Fixed small bug in interpolation.

The previous implementation was not using a first position of zero.

src/numeric.rs

@@ -149,6 +149,7 @@ where
  Tx: PartialOrd + ToPrimitive + Copy + Debug,
  Ty: ToPrimitive + NumCast + Copy + Debug,
 {
+ // dbg!((&x, &y, &x0));
  assert!(x.len() == y.len());
  let index = search_sorted(x, x0);
  match index {

src/recmap.rs

@@ -111,7 +111,7 @@ pub struct RateMap {
  pub ends: Vec<Position>,
  /// The n rates in Morgans, between each genomic position.
  pub rates: Vec<RateFloat>,
- /// The n+1 cumulative map lengths at each genomic position.
+ /// The n cumulative map lengths at each genomic position.
  pub map_pos: Vec<RateFloat>,
 }
 
@@ -436,9 +436,17 @@ impl RecMap {
  .get(name)
  .ok_or(RecMapError::NoChrom(name.to_string()))?;
  let ends = &rate_map.ends;
- let interp_result = interp1d(&ends[0..ends.len() - 1], 
- &rate_map.map_pos, 
- position);
+ // dbg!((&ends, &rate_map.map_pos));
+ assert_eq!(ends.len(), rate_map.map_pos.len() + 1);
+
+ // Create a new vector with 0 at the beginning, followed by map_pos
+ let extended_map_pos = std::iter::once(&0.0)
+ .chain(rate_map.map_pos.iter())
+ .cloned()
+ .collect::<Vec<f64>>();
+
+ // NOTE: This has changed recently <!> Still under review.
+ let interp_result = interp1d(&ends, &extended_map_pos, position);
  let interpolated_map_pos =
  interp_result.ok_or(RecMapError::LookupOutOfBounds(name.to_string(), position))?;
  Ok(interpolated_map_pos)
@@ -669,7 +677,7 @@ mod tests {
  &chr1_map.map_pos,
  &to_morgans(vec![0.0, 5.5, 13., 34.65]),
  1e-3,
-  );
+ );
  }
 
  #[test]