Data update

Task/Brilliant-numbers/FutureBasic/brilliant-numbers-2.basic

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+_top      = 100000000   // 100m is largest magnitude this code can handle
+_max      = 11000       // Number of primes in list
+_prime    = 0
+_notPrime = 1
+uint16    primes(_max)
+uint8     bits(_top / 7)
+ptr       gBase : gBase = @bits( 0 )
+
+
+void local fn init
+print @"\n   A brilliant number is the product of two primes of the same magnitude."
+print @"\n                         First 100 brilliant numbers:"
+
+ptr     p = @primes(0)
+uint64 n1 = 2, n2 = 2
+
+while n1 < _max               // Create list of primes via sieve of Eratosthenes
+if primes(n1) == _prime
+% p, n1                    // add n1 to list of primes
+p += 2
+n2 = n1 << 1
+while n2 < _max
+primes(n2) = _notPrime   // mark all multiples of n1 as not prime
+n2 += n1
+wend
+end if
+n1 ++
+wend
+
+end fn
+
+
+void local fn brilliants
+ptr pn1 = @primes(0), pn2 = pn1
+uint64 mag = 10, n, limit = _top / 3
+
+do
+
+while {pn2} < mag
+n = {pn1} * {pn2}  // mark product of 2 primes as brilliant
+if n >= limit then exit fn
+bits( n >> 3 ) =  bits( n >> 3 ) or bit( n and 7 )
+pn2 += 2
+wend
+
+pn1 += 2 : pn2 = pn1
+if {pn1} > mag then mag *= 10 : if mag == _top then mag = limit
+
+until 0
+stop
+end fn
+
+
+void local fn show
+uint64 count = 0, mag = 1, b, n, v
+ptr    p     = gBase
+
+while count < 100
+v = peek int( p )
+b = 0
+
+while v
+if v and (1 << b)
+v -= (1 << b)
+n = ((p - gBase) << 3) + b
+count++
+print fn StringWithFormat(@"%7d", n);
+if count mod 10 == 0 then print
+
+if n >= mag
+mda_add 2 = count : mda_add = n
+mag *= 10
+end if
+end if
+b++
+wend
+
+p += 4
+wend
+
+//============================
+
+while mag < _top           //search for next magnitude
+
+while p < @bits(mag >> 3) // count up to byte before magnitude
+v = [p]
+
+while v
+count++
+v = v and (v-1)       // clear lowest 1 bit in v
+wend
+
+p += 8                     // move to next 64 bits
+wend
+// least-of-magnitude will be next number found
+
+while peek int( p ) == 0 : p += 4 : wend
+
+//v = peek int( p )
+b = 0
+
+while peek int( p )
+if peek int( p )  and (1 << b)
+count++
+poke int p, peek int( p ) - (1 << b) // Bit has been counted so remove it
+
+// get value of brilliant number
+mda_add   = @(((p - gBase) << 3) + b)  //add it to array
+mda_add 2 = count
+mag      *= 10
+end if
+b++
+wend
+
+p += 4
+wend
+
+//============================
+
+print @"\n                First brilliant number of each magnitude:"
+count = 0
+
+while mda(count)
+printf @"%26d is brilliant number #%d", mda_integer(count), mda_integer 2(count)
+count++
+wend
+
+end fn
+
+
+window 1, @"Brilliant Numbers"
+CFTimeInterval t : t = fn CACurrentMediaTime
+fn init
+fn brilliants
+fn show
+printf @"\n   Time = %.2f milliseconds.", 1000 * (fn CACurrentMediaTime - t)
+
+handleevents