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Strong and weak primes: Difference between revisions

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Strong and weak primes (view source)

Revision as of 01:32, 11 April 2022

5,987 bytes added ,  2 years ago
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→‎{{header|Phix}}: syntax coloured, removed deprecated @=, made better use of builtins, plus some other minor tidying
(Added XPL0 example.)
m (→‎{{header|Phix}}: syntax coloured, removed deprecated @=, made better use of builtins, plus some other minor tidying)
Line 1,799:
 
=={{header|Phix}}==
<!--<lang Phix>(phixonline)-->
Using [[Extensible_prime_generator#Phix]]
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<lang Phix>while sieved<10_000_000 do add_block() end while
<span style="color: #004080;">sequence</span> <span style="color: #000000;">strong</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span> <span style="color: #000000;">weak</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
sequence {strong, weak} @= {}
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">2</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">get_maxprime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e14</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #000080;font-style:italic;">-- (ie idx of primes &lt; (sqrt(1e14)==1e7), bar 1st)</span>
for i=2 to abs(binary_search(10_000_000,primes))-1 do
<span style="color: #004080;">integer</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">),</span>
integer p = primes[i],
<span style="color: #000000;">c</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">compare</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">,(</span><span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)+</span><span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">))/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
c = compare(p,(primes[i-1]+primes[i+1])/2)
<span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=+</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">strong</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">p</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
if c=+1 then strong &= p
<span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=-</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">weak</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">p</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
elsif c=-1 then weak &= p
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
end if
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first thirty six strong primes: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">shorten</span><span style="color: #0000FF;">(</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">36</span><span style="color: #0000FF;">],</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%2d"</span><span style="color: #0000FF;">),</span><span style="color: #008000;">", "</span><span style="color: #0000FF;">)})</span>
end for
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first thirty seven weak primes: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">shorten</span><span style="color: #0000FF;">(</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">37</span><span style="color: #0000FF;">],</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%2d"</span><span style="color: #0000FF;">),</span><span style="color: #008000;">", "</span><span style="color: #0000FF;">)})</span>
printf(1,"The first 36 strong primes:") ?strong[1..36]
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %,d strong primes below %,d and %,d below %,d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">))-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">strong</span><span style="color: #0000FF;">),</span><span style="color: #000000;">1e7</span><span style="color: #0000FF;">})</span>
printf(1,"The first 37 weak primes:") ?weak[1..37]
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %,d weak primes below %,d and %,d below %,d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">))-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span> <span style="color: #000000;">weak</span><span style="color: #0000FF;">),</span><span style="color: #000000;">1e7</span><span style="color: #0000FF;">})</span>
printf(1,"%,7d strong primes below 1,000,000\n",abs(binary_search(1_000_000,strong))-1)
<!--</lang>-->
printf(1,"%,7d strong primes below 10,000,000\n",length(strong))
printf(1,"%,7d weak primes below 1,000,000\n",abs(binary_search(1_000_000,weak))-1)
printf(1,"%,7d weak primes below 10,000,000\n",length(weak))</lang>
{{out}}
<pre>
<pre style="font-size: 11px">
The first 36thirty six strong primes:{ 11, 17, 29, 37,41,59,67,71,79,97,101,107,127,137,149,163,179,191,197,223,227,239,251,269,277,281,307,311,331,347,367,379 ..., 397, 419, 431, 439}
The first 37thirty seven weak primes:{ 3, 7, 13, 19,23,31,43,47,61,73,83,89,103,109,113,131,139,151,167,181,193,199,229,233,241,271,283,293,313,317,337,349,353 ..., 359, 383, 389, 401}
There are 37,723 strong primes below 1,000,000 and 320,991 below 10,000,000
320There are 37,991780 strong weak primes below 1,000,000 and 321,750 below 10,000,000
37,780 weak primes below 1,000,000
321,750 weak primes below 10,000,000
</pre>
 
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