Add first 3 value nogood handling

Tests for conclusions drawn upon an no-good has been done

lib/src/nogoods.rs

@@ -2,4 +2,61 @@
 
 pub mod threevalued;
 pub mod twovalued;
+use std::fmt::Display;
+
 pub use twovalued::*;
+
+// pub trait NoGood: std::fmt::Debug + Eq {
+//     /// Returns the number of set (i.e. active) variables.
+//     fn len(&self) -> usize;
+// }
+
+// #[derive(Debug)]
+// pub struct NoGoodStore<N>
+// where
+//     N: NoGood + Clone,
+// {
+//     store: Vec<Vec<N>>,
+// }
+
+// impl<T> NoGoodStore<T>
+// where
+//     T: NoGood + Clone,
+// {
+//     /// Creates a new [NoGoodStore] and assumes a size compatible with the underlying [NoGood] implementations.
+//     pub fn new(size: u32) -> Self {
+//         Self {
+//             store: vec![Vec::new(); size as usize],
+//         }
+//     }
+
+//     /// Tries to create a new [NoGoodStore].
+//     /// Does not succeed if the size is too big for the underlying [NoGood] implementations.
+//     pub fn try_new(size: usize) -> Option<Self> {
+//         Some(Self::new(size.try_into().ok()?))
+//     }
+
+//     pub fn add_ng(&mut self, nogood: T) {
+//         let mut idx = nogood.len();
+//         if idx > 0 {
+//             idx -= 1;
+//             if !self.store[idx].contains(&nogood) {
+//                 self.store[idx].push(nogood);
+//             }
+//         }
+//     }
+// }
+
+// impl<T> Display for NoGoodStore<T>
+// where
+//     T: NoGood + Clone,
+// {
+//     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+//         writeln!(f, "NoGoodStats: [")?;
+//         for (arity, vec) in self.store.iter().enumerate() {
+//             writeln!(f, "{arity}: {}", vec.len())?;
+//             log::debug!("Nogoods:\n {:?}", vec);
+//         }
+//         write!(f, "]")
+//     }
+// }

lib/src/nogoods/threevalued.rs

@@ -1,7 +1,5 @@
 //! Three-valued NoGoods
 
-use std::borrow::Borrow;
-
 use roaring::RoaringBitmap;
 
 use crate::datatypes::Term;
@@ -25,22 +23,154 @@ impl Interpretation {
         self.0 = self.0.invert();
         self
     }
+
+    fn active(&self) -> RoaringBitmap {
+        self.0.active()
+    }
+
+    fn hint(&self) -> RoaringBitmap {
+        ((&self.0.can_be_true & &self.0.can_be_false)
+            | (&self.0.can_be_true & &self.0.can_be_und)
+            | (&self.0.can_be_false & &self.0.can_be_und))
+            & &self.active()
+    }
+
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    fn idx_as_triple(&self, idx: u32) -> (bool, bool, bool) {
+        self.0.idx_as_triple(idx)
+    }
+
+    pub fn conclude(mut self, ng: &NoGood) -> Conclusion {
+        log::debug!("conclude: {:?} with NoGood {:?}", self, ng);
+        if self.len() + 1 < ng.len() { // not matching
+        }
+        let interpretation_cred_active = self.active();
+        let interpretation_active = &interpretation_cred_active & (self.hint() ^ self.0.full());
+        let nogood_active = ng.active();
+
+        let implication = (&interpretation_active ^ &nogood_active) & &nogood_active;
+        let scep_match = self.sceptical_matches(ng);
+
+        match implication.len() {
+            // learning might be possible
+            1 => {
+                if (scep_match & interpretation_active).len() == nogood_active.len() - 1 {
+                    let idx: u32 = implication
+                        .min()
+                        .expect("Checked that implication has a minimal value to be found.");
+                    let (ng_t, ng_f, ng_u) = ng.idx_as_triple(idx);
+                    let mut changes: u8 = 0;
+                    if ng_t && self.0.can_be_true.remove(idx) {
+                        changes += 1;
+                    }
+                    if ng_f && self.0.can_be_false.remove(idx) {
+                        changes += 1;
+                    }
+                    if ng_u && self.0.can_be_und.remove(idx) {
+                        changes += 1;
+                    }
+                    if self.0.can_be_true.contains(idx)
+                        || self.0.can_be_false.contains(idx)
+                        || self.0.can_be_und.contains(idx)
+                    {
+                        if changes > 0 {
+                            Conclusion::Update(self)
+                        } else {
+                            Conclusion::NoChange(self)
+                        }
+                    } else {
+                        // inconsistency
+                        Conclusion::Inconsistent(self)
+                    }
+                } else {
+                    Conclusion::NoChange(self)
+                }
+            }
+            // ng-consistency check might be possible
+            _ => {
+                if (scep_match & interpretation_active).len() == nogood_active.len() {
+                    Conclusion::Inconsistent(self)
+                } else {
+                    Conclusion::NoChange(self)
+                }
+            }
+        }
+    }
+    fn credulous_matches(&self, other: &NoGood) -> RoaringBitmap {
+        let true_match = (&self.0.can_be_true ^ &other.can_be_true) ^ self.0.full();
+        let false_match = (&self.0.can_be_false ^ &other.can_be_false) ^ self.0.full();
+        let und_match = (&self.0.can_be_und ^ &other.can_be_und) ^ self.0.full();
+
+        true_match | false_match | und_match
+    }
+
+    fn sceptical_matches(&self, other: &NoGood) -> RoaringBitmap {
+        let true_match = (&self.0.can_be_true ^ &other.can_be_true) ^ self.0.full();
+        let false_match = (&self.0.can_be_false ^ &other.can_be_false) ^ self.0.full();
+        let und_match = (&self.0.can_be_und ^ &other.can_be_und) ^ self.0.full();
+
+        true_match & false_match & und_match
+    }
+
+    /// Returns the credulous and sceptical matches of the [Interpretation] and a given [NoGood]
+    fn matches(&self, other: &NoGood) -> (RoaringBitmap, RoaringBitmap) {
+        let true_match = (&self.0.can_be_true ^ &other.can_be_true) ^ self.0.full();
+        let false_match = (&self.0.can_be_false ^ &other.can_be_false) ^ self.0.full();
+        let und_match = (&self.0.can_be_und ^ &other.can_be_und) ^ self.0.full();
+
+        (
+            &true_match | &false_match | &und_match,
+            true_match & false_match & und_match,
+        )
+    }
+}
+
+#[derive(Debug)]
+pub enum Conclusion {
+    Update(Interpretation),
+    NoChange(Interpretation),
+    Inconsistent(Interpretation),
+}
+
+impl Conclusion {
+    fn consistent(self) -> Option<Interpretation> {
+        match self {
+            Conclusion::Update(val) => Some(val),
+            Conclusion::NoChange(val) => Some(val),
+            Conclusion::Inconsistent(_) => None,
+        }
+    }
 }
 
 /// Representation of an Interpretation with Hints about truth-values.
-#[derive(Debug, Default, Clone)]
+#[derive(Debug, Clone)]
 pub struct NoGood {
     can_be_true: RoaringBitmap,
     can_be_false: RoaringBitmap,
     can_be_und: RoaringBitmap,
+    size: u32,
+}
+
+impl Default for NoGood {
+    fn default() -> Self {
+        Self {
+            can_be_true: Default::default(),
+            can_be_false: Default::default(),
+            can_be_und: Default::default(),
+            size: Default::default(),
+        }
+    }
 }
 
 impl Eq for NoGood {}
 impl PartialEq for NoGood {
     fn eq(&self, other: &Self) -> bool {
-        (self.can_be_true.borrow() ^ other.can_be_true.borrow()).is_empty()
-            && (self.can_be_false.borrow() ^ other.can_be_false.borrow()).is_empty()
-            && (self.can_be_und.borrow() ^ other.can_be_und.borrow()).is_empty()
+        (&self.can_be_true ^ &other.can_be_true).is_empty()
+            && (&self.can_be_false ^ &other.can_be_false).is_empty()
+            && (&self.can_be_und ^ &other.can_be_und).is_empty()
     }
 }
 
@@ -52,22 +182,42 @@ impl From<Interpretation> for NoGood {
 
 impl NoGood {
     fn invert(mut self) -> Self {
-        self.can_be_true ^= RoaringBitmap::full();
-        self.can_be_false ^= RoaringBitmap::full();
-        self.can_be_und ^= RoaringBitmap::full();
+        self.can_be_true ^= self.full();
+        self.can_be_false ^= self.full();
+        self.can_be_und ^= self.full();
         self
     }
 
+    fn idx_as_triple(&self, idx: u32) -> (bool, bool, bool) {
+        (
+            self.can_be_true.contains(idx),
+            self.can_be_false.contains(idx),
+            self.can_be_und.contains(idx),
+        )
+    }
+
+    fn full(&self) -> RoaringBitmap {
+        let mut result = RoaringBitmap::default();
+        result.insert_range(0..self.size);
+        result
+    }
+
     /// Creates a [NoGood], based on the given Vector of [Terms][Term]
     pub fn from_term_vec(term_vec: &[Term]) -> Self {
         let mut result = Self {
-            can_be_true: RoaringBitmap::full(),
-            can_be_false: RoaringBitmap::full(),
-            can_be_und: RoaringBitmap::full(),
+            can_be_true: RoaringBitmap::default(),
+            can_be_false: RoaringBitmap::default(),
+            can_be_und: RoaringBitmap::default(),
+            size: TryInto::<u32>::try_into(term_vec.len()).expect("no-good learner implementation is based on the assumption that only u32::MAX-many variables are in place"),
         };
+        result.can_be_true.insert_range(0..result.size);
+        result.can_be_false.insert_range(0..result.size);
+        result.can_be_und.insert_range(0..result.size);
+        log::debug!("{:?}", result);
         term_vec.iter().enumerate().for_each(|(idx, val)| {
 	    let idx:u32 = idx.try_into().expect("no-good learner implementation is based on the assumption that only u32::MAX-many variables are in place");
             if val.is_truth_value() {
+		log::trace!("idx {idx} val: {val:?}");
                 if val.is_true() {
 		    result.can_be_false.remove(idx);
 		    result.can_be_und.remove(idx);
@@ -77,6 +227,139 @@ impl NoGood {
 		}
             }
         });
+        log::debug!("{:?}", result);
         result
     }
+
+    /// Returns the number of set variables.
+    pub fn len(&self) -> usize {
+        self.active()
+            .len()
+            .try_into()
+            .expect("Expecting to be on a 64 bit system")
+    }
+
+    fn active(&self) -> RoaringBitmap {
+        (&self.can_be_true & &self.can_be_false & &self.can_be_und) ^ &self.full()
+    }
+
+    fn no_matches(&self, other: &NoGood) -> RoaringBitmap {
+        let no_true_match = &self.can_be_true ^ &other.can_be_true;
+        let no_false_match = &self.can_be_false ^ &other.can_be_false;
+        let no_und_match = &self.can_be_und ^ &other.can_be_und;
+
+        no_true_match | no_false_match | no_und_match
+    }
+}
+#[cfg(test)]
+mod test {
+    use super::*;
+    use test_log::test;
+
+    #[test]
+    fn create_ng() {
+        let terms = vec![Term::TOP, Term(22), Term(13232), Term::BOT, Term::TOP];
+        let ng = NoGood::from_term_vec(&terms);
+
+        assert_eq!(terms.len(), 5);
+        assert_eq!(ng.size, 5);
+        log::debug!("{:?}", ng.active());
+        assert_eq!(ng.active().len(), 3);
+        assert_eq!(ng.idx_as_triple(0), (true, false, false));
+        assert_eq!(ng.idx_as_triple(1), (true, true, true));
+        assert_eq!(ng.idx_as_triple(2), (true, true, true));
+        assert_eq!(ng.idx_as_triple(3), (false, true, false));
+        assert_eq!(ng.idx_as_triple(4), (true, false, false));
+    }
+
+    #[test]
+    fn create_interpretation() {
+        let terms = vec![Term::TOP, Term(22), Term(13232), Term::BOT, Term::TOP];
+        let interpretation = Interpretation::from_term_vec(&terms);
+
+        assert_eq!(interpretation.active().len(), 3);
+        assert_eq!(interpretation.idx_as_triple(0), (true, false, false));
+        assert_eq!(interpretation.idx_as_triple(1), (true, true, true));
+        assert_eq!(interpretation.idx_as_triple(2), (true, true, true));
+        assert_eq!(interpretation.idx_as_triple(3), (false, true, false));
+        assert_eq!(interpretation.idx_as_triple(4), (true, false, false));
+    }
+
+    #[test]
+    fn conclude() {
+        let ng1 = Interpretation::from_term_vec(&[
+            Term::TOP,
+            Term(22),
+            Term::TOP,
+            Term::BOT,
+            Term::TOP,
+            Term(22),
+        ]);
+        let ng2 = Interpretation::from_term_vec(&[
+            Term::TOP,
+            Term(22),
+            Term(13232),
+            Term::BOT,
+            Term::TOP,
+            Term(22),
+        ]);
+        let ng3 = Interpretation::from_term_vec(&[
+            Term::TOP,
+            Term(22),
+            Term::BOT,
+            Term::BOT,
+            Term::TOP,
+            Term(22),
+        ]);
+
+        let mut ng4 = ng3.clone();
+        ng4.0.can_be_und.insert(2);
+        ng4.0.can_be_false.remove(2);
+
+        let ng_too_big = Interpretation::from_term_vec(&[
+            Term::TOP,
+            Term(22),
+            Term::TOP,
+            Term::BOT,
+            Term::TOP,
+            Term::BOT,
+        ]);
+
+        assert!(ng1.clone().conclude(&ng2.0).consistent().is_none());
+        let result = ng2.clone().conclude(&ng1.0).consistent().unwrap();
+        assert_eq!(result.idx_as_triple(0), (true, false, false));
+        assert_eq!(result.idx_as_triple(1), (true, true, true));
+        assert_eq!(result.idx_as_triple(2), (false, true, true));
+        assert_eq!(result.idx_as_triple(3), (false, true, false));
+        assert_eq!(result.idx_as_triple(4), (true, false, false));
+
+        let result = result.conclude(&ng3.0).consistent().unwrap();
+        assert_eq!(result.idx_as_triple(0), (true, false, false));
+        assert_eq!(result.idx_as_triple(1), (true, true, true));
+        assert_eq!(result.idx_as_triple(2), (false, false, true));
+        assert_eq!(result.idx_as_triple(3), (false, true, false));
+        assert_eq!(result.idx_as_triple(4), (true, false, false));
+
+        assert!(result.conclude(&ng4.0).consistent().is_none());
+
+        let result = ng2
+            .clone()
+            .conclude(&ng1.0)
+            .consistent()
+            .and_then(|i| i.conclude(&ng4.0).consistent())
+            .unwrap();
+
+        assert_eq!(result.idx_as_triple(0), (true, false, false));
+        assert_eq!(result.idx_as_triple(1), (true, true, true));
+        assert_eq!(result.idx_as_triple(2), (false, true, false));
+        assert_eq!(result.idx_as_triple(3), (false, true, false));
+        assert_eq!(result.idx_as_triple(4), (true, false, false));
+
+        log::debug!("{:?}", ng2.clone().conclude(&ng_too_big.0));
+        if let Conclusion::NoChange(interpretation) = ng2.clone().conclude(&ng_too_big.0) {
+            assert_eq!(interpretation, ng2);
+        } else {
+            panic!("test failed");
+        }
+    }
 }