adjust enumeration-based generator to make terms that are less

likely to consume all available memory

pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/rbtrees/rbtrees-1.rkt

@@ -290,4 +290,4 @@
       (ins-preserves-rb-tree t)))
 
 (define (generate-enum-term)
-  (generate-term rbtrees t #:i-th (pick-an-index)))
+  (generate-term rbtrees t #:i-th (pick-an-index 0.2)))

pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/rbtrees/rbtrees-2.rkt

@@ -288,4 +288,4 @@
       (ins-preserves-rb-tree t)))
 
 (define (generate-enum-term)
-  (generate-term rbtrees t #:i-th (pick-an-index)))
+  (generate-term rbtrees t #:i-th (pick-an-index 0.2)))

pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/rbtrees/rbtrees-3.rkt

@@ -290,4 +290,4 @@
       (ins-preserves-rb-tree t)))
 
 (define (generate-enum-term)
-  (generate-term rbtrees t #:i-th (pick-an-index)))
+  (generate-term rbtrees t #:i-th (pick-an-index 0.2)))

pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/rbtrees/rbtrees-base.rkt

@@ -290,4 +290,4 @@
       (ins-preserves-rb-tree t)))
 
 (define (generate-enum-term)
-  (generate-term rbtrees t #:i-th (pick-an-index)))
+  (generate-term rbtrees t #:i-th (pick-an-index 0.2)))

pkgs/redex-pkgs/redex-lib/redex/private/generate-term.rkt

@@ -287,10 +287,10 @@
        (values (enum-ith enum (random-natural the-size))
                'ignored))]))
 
-(define (pick-an-index)
-  (max (random-natural/no-mean 0.01)
-       (random-natural/no-mean 0.01)
-       (random-natural/no-mean 0.01)))
+(define (pick-an-index [prob-of-zero 0.01])
+  (max (random-natural/no-mean prob-of-zero)
+       (random-natural/no-mean prob-of-zero)
+       (random-natural/no-mean prob-of-zero)))
 
 ;; (: random-natural/no-mean (-> Real Natural))
 (define (random-natural/no-mean prob-zero)