First fully running version of the prototype

Signed-off-by: Stefan Ellmauthaler <stefan.ellmauthaler@tu-dresden.de>

README.md

@@ -1,3 +1,20 @@
-# OBDD - ordered binary decision diagram
+# Prototype-solver for ADFs grounded semantics by utilising OBDDs - ordered binary decision diagrams
+
+
+## Abstract Dialectical Frameworks
+An abstract dialectical framework (ADF) consists of abstract statements. Each statement has an unique label and might be related to other statements (s) in the ADF. This relation is defined by a so-called acceptance condition (ac), which intuitively is a propositional formula, where the variable symbols are the labels of the statements. An interpretation is a three valued function which maps to each statement a truth value (true, false, undecided). We call such an interpretation a model, if each acceptance condition agrees to the interpration. 
+## ordered Binary Decision Diagram
+An ordered binary decision diagram is a normalised representation of binary functions, where satisfiability- and validity checks can be done relatively cheap.
+
+## Input-file format:
+Each statement is defined by an ASP-style unary predicate s, where the enclosed term represents the label of the statement.
+The binary predicate ac relates each statement to one propositional formula in prefix notation, with the logical operations and constants as follows:
+- and(x,y): conjunction
+- or(x,y): disjunctin
+- iff(x,Y): if and only if
+- xor(x,y): exclusive or
+- neg(x): classical negation
+- c(v): constant symbol "verum" - tautology/top
+- c(f): constant symbol "falsum" - inconsistency/bot
+
 
-An ordered binary decision diagram is a normalised representation of binary functions, where satisfiability- and validity checks can be done relatively cheap.

src/adf.rs

@@ -27,7 +27,7 @@ impl Statement {
     }
 }
 
-struct Adf {
+pub struct Adf {
     bdd: Bdd,
     stmts: Vec<Statement>,
     dict: HashMap<String, usize>, // label to pos in vec
@@ -37,7 +37,7 @@ impl Adf {
     pub fn new() -> Self {
         Adf {
             bdd: Bdd::new(),
-            stmts: Vec::new(),
+            stmts: Vec::new(),   
             dict: HashMap::new(),
         }
     }
@@ -45,12 +45,19 @@ impl Adf {
     fn add_statement(&mut self, statement: &str) {
         if self.dict.get(statement).is_none() {
             let pos = self.stmts.len();
+            //self.bdd.variable(pos);
+            //self.stmts
+            //    .push(Statement::new(statement, pos.clone()));
             self.stmts
-                .push(Statement::new(statement, self.bdd.variable(pos).clone()));
+               .push(Statement::new(statement, self.bdd.variable(pos).clone()));
             self.dict.insert(self.stmts[pos].label.to_string(), pos);
         }
     }
 
+    /// Initialise statements
+    ///
+    /// The order of statements given as a parameter will determine die ordering for the OBDD. 
+    /// Note that only initialised statements will regocnised as variables later on
     pub fn init_statements(&mut self, stmts: Vec<&str>) -> usize {
         for i in stmts.iter() {
             self.add_statement(*i);
@@ -58,6 +65,9 @@ impl Adf {
         self.stmts.len()
     }
 
+    /// Adds to a given statement its acceptance condition.
+    /// 
+    /// This ac needs to be in the prefix notation for ADFs as defined by the DIAMOND implementation. 
     pub fn add_ac(&mut self, statement: &str, ac: &str) {
         if let Some(stmt) = self.dict.get(statement) {
           self.add_ac_by_number(*stmt, ac)
@@ -73,49 +83,149 @@ impl Adf {
         self.stmts[st].ac = Some(ac);
     }
 
-    fn parseformula(&mut self, ac: &str) -> usize {
+    pub fn grounded(&mut self) -> Vec<usize> {
-        if let Some(split) = ac.find(',') {
+        let mut interpretation: Vec<usize> = Vec::new();
-            let (l, r) = ac.split_at(split);
+        let mut change:bool = false;
-            let rterm = self.parseformula(&r[1..r.len() - 1]);
-            if ac.starts_with("and(") {
-                let lterm = self.parseformula(&l[4..]);
-                self.bdd.and(lterm, rterm)
-            } else if ac.starts_with("or(") {
-                let lterm = self.parseformula(&l[3..]);
-                self.bdd.or(lterm, rterm)
-            } else if ac.starts_with("iff(") {
-                let lterm = self.parseformula(&l[4..]);
-                let neglterm = self.bdd.not(lterm);
-                let negrterm = self.bdd.not(rterm);
-                let con1 = self.bdd.and(lterm, rterm);
-                let con2 = self.bdd.and(neglterm, negrterm);
 
-                self.bdd.or(con1, con2)
+        for it in self.stmts.iter(){
-            } else {
+            interpretation.push((*it).ac.unwrap())
-                //if ac.starts_with("xor("){
+        }
-                let lterm = self.parseformula(&l[4..]);
+        loop{
-                let neglterm = self.bdd.not(lterm);
+            change = false;
-                let negrterm = self.bdd.not(rterm);
+            for pos in 0..self.stmts.len()-1{
-                let con1 = self.bdd.and(neglterm, rterm);
+                let curint = interpretation.clone();
-                let con2 = self.bdd.and(lterm, negrterm);
+                match curint[pos] {
-
+                    super::obdd::BDD_BOT => {
-                self.bdd.or(con1, con2)
+                        if let Some(n) = self.setvarvalue(curint,self.bdd.nodes[self.stmts[pos].var].var(),false){
-            }
+                            interpretation.clone_from(&n);
-        } else {
+                            change = true;
-            if ac.starts_with("neg(") {
+                        }
-                let term = self.parseformula(&ac[4..ac.len() - 1]);
+                    },
-                self.bdd.not(term)
+                    super::obdd::BDD_TOP => {
-            } else if ac.eq("c(v)") {
+                        if let Some(n) = self.setvarvalue(curint,self.bdd.nodes[self.stmts[pos].var].var(),true){
-                self.bdd.constant(true)
+                            interpretation.clone_from(&n);
-            } else if ac.eq("c(f)") {
+                            change = true;
-                self.bdd.constant(false)
+                        }
-            } else {
+                    },
-                match self.dict.get(ac) {
+                    _ => (),
-                    Some(it) => self.stmts[*it].var,
-                    _ => unreachable!(),
                 }
             }
+            if !change {break;}
+            println!("bla");
         }
+        interpretation
+    }
+
+    fn setvarvalue(&mut self,interpretation:Vec<usize>, var:usize, val:bool) -> Option<Vec<usize>>{
+        let mut interpretation2:Vec<usize> = vec![0;interpretation.len()];
+        let mut change: bool = false;
+        for (pos,it) in interpretation.iter().enumerate(){
+            interpretation2[pos] = self.bdd.restrict(interpretation[pos], var, val);
+            if interpretation[pos] != interpretation2[pos]{
+                change = true
+            }
+        }
+        if change{
+            Some(interpretation2)
+        }else{
+            None
+        }
+    }
+
+    fn parseformula(&mut self, ac: &str) -> usize {
+        if ac.len() > 3 {
+            match &ac[..4] {
+                "and(" => {
+                    let (left, right) = Adf::findpairs(&ac[4..]);
+                    let lterm = self.parseformula(left);
+                    let rterm = self.parseformula(right);
+                    return self.bdd.and(lterm, rterm);
+                },
+                "iff(" => {
+                    let (left, right) = Adf::findpairs(&ac[4..]);
+                    let lterm = self.parseformula(left);
+                    let rterm = self.parseformula(right);
+                    let notlt = self.bdd.not(lterm);
+                    let notrt = self.bdd.not(rterm);
+                    let con1 = self.bdd.and(lterm, rterm);
+                    let con2 = self.bdd.and(notlt,notrt);
+                    return self.bdd.or(con1,con2);
+                },
+                "xor(" => {
+                    let (left, right) = Adf::findpairs(&ac[4..]);
+                    let lterm = self.parseformula(left);
+                    let rterm = self.parseformula(right);
+                    let notlt = self.bdd.not(lterm);
+                    let notrt = self.bdd.not(rterm);
+                    let con1 = self.bdd.and(notlt, rterm);
+                    let con2 = self.bdd.and(lterm,notrt);
+                    return self.bdd.or(con1,con2);
+                },
+                "neg(" => {
+                    let pos = Adf::findterm(&ac[4..]).unwrap()+4;
+                    let term = self.parseformula(&ac[4..pos]);
+                    return self.bdd.not(term);
+                },
+                "c(f)" => return self.bdd.constant(false),
+                "c(v)" => return self.bdd.constant(true),
+                _ if &ac[..3] == "or(" => {
+                    let (left, right) = Adf::findpairs(&ac[3..]);
+                    let lterm = self.parseformula(left);
+                    let rterm = self.parseformula(right);
+                    return self.bdd.or(lterm, rterm);
+                },
+                _ => (),
+            }
+            
+        }
+        match self.dict.get(ac) {
+            Some(it) => self.bdd.variable(*it),
+            _ => {println!("{}",ac); unreachable!()}
+        }
+    }
+
+    pub fn findpairs<'a>(formula: &'a str) -> (&'a str,&'a str){
+        let lpos = Adf::findterm(formula).unwrap();
+        let rpos = Adf::findterm(&formula[lpos+1..]).unwrap() + lpos;
+        (&formula[..lpos],&formula[lpos+1..rpos+1])
+    }
+
+    pub fn findterm_str<'a> (formula: &'a str) -> &'a str{
+        &formula[..Adf::findterm(formula).unwrap()]
+    }
+
+    fn findterm(formula: &str) -> Option<usize> {
+        let mut sqbrack: i16 = 0;
+        let mut cobrack: i16 = 0;
+
+        for (i,c) in formula.chars().enumerate() {
+            match c {
+                '(' => sqbrack += 1,
+                '[' => cobrack += 1,
+                ',' => {
+                    if sqbrack + cobrack == 0 {
+                        return Some(i);
+                    }
+                }
+                ')' => {
+                    if sqbrack > 0 {
+                        sqbrack -= 1;
+                    }else{
+                        return Some(i);
+                    }
+                }
+                ']' => {
+                    if cobrack > 0 {
+                        cobrack -= 1;
+                    }else{
+                        return Some(i);
+                    }
+                }
+                _ => (),
+
+            }
+        }
+        Some(formula.len())
     }
 }
 
@@ -148,6 +258,8 @@ mod test {
         assert_eq!(adf.parseformula("and(a,or(b,c))"), 6);
         assert_eq!(adf.parseformula("xor(a,b)"), 11);
         assert_eq!(adf.parseformula("or(c(f),b)"), 3); // is b
+
+        adf.parseformula("and(or(c(f),a),and(b,c))");
     }
 
     #[test]
@@ -162,6 +274,19 @@ mod test {
         adf.parseformula("and(a,or(b,d))");
     }
 
+    #[test]
+    fn findterm() {
+        assert_eq!(Adf::findterm("formula"),Some(7));
+        assert_eq!(Adf::findterm("and(a,b),or(a,b)"),Some(8));
+        assert_eq!(Adf::findterm("neg(atom(a.d.ee))"),Some(17));
+        assert_eq!(Adf::findterm("formula)"),Some(7));
+    }
+
+    #[test]
+    fn findpairs() {
+        assert_eq!(Adf::findpairs("a,or(b,c))"),("a","or(b,c)"));
+    }
+
     #[test]
     fn init_statements() {
         let mut adf = Adf::new();

src/main.rs

@@ -0,0 +1,64 @@
+use std::borrow::Borrow;
+use std::{env, process::exit};
+use std::fs::File;
+use std::io::{self, BufRead};
+use std::path::Path;
+
+pub mod obdd;
+pub mod adf;
+
+use adf::Adf;
+
+fn main() {
+  let args:Vec<String> = env::args().collect();
+  if args.len() != 2 {
+    eprintln!("No Filename given");
+    exit(1);
+  }
+  let mut statements: Vec<String> = Vec::new();
+  let mut ac: Vec<(String,String)> = Vec::new();
+  let path = Path::new(args[1].as_str());
+  if let Ok(lines) = read_lines(path){
+    for resline in lines {
+      if let Ok(line) = resline {
+        //let slice = line.as_str();
+        if line.starts_with("s("){
+         // let slice = line.as_str();
+         // statements.push(Adf::findterm_str(&slice[2..]).clone());
+          statements.push(String::from(Adf::findterm_str(&line[2..]).replace(" ", "")));
+        }
+        else if line.starts_with("ac("){      
+          let (s,c) = Adf::findpairs(&line[3..]);
+          ac.push((String::from(s.replace(" ","")),String::from(c.replace(" ", ""))));
+        }
+      }
+    }
+  }
+
+  println!("parsed {} statements", statements.len());
+  if statements.len() > 0 && ac.len() > 0 {
+    let mut myAdf = Adf::new();
+    myAdf.init_statements(statements.iter().map(AsRef::as_ref).collect());
+    for (s,c) in ac {
+      myAdf.add_ac(s.as_str(), c.as_str());
+    }
+
+    let result = myAdf.grounded();
+    println!("{:?}",result);
+    for (p,s) in statements.iter().enumerate(){
+      match result[p] {
+        0 => print!("f("),
+        1 => print!("t("),
+        _ => print!("u("),
+      }
+      print!("{}) ",*s);
+    }
+
+  }
+}
+
+fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where P: AsRef<Path>, {
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}

src/obdd.rs

@@ -8,7 +8,7 @@ use std::collections::HashMap;
 type Term = usize;
 
 #[derive(Eq, PartialEq, Hash, Clone, Copy)]
-struct BddNode {
+pub (crate) struct BddNode {
     var: usize,
     lo: Term,
     hi: Term,
@@ -20,8 +20,14 @@ impl std::fmt::Display for BddNode {
     }
 }
 
+impl BddNode{
+    pub fn var(self)->usize{
+        self.var
+    }
+}
+
 pub (crate) struct Bdd {
-    nodes: Vec<BddNode>,
+    pub (crate) nodes: Vec<BddNode>,
     hash: HashMap<BddNode, Term>,
 }
 
@@ -79,7 +85,7 @@ impl Bdd {
         }
     }
 
-    fn restrict(&mut self, subtree: Term, var: usize, val: bool) -> Term {
+    pub fn restrict(&mut self, subtree: Term, var: usize, val: bool) -> Term {
         let treenode = self.nodes[subtree];
         if treenode.var > var || treenode.var == usize::MAX {
             subtree