CalmoSoft primes: Difference between revisions

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@@ Line 273: / Line 273: @@
     "fmt"
     "rcu"
-    "strconv"
+    "time"
 )
+var start = time.Now()
-func main() {
-    primes := rcu.Primes(100)
+const max = 50_000_000
-    pc := len(primes)
+var primes = rcu.Primes(max)
+func calmoPrimes(limit int) (int, []int, []int, []int) {
+    var pc, sum int
+    if limit < max {
+        for i := 0; i < len(primes); i++ {
+            if primes[i] > limit {
+                pc = i
+                break
+            }
+        }
+    } else {
+        pc = len(primes)
+    }
+    for i := 0; i < pc; i++ {
+        sum += primes[i]
+    }
     longest := 0
-    var sIndices, eIndices []int
+    var sIndices, eIndices, sums []int
     for i := 0; i < pc; i++ {
+        if pc-i < longest {
+            break
+        }
+        if i > 0 {
+            sum -= primes[i-1]
+        }
+        sum2 := sum
         for j := pc - 1; j >= i; j-- {
             temp := j - i + 1
@@ Line 287: / Line 312: @@
                 break
             }
-            sum := rcu.SumInts(primes[i : j+1])
+            if j < pc-1 {
-            if rcu.IsPrime(sum) {
+                sum2 -= primes[j+1]
+            }
+            if rcu.IsPrime(sum2) {
                 if temp > longest {
                     longest = temp
                     sIndices = []int{i}
                     eIndices = []int{j}
+                    sums = []int{sum2}
                 } else {
                     sIndices = append(sIndices, i)
                     eIndices = append(eIndices, j)
+                    sums = append(sums, sum2)
                 }
                 break
@@ Line 301: / Line 330: @@
         }
     }
+    return longest, sIndices, eIndices, sums
-    fmt.Println("The longest sequence(s) of CalmoSoft primes having a length of", longest, "is/are:\n")
+}
-    for i := 0; i < len(sIndices); i++ {
-        cp := primes[sIndices[i] : eIndices[i]+1]
+func main() {
-        sum := rcu.SumInts(cp)
+    for _, limit := range []int{100, 250, 5000, 10000, 500000, 50000000} {
-        cps := ""
-        for i := 0; i < len(cp); i++ {
+        longest, sIndices, eIndices, sums := calmoPrimes(limit)
+        fmt.Println("For primes up to", rcu.Commatize(limit), "the longest sequence(s) of CalmoSoft primes")
-            cps += strconv.Itoa(cp[i])
+        fmt.Println("having a length of", rcu.Commatize(longest), "is/are:\n")
-            if i < len(cp)-1 {
-                cps += " + "
+        for i := 0; i < len(sIndices); i++ {
+            cp1 := primes[sIndices[i] : sIndices[i]+6]
+            cp2 := primes[eIndices[i]-5 : eIndices[i]+1]
+            cps := ""
+            for _, p := range cp1 {
+                cps += fmt.Sprintf("%d + ", p)
             }
+            cps += ".. + "
+            for _, p := range cp2 {
+                cps += fmt.Sprintf("%d + ", p)
+            }
+            fmt.Printf("%s = %s\n", cps[:len(cps)-3], rcu.Commatize(sums[i]))
         }
+        fmt.Println()
-        cps += " = " + strconv.Itoa(sum) + " which is prime"
-        fmt.Println(cps)
-        if i < len(sIndices)-1 {
-            fmt.Println()
-        }
     }
+    fmt.Printf("Took %d ms\n", time.Since(start).Milliseconds())
 }</syntaxhighlight>
 {{out}}
 <pre>
-The longest sequence(s) of CalmoSoft primes having a length of 21 is/are:
+For primes up to 100 the longest sequence(s) of CalmoSoft primes
+having a length of 21 is/are:
++ 11 + 13 + 17 + 19 + 23 + .. + 67 + 71 + 73 + 79 + 83 + 89 = 953
+For primes up to 250 the longest sequence(s) of CalmoSoft primes
+having a length of 49 is/are:
++ 13 + 17 + 19 + 23 + 29 + .. + 223 + 227 + 229 + 233 + 239 + 241 = 5,813
+For primes up to 5,000 the longest sequence(s) of CalmoSoft primes
+having a length of 665 is/are:
++ 11 + 13 + 17 + 19 + 23 + .. + 4957 + 4967 + 4969 + 4973 + 4987 + 4993 = 1,543,127
+For primes up to 10,000 the longest sequence(s) of CalmoSoft primes
+having a length of 1,223 is/are:
++ 5 + 7 + 11 + 13 + 17 + .. + 9883 + 9887 + 9901 + 9907 + 9923 + 9929 = 5,686,633
++ 11 + 13 + 17 + 19 + 23 + .. + 9901 + 9907 + 9923 + 9929 + 9931 + 9941 = 5,706,497
+For primes up to 500,000 the longest sequence(s) of CalmoSoft primes
+having a length of 41,530 is/are:
++ 3 + 5 + 7 + 11 + 13 + .. + 499787 + 499801 + 499819 + 499853 + 499879 + 499883 = 9,910,236,647
+For primes up to 50,000,000 the longest sequence(s) of CalmoSoft primes
+having a length of 3,001,117 is/are:
++ 11 + 13 + 17 + 19 + 23 + .. + 49999699 + 49999711 + 49999739 + 49999751 + 49999753 + 49999757 = 72,618,848,632,313
+Took 270 ms
-+ 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 = 953 which is prime
 </pre>