knob for lsb vs balance

2 files changed, 35 insertions, 25 deletions

diff --git a/srchr/src/config.rs b/srchr/src/config.rs
index f89aa18..76b9285 100644
--- a/srchr/src/config.rs
+++ b/srchr/src/config.rs
@@ -19,8 +19,8 @@ pub const NUM_PERSIST: usize = 8;
 pub const MAX_NUM_TRANSPOSITIONS: usize = 6;
 
 // Fitness parameters
-pub const STANDARD_DSFB_WEIGHT: f32 = 1.0 / 3.0;
-pub const INDEX_DSFB_WEIGHT: f32 = 1.0 / 3.0;
+pub const STANDARD_DSFB_WEIGHT: f32 = 1.0 / 16.0;
+pub const INDEX_DSFB_WEIGHT: f32 = 1.0 / 16.0;
 
 pub const MIN_INDEX_USAGE_PERCENT: f32 = 0.12;
 pub fn index_usage_fitness(index_perc: f32) -> f32 {
@@ -44,6 +44,9 @@ pub fn pinky_col_penalty(lesser_perc: f32, greater_perc: f32) -> f32 {
     }
 }
 
+// Pre-layout to layout
+pub const MINIMISE_LSB_INSTEAD_OF_OPTIMISING_BALANCE: bool = true;
+
 // -----------------------------------------------------------------------------
 //     Do not change the following, the code makes assumptions about these
 // -----------------------------------------------------------------------------
diff --git a/srchr/src/layout.rs b/srchr/src/layout.rs
index e6ac862..2b8cf05 100644
--- a/srchr/src/layout.rs
+++ b/srchr/src/layout.rs
@@ -167,31 +167,38 @@ impl Layout {
         }
 
         let w_index_columns = weight_function(&pl.index_columns, corpus);
-        // Choose index order to minimise LSB (middle-index only) even though we
-        // don't directly optimise for this parameter
-        let mut lsbs = [0.0; 2];
-        for option in [0, 1] {
-            for left in [true, false] {
-                let mind = if left { 2 } else { 7 };
-                let side = if left { option } else { 1 - option };
-                let m1 = keys[mind + 10 * 0] as u8;
-                let m2 = keys[mind + 10 * 1] as u8;
-                let m3 = keys[mind + 10 * 2] as u8;
-                let i1 = w_index_columns[side].0[3];
-                let i2 = w_index_columns[side].0[4];
-                let i3 = w_index_columns[side].0[5];
-                lsbs[option] += corpus.get_bigram_perc(m1, i1)
-                    + corpus.get_bigram_perc(m1, i2)
-                    + corpus.get_bigram_perc(m1, i3)
-                    + corpus.get_bigram_perc(m2, i1)
-                    + corpus.get_bigram_perc(m2, i2)
-                    + corpus.get_bigram_perc(m2, i3)
-                    + corpus.get_bigram_perc(m3, i1)
-                    + corpus.get_bigram_perc(m3, i2)
-                    + corpus.get_bigram_perc(m3, i3);
+
+        let (left_ind, right_ind);
+        if MINIMISE_LSB_INSTEAD_OF_OPTIMISING_BALANCE {
+            // Choose index order to minimise LSB (middle-index only) even though we
+            // don't directly optimise for this parameter
+            let mut lsbs = [0.0; 2];
+            for option in [0, 1] {
+                for left in [true, false] {
+                    let mind = if left { 2 } else { 7 };
+                    let side = if left { option } else { 1 - option };
+                    let m1 = keys[mind + 10 * 0] as u8;
+                    let m2 = keys[mind + 10 * 1] as u8;
+                    let m3 = keys[mind + 10 * 2] as u8;
+                    let i1 = w_index_columns[side].0[3];
+                    let i2 = w_index_columns[side].0[4];
+                    let i3 = w_index_columns[side].0[5];
+                    lsbs[option] += corpus.get_bigram_perc(m1, i1)
+                        + corpus.get_bigram_perc(m1, i2)
+                        + corpus.get_bigram_perc(m1, i3)
+                        + corpus.get_bigram_perc(m2, i1)
+                        + corpus.get_bigram_perc(m2, i2)
+                        + corpus.get_bigram_perc(m2, i3)
+                        + corpus.get_bigram_perc(m3, i1)
+                        + corpus.get_bigram_perc(m3, i2)
+                        + corpus.get_bigram_perc(m3, i3);
+                }
             }
+            (left_ind, right_ind) = if lsbs[0] < lsbs[1] { (0, 1) } else { (1, 0) }
+        } else {
+            (left_ind, right_ind) = if balance >= 0.0 { (0, 1) } else { (1, 0) }
         }
-        let (left_ind, right_ind) = if lsbs[0] < lsbs[1] { (0, 1) } else { (1, 0) };
+
         for j in 0..3 {
             keys[3 + j * ROW_LENGTH] = w_index_columns[left_ind].0[j] as char;
             keys[6 + j * ROW_LENGTH] = w_index_columns[right_ind].0[j] as char;