diff options
| -rwxr-xr-x | challenge-146/wlmb/perl/ch-1.pl | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/challenge-146/wlmb/perl/ch-1.pl b/challenge-146/wlmb/perl/ch-1.pl index b65eddcb78..317809535d 100755 --- a/challenge-146/wlmb/perl/ch-1.pl +++ b/challenge-146/wlmb/perl/ch-1.pl @@ -10,7 +10,7 @@ use PDL::NiceSlice; use Try::Tiny; for my $N(@ARGV?@ARGV:10001){ try{ - die "Argument should be positive: $N" unless $N>=1; + die "Argument $N is not positive\n" unless $N>=1; # Estimate size $M of required sieve by solving $M/log($M) approx $N # unless $N is too small my $M=$N<4?6:find_zero(sub {my $x=shift; $N-$x/log($x)}, @@ -20,7 +20,8 @@ for my $N(@ARGV?@ARGV:10001){ $sieve($_*$_:-1:$_).=0 foreach(2..sqrt($M-1)); # multiples of 'it' are not prime my $primes=$sieve->xvals->where($sieve); # first primes die "Short sieve" unless $N<=$primes->nelem; # shouldn't happen - say "$N-th prime is ", $primes(($N-1)); + my $Nth=$N>1?"$N-th":"$N-st"; + say "The $Nth prime is ", $primes(($N-1)); } catch { say $_;} } @@ -31,5 +32,6 @@ sub find_zero { # Find zero of function using Newton's iteration my $y; my $max=10; # guard against non-convergence do{($y, $x)= ($x, $x-$f->($x)/$d->($x))} until approx($y,$x) or --$max<=0; + die "find_zero didn't converge" unless $max>0; return $x; } |