From 1706306a54cfb5f1bf65f2b054aab2a5a7dba8e7 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 2 Mar 2006 22:11:25 -0800 Subject: [PATCH] diffcore-rename: similarity estimator fix. The "similarity" logic was giving added material way too much negative weight. What we wanted to see was how similar the post-change image was compared to the pre-change image, so the natural definition of similarity is how much common things are there, relative to the post-change image's size. This simplifies things a lot. Signed-off-by: Junio C Hamano --- diffcore-rename.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/diffcore-rename.c b/diffcore-rename.c index 55cf1c37f3..625b589fb7 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -170,19 +170,15 @@ static int estimate_similarity(struct diff_filespec *src, &src_copied, &literal_added)) return 0; - /* Extent of damage */ - if (src->size + literal_added < src_copied) - delta_size = 0; - else - delta_size = (src->size - src_copied) + literal_added; - - /* - * Now we will give some score to it. 100% edit gets 0 points - * and 0% edit gets MAX_SCORE points. + /* How similar are they? + * what percentage of material in dst are from source? */ - score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); - if (score < 0) return 0; - if (MAX_SCORE < score) return MAX_SCORE; + if (dst->size < src_copied) + score = MAX_SCORE; + else if (!dst->size) + score = 0; /* should not happen */ + else + score = src_copied * MAX_SCORE / dst->size; return score; }