CalmoSoft primes: Difference between revisions
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Took 210 ms
</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
type TLongInfo = record
RangeStart,RangeStop: integer;
SeqStart,SeqStop: integer;
Count,Sum: integer;
end;
procedure CalmoSoftPrimes(Memo: TMemo);
{Find longest sequence of prime numbers that adds up to a prime}
var Sieve: TPrimeSieve;
var Best,Tmp: TLongInfo;
var I,Cnt: integer;
var S: string;
function GetLongest(N,Limit: integer): TLongInfo;
{Get longest sequence starting at N}
{Find longest sequence of primes whose sum is prime}
var Next,Sum,Cnt: integer;
begin
Result.Count:=1;
Result.SeqStart:=N;
Result.SeqStop:=N;
Result.Sum:=1;
Sum:=N; Next:=N;
Cnt:=1;
while true do
begin
Next:=Sieve.NextPrime(Next);
if Next>Limit then break;
Sum:=Sum+Next;
Inc(Cnt);
if IsPrime(Sum) then
begin
Result.SeqStop:=Next;
Result.Count:=Cnt;
Result.Sum:=Sum;
end;
end;
end;
function LongestRange(Start,Limit: integer): TLongInfo;
{Find longest sequence between Start and Limit}
{Start should be a prime number}
var I: integer;
begin
I:=Start;
Result.SeqStart:=0;
Result.SeqStop:=0;
Result.Count:=0;
while I<=Limit do
begin
Tmp:=GetLongest(I,Limit);
if Tmp.Count>Result.Count then Result:=Tmp;
I:=Sieve.NextPrime(I);
end;
Result.RangeStart:=Start;
Result.RangeStop:=Limit;
end;
procedure ShowSequenceHeader(Best: TLongInfo);
{Show summary of information}
begin
Memo.Lines.Add('Range: '+IntToStr(Best.RangeStart)+' '+IntToStr(Best.RangeStop));
Memo.Lines.Add('Longest Sequence: '+IntToStr(Best.Count));
Memo.Lines.Add('Sum: '+IntToStr(Best.Sum));
end;
procedure ShowSequence(Best: TLongInfo; Start,Limit: integer);
{Extract sequence info from best and display it}
var S: string;
var I,Cnt: integer;
begin
S:=''; Cnt:=0;
{if Start=0 display full range other wise}
{display from start to limit}
if Start=0 then I:=Best.SeqStart
else I:=Start;
while I<=Best.SeqStop do
begin
Inc(Cnt);
S:=S+Format('%5d',[I]);
if (Cnt mod 10)=0 then S:=S+CRLF;
if Cnt>=Limit then break;
I:=Sieve.NextPrime(I);
end;
Memo.Lines.Add(S);
end;
procedure ShowHeaderSequence(Best: TLongInfo);
{Show header and sequence}
begin
ShowSequenceHeader(Best);
ShowSequence(Best,0,high(integer));
end;
begin
Sieve:=TPrimeSieve.Create;
try
{Create enough primes to cover range}
Sieve.Intialize(1000);
{Find longest sequence in range}
Best:=LongestRange(2,100);
ShowHeaderSequence(Best);
finally Sieve.Free; end;
end;
</syntaxhighlight>
{{out}}
<pre>
Range: 2 100
Longest Sequence: 21
Sum: 953
7 11 13 17 19 23 29 31 37 41
43 47 53 59 61 67 71 73 79 83
89
Elapsed Time: 2.277 ms.
</pre>
=={{header|J}}==
Line 1,046 ⟶ 1,181:
Longest Calmo prime seq (length 3001117) of primes less than 50000000 totals 72618848632313
[7, 11, 13, 17, 19, 23, ... 49999699, 49999711, 49999739, 49999751, 49999753, 49999757]
</pre>
=={{header|Nim}}==
{{trans|Wren}}
With some modifications.
<syntaxhighlight lang="Nim">import std/[algorithm, math, strformat, strutils]
func initPrimes(lim: Natural): seq[int] =
## Build list of primes using a sieve of Erathostenes.
var composite = newSeq[bool]((lim + 1) shr 1)
composite[0] = true
for n in countup(3, int(sqrt(lim.toFloat)), 2):
if not composite[n shr 1]:
for k in countup(n * n, lim, 2 * n):
composite[k shr 1] = true
result.add 2
for n in countup(3, lim, 2):
if not composite[n shr 1]:
result.add n
func isPrime(n: Natural): bool =
## Return "true" is "n" is prime.
if n < 2: return false
if (n and 1) == 0: return n == 2
if n mod 3 == 0: return n == 3
var d = 5
var step = 2
while d * d <= n:
if n mod d == 0:
return false
inc d, step
step = 6 - step
return true
const Max = 50_000_000
let primes = initPrimes(Max)
proc calmoPrimes(limit: Positive): (int, seq[int], seq[int], seq[int]) =
## Find the longest sequence of CalmoSoft primes up to "limit".
let phigh = primes.upperBound(limit) - 1
var sum1 = sum(primes.toOpenArray(0, phigh))
var longest = 0
var sIndices, eIndices, sums: seq[int]
for i in 0..phigh:
if phigh - i + 1 < longest:
break
if i > 0:
dec sum1, primes[i - 1]
let isEven = i == 0
var sum2 = sum1
for j in countdown(phigh, i):
let temp = j - i + 1
if temp < longest:
break
if j < phigh:
dec sum2, primes[j + 1]
if ((temp and 1) == 0) != isEven:
continue
if sum2.isPrime:
if temp > longest:
longest = temp
sIndices = @[i]
eIndices = @[j]
sums = @[sum2]
else:
sIndices.add i
eIndices.add j
sums.add sum2
break
result = (longest, sIndices, eIndices, sums)
func plural(lg: int): (string, string) =
## Return the singular or plural form according to value of "lg".
result = if lg == 1: ("", "is") else: ("s", "are")
for limit in [100, 250, 5000, 10000, 500000, 50000000]:
let (longest, sIndices, eIndices, sums) = calmoPrimes(limit)
let (p1, p2) = plural(sums.len)
echo &"For primes up to {insertSep($limit)} the longest sequence{p1} of CalmoSoft primes"
echo &"having a length of {insertSep($longest)} {p2}:\n"
for i in 0..sIndices.high:
let cp = primes[sIndices[i]..eIndices[i]]
echo &"{cp[0..5].join(\" + \")} + ... + {cp[^6..^1].join(\" + \")} = {sums[i]}"
echo()
</syntaxhighlight>
{{out}}
<pre>For primes up to 100 the longest sequence of CalmoSoft primes
having a length of 21 is:
7 + 11 + 13 + 17 + 19 + 23 + ... + 67 + 71 + 73 + 79 + 83 + 89 = 953
For primes up to 250 the longest sequence of CalmoSoft primes
having a length of 49 is:
11 + 13 + 17 + 19 + 23 + 29 + ... + 223 + 227 + 229 + 233 + 239 + 241 = 5813
For primes up to 5_000 the longest sequence of CalmoSoft primes
having a length of 665 is:
7 + 11 + 13 + 17 + 19 + 23 + ... + 4957 + 4967 + 4969 + 4973 + 4987 + 4993 = 1543127
For primes up to 10_000 the longest sequences of CalmoSoft primes
having a length of 1_223 are:
3 + 5 + 7 + 11 + 13 + 17 + ... + 9883 + 9887 + 9901 + 9907 + 9923 + 9929 = 5686633
7 + 11 + 13 + 17 + 19 + 23 + ... + 9901 + 9907 + 9923 + 9929 + 9931 + 9941 = 5706497
For primes up to 500_000 the longest sequence of CalmoSoft primes
having a length of 41_530 is:
2 + 3 + 5 + 7 + 11 + 13 + ... + 499787 + 499801 + 499819 + 499853 + 499879 + 499883 = 9910236647
For primes up to 50_000_000 the longest sequence of CalmoSoft primes
having a length of 3_001_117 is:
7 + 11 + 13 + 17 + 19 + 23 + ... + 49999699 + 49999711 + 49999739 + 49999751 + 49999753 + 49999757 = 72618848632313
</pre>
Line 1,340 ⟶ 1,594:
{{libheader|Wren-fmt}}
This runs in about 3.5 seconds (cf. Julia 1.3 seconds) on my Core i7 machine. However, 2.6 seconds of that is needed to sieve for primes up to 50 million.
<syntaxhighlight lang="
import "./fmt"for Fmt
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