From 648c7b866a789fdbdad5b1e900bc63c1218edccf Mon Sep 17 00:00:00 2001
From: Lee Spector <lspector@hampshire.edu>
Date: Thu, 7 Dec 2023 11:28:21 -0500
Subject: [PATCH] Implement :gap mutation in :bmx-umad according to
:bmx-gap-change-probability
---
src/propeller/problems/boolean/mul3.cljc | 40 +++++++++++++-----------
src/propeller/variation.cljc | 35 +++++++++++++++------
2 files changed, 48 insertions(+), 27 deletions(-)
diff --git a/src/propeller/problems/boolean/mul3.cljc b/src/propeller/problems/boolean/mul3.cljc
index b1f30df..c46d9f4 100644
--- a/src/propeller/problems/boolean/mul3.cljc
+++ b/src/propeller/problems/boolean/mul3.cljc
@@ -294,22 +294,26 @@
[& args]
(gp/gp
(merge
- {:instructions instructions
- :error-function error-function
- :training-data (:train train-and-test-data)
- :testing-data (:test train-and-test-data)
- :max-generations 1000
- :population-size 1000
- :max-initial-plushy-size 100
- :step-limit 10000
- :parent-selection :lexicase
- :downsample? false
- :ds-function :case-rand
- :downsample-rate 0.1
- :umad-rate 0.01
- :variation {:umad 0
- :bmx 0
- :bmx-umad 1}
- :single-thread-mode false
- :bmx-exchange-rate 0.1}
+ {:instructions instructions
+ :error-function error-function
+ :training-data (:train train-and-test-data)
+ :testing-data (:test train-and-test-data)
+ :max-generations 1000
+ :population-size 1000
+ :max-initial-plushy-size 100
+ :step-limit 10000
+ :parent-selection :lexicase
+ :downsample? false
+ :ds-function :case-rand
+ :downsample-rate 0.1
+ :umad-rate 0.01
+ :variation {:umad 0
+ :bmx 0
+ :bmx-umad 1}
+ :single-thread-mode false
+ :bmx? true
+ :bmx-exchange-rate 0.5
+ :bmx-gap-probability 0.1
+ :bmx-gap-change-probability 0.01
+ :bmx-complementary? true}
(apply hash-map (map #(if (string? %) (read-string %) %) args)))))
diff --git a/src/propeller/variation.cljc b/src/propeller/variation.cljc
index a1f1cd1..a7c804e 100644
--- a/src/propeller/variation.cljc
+++ b/src/propeller/variation.cljc
@@ -130,11 +130,28 @@ The function `new-individual` returns a new individual produced by selection and
[plushy umad-rate]
(if (zero? umad-rate)
plushy
- (remove (fn [item]
- (and (not= item :gap)
- (< (rand)
- (/ 1 (+ 1 (/ 1 umad-rate))))))
- plushy)))
+ (let [adjusted-rate (/ 1 (+ 1 (/ 1 umad-rate)))]
+ (remove (fn [item]
+ (and (not= item :gap)
+ (< (rand) adjusted-rate)))
+ plushy))))
+
+(defn uniform-gap-deletion
+ "Randomly deletes instances of :gap from plushy at some rate, which has to be adjusted not
+ only because additions may already have happened, but also because while :gap can be added
+ anywhere, it can only be deleted where it already is."
+ [plushy gap-change-rate]
+ (let [gap-count (count (filter #(= % :gap) plushy))]
+ (if (or (zero? gap-change-rate)
+ (empty? plushy)
+ (zero? gap-count))
+ plushy
+ (let [adjusted-rate (/ 1 (/ (+ 1 (/ 1 gap-change-rate))
+ (/ (count plushy) gap-count)))]
+ (remove (fn [item]
+ (and (= item :gap)
+ (< (rand) adjusted-rate)))
+ plushy)))))
(defn bmx
"Crosses over two plushies using best match crossover (bmx)."
@@ -185,8 +202,8 @@ The function `new-individual` returns a new individual produced by selection and
(selection/select-parent pop argmap))
plushy1 (:plushy parent1)
plushy2 (:plushy parent2)
- rate (utils/onenum (or (:bmx-exchange-rate argmap) 0.5))]
- (bmx plushy1 plushy2 rate))
+ bmx-exchange-rate (utils/onenum (or (:bmx-exchange-rate argmap) 0.5))]
+ (bmx plushy1 plushy2 bmx-exchange-rate))
;
:umad ;; uniform mutation by addition and deletion, see uniform-deletion for the
;; adjustment that makes this size neutral on average
@@ -209,8 +226,8 @@ The function `new-individual` returns a new individual produced by selection and
plushy2 (:plushy parent2)
bmx-exchange-rate (utils/onenum (or (:bmx-exchange-rate argmap) 0.5))]
(bmx plushy1 plushy2 bmx-exchange-rate))
- (uniform-addition (:instructions argmap) umad-rate)
- (uniform-deletion umad-rate)))
+ (uniform-addition [:gap] (:bmx-gap-change-probability argmap))
+ (uniform-gap-deletion (:bmx-gap-change-probability argmap))))
;
:rumad ;; responsive UMAD, uses a deletion rate computed from the actual
;; number of additions made