feat: add kmer filtering and refactor layer iteration

Introduce a `passes_all` utility to validate kmer rows against multiple filters using short-circuit logic. Integrate a `filters` parameter into the iteration functions to conditionally emit kmers based on filter results. Extract repetitive layer traversal and filtering into an `iter_src_layers` helper, refactoring Pass 1 and Pass 2 to eliminate duplication. Additionally, add a debug conditional to the dump output to include partition and layer metadata alongside kmer sequences.

src/obikindex/src/dump.rs

@@ -36,7 +36,7 @@ impl KmerIndex {
         for i in 0..n {
             if debug {
                 self.partition
-                    .iter_partition_kmers_located(i, use_counts, n_genomes, |part, layer, kmer, row| {
+                    .iter_partition_kmers_located(i, use_counts, n_genomes, &[], |part, layer, kmer, row| {
                         let seq = String::from_utf8(kmer.to_ascii())
                             .unwrap_or_else(|_| "?".repeat(kmer_size));
                         let _ = write!(out, "{part},{layer},{seq}");
@@ -48,7 +48,7 @@ impl KmerIndex {
                     .map_err(OKIError::Partition)?;
             } else {
                 self.partition
-                    .iter_partition_kmers(i, use_counts, n_genomes, |kmer, row| {
+                    .iter_partition_kmers(i, use_counts, n_genomes, &[], |kmer, row| {
                         let seq = String::from_utf8(kmer.to_ascii())
                             .unwrap_or_else(|_| "?".repeat(kmer_size));
                         let _ = write!(out, "{seq}");

src/obikpartitionner/src/dump_layer.rs

@@ -4,6 +4,7 @@ use obiskio::{SKError, SKResult, UnitigFileReader};
 use obilayeredmap::{IndexMode, MphfLayer, OLMError};
 use obilayeredmap::meta::PartitionMeta;
 
+use crate::filter::{KmerFilter, passes_all};
 use crate::partition::KmerPartition;
 
 const INDEX_SUBDIR: &str = "index";
@@ -16,18 +17,21 @@ fn olm_to_sk(e: OLMError) -> SKError {
 }
 
 impl KmerPartition {
-    /// Iterate all indexed kmers in partition `part`, calling `cb(kmer, row)` for each.
+    /// Iterate all indexed kmers in partition `part`, calling `cb(kmer, row)` for each
+    /// kmer that passes every filter in `filters`.
     ///
     /// `use_counts = true`  → reads count columns (u32 values per genome).
     /// `use_counts = false` → reads presence columns, converted to 0/1 u32.
     ///
     /// If no data matrix exists for a layer (pure set-membership, single genome),
-    /// a row of `n_genomes` ones is emitted for every kmer in that layer.
+    /// a row of `n_genomes` ones is emitted for every kmer in that layer — unless
+    /// the filter rejects it, in which case the whole layer is skipped.
     pub fn iter_partition_kmers(
         &self,
         part: usize,
         use_counts: bool,
         n_genomes: usize,
+        filters: &[Box<dyn KmerFilter>],
         mut cb: impl FnMut(CanonicalKmer, Box<[u32]>),
     ) -> SKResult<()> {
         let index_dir = self.part_dir(part).join(INDEX_SUBDIR);
@@ -54,7 +58,10 @@ impl KmerPartition {
                 let mat = PersistentCompactIntMatrix::open(&layer_dir).map_err(SKError::Io)?;
                 for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                     if let Some(slot) = mphf.find(kmer) {
-                        cb(kmer, mat.row(slot));
+                        let row = mat.row(slot);
+                        if passes_all(filters, &row, n_genomes) {
+                            cb(kmer, row);
+                        }
                     }
                 }
             } else if !use_counts && presence_dir.exists() {
@@ -62,12 +69,16 @@ impl KmerPartition {
                 for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                     if let Some(slot) = mphf.find(kmer) {
                         let row: Box<[u32]> = mat.row(slot).iter().map(|&b| b as u32).collect();
+                        if passes_all(filters, &row, n_genomes) {
                             cb(kmer, row);
                         }
                     }
+                }
             } else {
-                // No data matrix: pure set-membership layer, all kmers belong to every genome.
+                // No data matrix: implicit presence — all values are 1.
+                // The filter result is identical for every kmer, so evaluate once.
                 let all_present: Box<[u32]> = vec![1u32; n_genomes].into();
+                if passes_all(filters, &all_present, n_genomes) {
                     for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                         if mphf.find(kmer).is_some() {
                             cb(kmer, all_present.clone());
@@ -75,17 +86,19 @@ impl KmerPartition {
                     }
                 }
             }
+        }
 
         Ok(())
     }
 
-    /// Like [`iter_partition_kmers`] but the callback also receives the layer index,
+    /// Like [`iter_partition_kmers`] but the callback also receives `(partition, layer)`
-    /// enabling debug output that identifies where each kmer was stored.
+    /// indices, enabling debug output that identifies where each kmer was stored.
     pub fn iter_partition_kmers_located(
         &self,
         part: usize,
         use_counts: bool,
         n_genomes: usize,
+        filters: &[Box<dyn KmerFilter>],
         mut cb: impl FnMut(usize, usize, CanonicalKmer, Box<[u32]>),
     ) -> SKResult<()> {
         let index_dir = self.part_dir(part).join(INDEX_SUBDIR);
@@ -111,7 +124,10 @@ impl KmerPartition {
                 let mat = PersistentCompactIntMatrix::open(&layer_dir).map_err(SKError::Io)?;
                 for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                     if let Some(slot) = mphf.find(kmer) {
-                        cb(part, layer, kmer, mat.row(slot));
+                        let row = mat.row(slot);
+                        if passes_all(filters, &row, n_genomes) {
+                            cb(part, layer, kmer, row);
+                        }
                     }
                 }
             } else if !use_counts && presence_dir.exists() {
@@ -119,17 +135,21 @@ impl KmerPartition {
                 for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                     if let Some(slot) = mphf.find(kmer) {
                         let row: Box<[u32]> = mat.row(slot).iter().map(|&b| b as u32).collect();
+                        if passes_all(filters, &row, n_genomes) {
                             cb(part, layer, kmer, row);
                         }
                     }
+                }
             } else {
                 let all_present: Box<[u32]> = vec![1u32; n_genomes].into();
+                if passes_all(filters, &all_present, n_genomes) {
                     for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
                         if mphf.find(kmer).is_some() {
                             cb(part, layer, kmer, all_present.clone());
                         }
                     }
                 }
+            }
             layer += 1;
         }
 

src/obikpartitionner/src/filter.rs

@@ -1,4 +1,4 @@
-/// Trait for kmer row filters used in the rebuild command.
+/// Trait for kmer row filters.
 ///
 /// `row` contains raw per-genome counts (or 0/1 for presence/absence data).
 /// `n_genomes` equals `row.len()`.
@@ -6,6 +6,12 @@ pub trait KmerFilter: Send + Sync {
     fn passes(&self, row: &[u32], n_genomes: usize) -> bool;
 }
 
+/// True when `row` passes every filter in `filters`.
+/// Returns `true` if `filters` is empty.
+pub fn passes_all(filters: &[Box<dyn KmerFilter>], row: &[u32], n_genomes: usize) -> bool {
+    filters.iter().all(|f| f.passes(row, n_genomes))
+}
+
 // ── Quorum filters ─────────────────────────────────────────────────────────────
 
 fn present_count(row: &[u32], threshold: u32) -> usize {

src/obikpartitionner/src/lib.rs

@@ -8,6 +8,6 @@ mod partition;
 mod query_layer;
 mod rebuild_layer;
 
-pub use filter::{GroupQuorumFilter, KmerFilter};
+pub use filter::{GroupQuorumFilter, KmerFilter, passes_all};
 pub use merge_layer::MergeMode;
 pub use partition::{KmerPartition, KmerSpectrum, PARTITIONS_SUBDIR};

src/obikpartitionner/src/rebuild_layer.rs

@@ -7,11 +7,12 @@ use obicompactvec::{PersistentBitMatrixBuilder,
                     PersistentCompactIntMatrixBuilder,
                     PersistentCompactIntVecBuilder};
 use obidebruinj::GraphDeBruijn;
+use obikseq::CanonicalKmer;
 use obiskio::{SKError, SKResult, UnitigFileReader};
 use obilayeredmap::{IndexMode, Layer, MphfLayer, OLMError};
 use obilayeredmap::meta::PartitionMeta;
 
-use crate::filter::KmerFilter;
+use crate::filter::{KmerFilter, passes_all};
 use crate::merge_layer::{MergeMode, SrcLayerData};
 use crate::partition::KmerPartition;
 
@@ -75,8 +76,34 @@ fn load_meta(dir: &Path) -> SKResult<PartitionMeta> {
     }
 }
 
-fn passes_all(filters: &[Box<dyn KmerFilter>], row: &[u32], n_genomes: usize) -> bool {
+/// Iterate all kmers in `src_index_dir` that pass `filters`, yielding `(kmer, row)`.
-    filters.iter().all(|f| f.passes(row, n_genomes))
+///
+/// Uses [`SrcLayerData`] semantics: counts take priority over presence when
+/// `mode = Count`; presence (or implicit all-ones) is used for `Presence`.
+fn iter_src_layers(
+    src_index_dir: &Path,
+    mode: MergeMode,
+    n_genomes: usize,
+    filters: &[Box<dyn KmerFilter>],
+    mut cb: impl FnMut(CanonicalKmer, Box<[u32]>),
+) -> SKResult<()> {
+    let src_meta = load_meta(src_index_dir)?;
+    for l in 0..src_meta.n_layers {
+        let src_layer_dir = src_index_dir.join(format!("layer_{l}"));
+        let unitigs_path  = src_layer_dir.join("unitigs.bin");
+        if !unitigs_path.exists() { continue; }
+
+        let reader   = UnitigFileReader::open_sequential(&unitigs_path)?;
+        let src_data = SrcLayerData::open(&src_layer_dir, mode)?;
+
+        for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
+            let row = src_data.lookup(kmer, n_genomes);
+            if passes_all(filters, &row, n_genomes) {
+                cb(kmer, row.into_boxed_slice());
+            }
+        }
+    }
+    Ok(())
 }
 
 // ── KmerPartition::rebuild_partition ─────────────────────────────────────────
@@ -110,22 +137,9 @@ impl KmerPartition {
 
         // ── Pass 1: collect filtered kmers into de Bruijn graph ───────────────
         let mut g = GraphDeBruijn::new();
-
+        iter_src_layers(&src_index_dir, mode, n_genomes, filters, |kmer, _row| {
-        for l in 0..src_meta.n_layers {
-            let src_layer_dir = src_index_dir.join(format!("layer_{l}"));
-            let unitigs_path = src_layer_dir.join("unitigs.bin");
-            if !unitigs_path.exists() { continue; }
-
-            let reader = UnitigFileReader::open_sequential(&unitigs_path)?;
-            let src_data = SrcLayerData::open(&src_layer_dir, mode)?;
-
-            for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
-                let row = src_data.lookup(kmer, n_genomes);
-                if passes_all(filters, &row, n_genomes) {
             g.push(kmer);
-                }
+        })?;
-            }
-        }
 
         if g.len() == 0 {
             return Ok(());
@@ -176,24 +190,13 @@ impl KmerPartition {
         };
 
         // ── Pass 2: fill builders ─────────────────────────────────────────────
-        for l in 0..src_meta.n_layers {
+        iter_src_layers(&src_index_dir, mode, n_genomes, filters, |kmer, row| {
-            let src_layer_dir = src_index_dir.join(format!("layer_{l}"));
-            let unitigs_path = src_layer_dir.join("unitigs.bin");
-            if !unitigs_path.exists() { continue; }
-
-            let reader = UnitigFileReader::open_sequential(&unitigs_path)?;
-            let src_data = SrcLayerData::open(&src_layer_dir, mode)?;
-
-            for (kmer, _, _) in reader.iter_indexed_canonical_kmers() {
-                let row = src_data.lookup(kmer, n_genomes);
-                if !passes_all(filters, &row, n_genomes) { continue; }
             if let Some(slot) = dst_mphf.find(kmer) {
                 for (col, &value) in row.iter().enumerate() {
                     builders[col].set_val(slot, value);
                 }
             }
-            }
+        })?;
-        }
 
         // ── Close builders, write metadata ────────────────────────────────────
         for b in builders { b.close()?; }