps;
/*--------------------------------------
//if( (src.n < 50) && (source > target) )
//if( (source > target) )
//if( src.ncase == 4 )
{
printf("\n%5d to %5d", source0, target);
printf(" ncase=%1d", src.ncase);
//if( src.ncase == 4 )
{
printf("\n %5d to %5d", source0, source);
printf(" k+m/n %1d %3d %4d", src.k1, src.m1, src.n1);
printf(" taps = %2d", src.ntaps1);
printf(" ncoefs %5d", src.totcoef1);
printf(" c/o = %2d", ncutoff1);
printf("\n %5d to %5d", source, target);
}
printf(" k+m/n %1d %3d %4d", src.k, src.m, src.n);
printf(" taps = %2d", src.ntaps);
printf(" ncoefs %5d", src.totcoef);
printf(" c/o = %2d", ncutoff);
//printf(" minb %3d", src.minbuf);
}
------------------------------------*/
// init accum filter delta (down counter wrap if <= 0
src.am = src.n;
src.ic = 0; // init
src.minbuf =
( int ) ( 1152.0 * source0 / target + ( src.ntaps - 1 ) + 1 );
if ( src.ncase == 4 )
src.minbuf += ( 128 + 4 );
src.am1 = src.n1;
src.ic1 = 0; // init
src.nbuf = 0;
// return failed if not enough memory
if ( src.totcoef1 > ( sizeof ( src.coef1 ) / sizeof ( float ) ) )
return 0;
if ( src.totcoef > ( sizeof ( src.coef ) / sizeof ( float ) ) )
return 0;
gen_f ( src.coef1, src.ntaps1, ncutoff1, src.n1, src.m1 );
gen_f ( src.coef, src.ntaps, ncutoff, src.n, src.m );
//for(i=0;i<n;i++) outf4(src.coef+i*src.ntaps, src.ntaps);
return src.minbuf;
}
/*==================================================================*/
static int
cascade_factors ( int source, int target )
{
int i;
int cf;
int s, t;
int fs1, ft1;
int fs2, ft2;
int ntaps, ncutoff;
int source2;
int mem;
if ( source <= target )
return source;
cf = common_factor ( source, target );
s = source / cf;
t = target / cf;
ft1 = 0; // init to eliminate compiler warning
fs1 = 0;
for ( i = 7; i < t; i++ )
{
if ( s != i * ( s / i ) )
continue;
if ( t != ( i + 1 ) * ( t / ( i + 1 ) ) )
continue;
fs1 = i;
ft1 = i + 1;
ft2 = t / ft1;
source2 = ft1 * source / fs1;
ntaps = compute_ntaps ( source2, target );
mem = ntaps * ft2;
if ( mem <= 780 )
break;
}
if ( fs1 == 0 )
{
//printf("\n cascade fail");
return 0; // failed
}
//printf("\n fs1 ft1 %3d %3d", fs1, ft1);
fs2 = s / fs1;
ft2 = t / ft1;
//printf(" fs2 ft2 %3d %3d", fs2, ft2);
source2 = ft1 * source / fs1;
ntaps = ( 12 * source2 + target / 2 ) / target;
ncutoff = ( int ) ( 0.85 * ntaps * target / source2 + 0.50 );
//printf("\n stage 2 source %5d", source2);
//printf(" taps = %3d", ntaps);
//printf(" c/o = %3d", ncutoff);
mem = ntaps * ft2;
//printf(" mem = %3d", mem);
return source2;
}