Modified permuteExistingNumbers(), moving the isValidSurrealNumber() check into the...

Based on profiling, such a large quantity of invalid numbers was being
generated that data operations were sucking up a significant portion of total
program runtime.

Benchmarking command:
    time ./ch1-breeding-numbers -generations 13 -silent
    go tool pprof ch1-breeding-numbers 13gen-memprofile-gen12.mprof
        top25

Before:
    38.303u 2.233s 0:23.41 173.1%   0+0k 40+62io 354pf+0w
    Showing nodes accounting for 2.29GB, 100% of 2.29GB total

After:
    23.435u 0.887s 0:19.54 124.4%   0+0k 40+52io 347pf+0w
    Showing nodes accounting for 1.12GB, 99.55% of 1.13GB total

diff --git a/chapter-1-experiments/ch1-breeding-numbers.go b/chapter-1-experiments/ch1-breeding-numbers.go
index fc1c397..35f0e20 100644 (file)
--- a/chapter-1-experiments/ch1-breeding-numbers.go
+++ b/chapter-1-experiments/ch1-breeding-numbers.go
@@ -261,13 +261,11 @@ func main() {
         }
         fmt.Printf(" %d", generation)
 
         }
         fmt.Printf(" %d", generation)
 

-        // First generate all possible reduced form symbols per Axiom 1.
-        potentialNumbers := permuteExistingNumbers(generation, universe)
-        // Now prune out any symbols which are NOT valid numbers per Axiom 2.
-        validNumbers := pruneInvalidNumbers(potentialNumbers, universe)
+        // First generate all possible new numbers in this generation.
+        potentiallyNewNumbers := permuteExistingNumbers(generation, universe)

         // Attempt to add the new numbers to the universe. Any duplicates will
         // be weeded out in the attempt.
         // Attempt to add the new numbers to the universe. Any duplicates will
         // be weeded out in the attempt.

-        addNumbersToUniverse(validNumbers, &universe)
+        addNumbersToUniverse(potentiallyNewNumbers, &universe)

 
         // Setup any memory profiling requested by the user. This will snapshot
         // the heap at the end of every generation.
 
         // Setup any memory profiling requested by the user. This will snapshot
         // the heap at the end of every generation.


@@ -313,7 +311,9 @@ func permuteExistingNumbers(generation int, universe surrealUniverse) []surrealN
             leftSet.insert(universe.numbers[i], universe)
             rightSet.insert(universe.numbers[j], universe)
             newSurrealNumber := surrealNumber{leftSet,rightSet,0.0,0,generation}
             leftSet.insert(universe.numbers[i], universe)
             rightSet.insert(universe.numbers[j], universe)
             newSurrealNumber := surrealNumber{leftSet,rightSet,0.0,0,generation}

-            numbers = append(numbers, newSurrealNumber)
+            if isValidSurrealNumber(newSurrealNumber, universe) {
+                numbers = append(numbers, newSurrealNumber)
+            }

         }
     }
     // Now build permutations with one empty set and one 1-element set.
         }
     }
     // Now build permutations with one empty set and one 1-element set.


@@ -329,16 +329,6 @@ func permuteExistingNumbers(generation int, universe surrealUniverse) []surrealN
     return numbers
 }
 
     return numbers
 }
 

-func pruneInvalidNumbers(candidates []surrealNumber, universe surrealUniverse) []surrealNumber {
-    var numbers []surrealNumber
-    for i := 0; i < len(candidates); i++ {
-        if isValidSurrealNumber(candidates[i], universe) {
-            numbers = append(numbers, candidates[i])
-        }
-    }
-    return numbers
-}
-

 // Although a non-reduced-form number is technically valid, for the purposes of
 // this program we're declaring it invalid.
 func isValidSurrealNumber(candidate surrealNumber, universe surrealUniverse) bool {
 // Although a non-reduced-form number is technically valid, for the purposes of
 // this program we're declaring it invalid.
 func isValidSurrealNumber(candidate surrealNumber, universe surrealUniverse) bool {