diff --git a/src/main.rs b/src/main.rs
index f276d46..ebffe6b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,6 +5,7 @@
 mod random;
 
 use clap::{arg, Parser};
+use patronus::ir::{replace_anonymous_inputs_with_zero, simplify_expressions};
 use patronus::*;
 use random::*;
 
@@ -27,7 +28,13 @@ static RANDOM_OPTS: RandomOptions = RandomOptions {
 
 fn main() {
     let args = Args::parse();
-    let (mut ctx, sys) = btor2::parse_file(&args.filename).expect("Failed to load btor2 file!");
+
+    // load system
+    let (mut ctx, mut sys) = btor2::parse_file(&args.filename).expect("Failed to load btor2 file!");
+
+    // simplify system
+    replace_anonymous_inputs_with_zero(&mut ctx, &mut sys);
+    simplify_expressions(&mut ctx, &mut sys);
 
     // try random testing
     match random_testing(&mut ctx, sys, RANDOM_OPTS) {
diff --git a/src/random.rs b/src/random.rs
index 0093ada..af305ff 100644
--- a/src/random.rs
+++ b/src/random.rs
@@ -4,7 +4,10 @@
 //
 // Random testing strategy to finding counter examples.
 
-use patronus::ir::{Context, GetNode, SerializableIrNode, TransitionSystem, TypeCheck};
+use patronus::ir::{
+    cone_of_influence, cone_of_influence_comb, cone_of_influence_init, Context, ExprRef, GetNode,
+    SerializableIrNode, TransitionSystem, TypeCheck,
+};
 use patronus::sim;
 
 #[derive(Debug, Copy, Clone)]
@@ -28,22 +31,69 @@ pub fn random_testing(
     let sim_ctx = ctx.clone();
     let mut sim = sim::interpreter::Interpreter::new(&sim_ctx, &sys);
 
-    // show all inputs
-    let inputs = sys.get_signals(|s| s.is_input());
-    println!("INPUTS:");
-    for (expr_ref, input) in inputs.iter() {
-        let expr = ctx.get(*expr_ref);
-        println!("{} : {:?}", expr.serialize_to_str(ctx), expr.get_type(ctx));
-    }
+    // // show all inputs
+    // let inputs = sys.get_signals(|s| s.is_input());
+    // println!("INPUTS:");
+    // for (expr_ref, input) in inputs.iter() {
+    //     let expr = ctx.get(*expr_ref);
+    //     println!("{} : {:?}", expr.serialize_to_str(ctx), expr.get_type(ctx));
+    // }
+    //
+    // // show all states
+    // println!("\nSTATES:");
+    // for (state_ref, state) in sys.states() {
+    //     let expr = ctx.get(state.symbol);
+    //     println!("{} : {:?}", expr.serialize_to_str(ctx), expr.get_type(ctx));
+    // }
 
-    // show all states
-    println!("\nSTATES:");
-    for (state_ref, state) in sys.states() {
-        let expr = ctx.get(state.symbol);
-        println!("{} : {:?}", expr.serialize_to_str(ctx), expr.get_type(ctx));
-    }
+    // show system
+    println!("{}", sys.serialize_to_str(ctx));
+
+    // analyze constraint dependencies
+    let constraints = analyze_constraints(ctx, &sys, false);
+    println!("{constraints:?}");
 
     // TODO
 
     RandomResult::None
 }
+
+struct Constraints {
+    /// Single input constraints can be checked when we are sampling the input.
+    /// The tuple is (constraint ref, input ref)
+    single_input: Vec<(ExprRef, ExprRef)>,
+    /// State only constraints which we essentially just need to check once and give up if they fail.
+    state_only: Vec<ExprRef>,
+    /// All other constraints we currently rejection sample after an input has been chosen.
+    others: Vec<ExprRef>,
+}
+
+#[derive(Debug, Clone)]
+struct Constraint {
+    expr: ExprRef,
+    inputs: Vec<ExprRef>,
+    states: Vec<ExprRef>,
+}
+
+/// Check to see which constraints we can fulfill
+fn analyze_constraints(ctx: &Context, sys: &TransitionSystem, init: bool) -> Vec<Constraint> {
+    let states = sys.state_map();
+    let mut out = Vec::new();
+    // we want to see which constraints depends on which inputs
+    for (expr_ref, info) in sys.constraints() {
+        //
+        let cone = if init {
+            cone_of_influence_init(ctx, sys, expr_ref)
+        } else {
+            cone_of_influence_comb(ctx, sys, expr_ref)
+        };
+        let (states, inputs) = cone.iter().partition(|e| states.contains_key(e));
+        let constraint = Constraint {
+            expr: expr_ref,
+            inputs,
+            states,
+        };
+        out.push(constraint);
+    }
+    out
+}