Change the formula of the missing character.
- Bug: 4271049
- Due to the result of the recent user study, a word with a missing character needs to be promoted a bit.
so I changed the formula from:
- freq * 70 * (n - 2) / (n - 1)
to:
- freq * 90 * (10n - 12) / (10n - 2)
Change-Id: Ibff72cbdb0f2d7b91460a06a0fd39a9f5749aa46
diff --git a/native/src/defines.h b/native/src/defines.h
index 9261207..ff195f4 100644
--- a/native/src/defines.h
+++ b/native/src/defines.h
@@ -138,7 +138,8 @@
#define SUGGEST_WORDS_WITH_SPACE_PROXIMITY true
// The following "rate"s are used as a multiplier before dividing by 100, so they are in percent.
-#define WORDS_WITH_MISSING_CHARACTER_DEMOTION_RATE 70
+#define WORDS_WITH_MISSING_CHARACTER_DEMOTION_RATE 90
+#define WORDS_WITH_MISSING_CHARACTER_DEMOTION_START_POS_10X 12
#define WORDS_WITH_MISSING_SPACE_CHARACTER_DEMOTION_RATE 80
#define WORDS_WITH_EXCESSIVE_CHARACTER_DEMOTION_RATE 75
#define WORDS_WITH_EXCESSIVE_CHARACTER_OUT_OF_PROXIMITY_DEMOTION_RATE 75
diff --git a/native/src/unigram_dictionary.cpp b/native/src/unigram_dictionary.cpp
index c188290..2ae2bca 100644
--- a/native/src/unigram_dictionary.cpp
+++ b/native/src/unigram_dictionary.cpp
@@ -518,9 +518,12 @@
// TODO: Demote by edit distance
int finalFreq = freq * matchWeight;
if (skipPos >= 0) {
- if (mInputLength >= 3) {
- multiplyRate(WORDS_WITH_MISSING_CHARACTER_DEMOTION_RATE *
- (mInputLength - 2) / (mInputLength - 1), &finalFreq);
+ if (mInputLength >= 2) {
+ const int demotionRate = WORDS_WITH_MISSING_CHARACTER_DEMOTION_RATE
+ * (10 * mInputLength - WORDS_WITH_MISSING_CHARACTER_DEMOTION_START_POS_10X)
+ / (10 * mInputLength
+ - WORDS_WITH_MISSING_CHARACTER_DEMOTION_START_POS_10X + 10);
+ multiplyRate(demotionRate, &finalFreq);
} else {
finalFreq = 0;
}