improved solution to ch-1 and added solution to ch-2

5 files changed, 136 insertions, 76 deletions

diff --git a/challenge-168/steve-g-lynn/julia/ch-1.jl b/challenge-168/steve-g-lynn/julia/ch-1.jl
new file mode 100755
index 0000000000..e58d43e005
--- /dev/null
+++ b/challenge-168/steve-g-lynn/julia/ch-1.jl
@@ -0,0 +1,29 @@
+#!/usr/bin/julia
+#-- slower than perl or raku for this task because of slow startup
+
+using Primes
+
+function perrin(n::Int64)
+	return ( ([0 1 0; 0 0 1; 1 1 0]^n)*[3;0;2] )[1];
+end
+
+savedprimes=Array{Int64}(undef,13)
+savedprimes[1]=2; savedprimes[2]=3;savedprimes[3]=5;savedprimes[4]=7
+ctr=3;
+
+for n in (6:1000)
+	perrinval=perrin(n)
+	if (isprime(perrinval) && (ctr <=13))
+		savedprimes[ctr]=perrinval
+		global ctr=ctr+1
+	end
+end
+
+print("(")
+for n in (1:13)
+	print(savedprimes[n])
+	print(" ")
+end
+print(")\n")
+
+
diff --git a/challenge-168/steve-g-lynn/perl/ch-1.pl b/challenge-168/steve-g-lynn/perl/ch-1.pl
index a8729418aa..35818da7f9 100755
--- a/challenge-168/steve-g-lynn/perl/ch-1.pl
+++ b/challenge-168/steve-g-lynn/perl/ch-1.pl
@@ -3,8 +3,11 @@
 use Math::Prime::XS qw(is_prime);
 
 local %saveprimes=();
-for (0..150) {
-	local $chk=&perrin($_);
+local @perrin=(3,0,2);
+for (1..150) {
+	local $chk=$perrin[0];
+	push @perrin, $perrin[0]+$perrin[1];
+	shift @perrin;
 	(is_prime($chk)) && ($saveprimes{$chk}=1);
 	@saveprimes==26 && last;
 }
@@ -15,45 +18,4 @@ foreach (sort{$a<=>$b} keys %saveprimes){
 }
 print ")\n";
 
-#-- subs
 
-
-sub perrin {
-	local ($n)=@_;
-	
-	if ($n==0) { return 3 }
-	else { return &postmult_302(&matpow($n)) }
-}
-
-#-- subs for fast computation of perrin number using matrix formula
-#-- see wikipedia https://en.wikipedia.org/wiki/Perrin_number
-
-#-- [0 1 0; 0 0 1; 1 1 0]^n (only need 1st row)
-sub matpow {
-	local ($n)=@_;
-	
-	if ($n==1) { return (0,1,0) }
-	else {return &postmult_010_001_110(&matpow($n-1))}
-}
-
-
-# 3x3 matrix * [0 1 0; 0 0 1; 1 1 0] (retain 1st row of product)
-sub postmult_010_001_110 {
-	# [a11 a12 a13; a21 a22 a23; a31 a32 a33]*[0 1 0; 0 0 1; 1 1 0]
-	local ($a11,$a12,$a13)=@_; #just need 1st row
-	
-	local $b11=$a13;
-	local $b12=$a11+$a13;
-	local $b13=$a12;
-
-	return ($b11,$b12,$b13) #-- return just 1st row
-}
-
-# 3x3 matrix * [3;0;2] retain 1st element of product
-sub postmult_302 {
-	local ($a11,$a12,$a13)=@_; #-- just need 1st row
-	# [a11 a12 a13; a21 a22 a23; a31 a32 a33]*[3;0;2]
-	#
-	return $a11*3+$a13*2; #-- 1st element
-
-}
diff --git a/challenge-168/steve-g-lynn/perl/ch-2.pl b/challenge-168/steve-g-lynn/perl/ch-2.pl
new file mode 100755
index 0000000000..d1f6f0aced
--- /dev/null
+++ b/challenge-168/steve-g-lynn/perl/ch-2.pl
@@ -0,0 +1,37 @@
+#!/usr/bin/perl
+
+use Math::Prime::XS qw(is_prime sieve_primes);
+
+
+print &home_prime(16),"\n";
+#-- should be 31636373 [wikipedia example]
+
+sub home_prime {
+	local ($n)=@_;
+	while (1){
+		$n=&factors($n);
+		(is_prime($n)) && last;
+	}
+	return $n;
+}
+
+
+sub factors {
+	#--return concatenated prime factors of a number n 
+	local ($n)=@_;
+	local @primes=sieve_primes($n);
+	local $retstring="";
+	
+	if (is_prime($n)){
+		return $n;
+	}
+	else {
+		foreach $prime (sort{$a<=>$b} @primes){
+			while ( ($n % $prime) == 0){
+				$n /= $prime;
+				$retstring .= $prime;
+			}
+		}
+	}
+	return $retstring;	
+}
diff --git a/challenge-168/steve-g-lynn/raku/ch-1.p6 b/challenge-168/steve-g-lynn/raku/ch-1.p6
index ace5c647e1..9610889cf2 100755
--- a/challenge-168/steve-g-lynn/raku/ch-1.p6
+++ b/challenge-168/steve-g-lynn/raku/ch-1.p6
@@ -1,8 +1,11 @@
 #!/usr/bin/raku
 
 my %saveprimes=();
+my ($p1,$p2,$p3)=(3,0,2);
 for ^Inf {
-	my $chk=perrin($_);
+	my $chk=$p1;
+	my $p4=$p1+$p2;
+	$p1=$p2; $p2=$p3;$p3=$p4;
 	(is-prime($chk)) && (%saveprimes{$chk}=1);
 	%saveprimes.elems==13 && last;
 }
@@ -10,36 +13,4 @@ for ^Inf {
 say %saveprimes.keys.sort({.Int});
 
 
-#-- subs
 
-multi sub perrin(0) {3} 
-multi sub perrin(Int $n where ($n>0)){postmult_302(matpow($n))}
-
-#-- subs for fast computation of perrin number using matrix formula
-#-- see wikipedia https://en.wikipedia.org/wiki/Perrin_number
-
-#[0 1 0; 0 0 1; 1 1 0]^n (retain 1st row)
-multi sub matpow(1){ (0,1,0) }
-multi sub matpow(Int $n where ($n>1)) { postmult_010_001_110 (matpow($n-1)) }
-
-# 3x3 matrix * [0 1 0; 0 0 1; 1 1 0] (retain 1st row of product)
-sub postmult_010_001_110 (*@inmatrix){
-	# [a11 a12 a13; a21 a22 a23; a31 a32 a33]*[0 1 0; 0 0 1; 1 1 0]
-	my ($a11,$a12,$a13)=@inmatrix; #just need 1st row
-	
-	my $b11=$a13;
-	my $b12=$a11+$a13;
-	my $b13=$a12;
-
-	return ($b11,$b12,$b13) #-- return just 1st row
-}
-
-# 3x3 matrix * [3;0;2] retain 1st element of product
-sub postmult_302 (*@inmatrix){
-	my ($a11,$a12,$a13)=@inmatrix; #-- just need 1st row
-	# [a11 a12 a13; a21 a22 a23; a31 a32 a33]*[3;0;2]
-	#
-	my $b1=$a11*3+$a13*2; #-- 1st element
-	
-	return $b1;
-}
diff --git a/challenge-168/steve-g-lynn/raku/ch-2.p6 b/challenge-168/steve-g-lynn/raku/ch-2.p6
new file mode 100755
index 0000000000..71fa044657
--- /dev/null
+++ b/challenge-168/steve-g-lynn/raku/ch-2.p6
@@ -0,0 +1,61 @@
+#!/usr/bin/raku
+
+say homeprime(16);
+# 31636373
+#-- works but very slow: time real 0m59.301s user 0m58.334s sys 0m0.773s
+#-- on MacBook Air running Linux FC36
+
+#-- sub for home prime
+
+sub homeprime(Int $n){
+	my $ncopy=$n;
+	while (1) {
+		$ncopy=factor($ncopy).Int;
+		($ncopy.is-prime) && last;
+	}
+	return $ncopy;
+}
+
+#--sub for factorizing
+
+multi sub factor (1) {1}
+
+multi sub factor (Int $n where $n > 1){
+#-- returns string concatenation of prime factors
+	my @primes=prime_sieve($n);
+	my $retstring="";
+	my $ncopy=$n;
+
+	($n.is-prime) && (return $n);	
+	
+	for @primes -> $prime {
+		while ( ($ncopy % $prime)==0) {
+			$ncopy /= $prime;
+			$retstring ~= $prime;
+		}
+	}
+	return $retstring;
+}
+
+#--sub for sieve of Eratosthenes
+#-- (algorihm from wikipedia)
+sub prime_sieve(Int $n where $n > 1){
+	my @a = 2..$n;
+	my (%retval=(),@retval=());
+	for (@a) -> $i {
+		%retval{$i}=1;
+	}
+	my @i= 2..round(sqrt($n));
+	for @i -> $i {
+		loop ( my $j=($i*$i); $j <= $n; $j += $i){
+			%retval{$j}=0;			
+		}
+	}
+	my @k = %retval.keys; 
+	for @k -> $k {
+		if (%retval{$k}==1) {
+			push @retval, $k;
+		}
+	}
+	return (@retval.sort:{$^a <=> $^b});	
+}