missing file

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/ast/simplifiers/randomizer.h

@@ -0,0 +1,146 @@
+
+/*++
+Copyright (c) 2025 Microsoft Corporation
+
+Module Name:
+
+    randomizer.h
+
+Abstract:
+
+    Simplifier that randomizes formulas by renaming uninterpreted functions and permuting arguments of associative and commutative functions.
+
+Author:
+
+    Nikolaj Bjorner nbjorner 20-05-2025
+
+--*/
+
+#pragma once
+
+#include "ast/ast.h"
+#include "ast/ast_pp.h"
+#include "ast/simplifiers/dependent_expr_state.h"
+#include "util/obj_hashtable.h"
+#include <algorithm>
+
+class randomizer_simplifier : public dependent_expr_simplifier {
+    ast_manager& m;
+    obj_map<func_decl, func_decl*> m_rename;
+    ast_ref_vector   m_ast_trail;    
+    expr_ref_vector  m_new_exprs;
+    ptr_vector<expr> m_todo, m_args;
+    random_gen       m_rand;
+
+    func_decl* get_random_func_decl(func_decl* f) {
+        func_decl* r = nullptr;
+        if (m_rename.find(f, r))
+            return r;
+        // Create a new random name
+        std::string rand_name = f->get_name().str() + "_rand_" + std::to_string(m_rand());
+        symbol new_sym(rand_name.c_str());
+        r = m.mk_func_decl(new_sym, f->get_arity(), f->get_domain(), f->get_range());
+        m_rename.insert(f, r);
+        m_ast_trail.push_back(r);
+        m_ast_trail.push_back(f);
+        
+        m_trail.push(insert_obj_map(m_rename, f));
+        m_trail.push(push_back_vector(m_ast_trail));
+        m_trail.push(push_back_vector(m_ast_trail));
+
+
+        m_args.reset();
+        for (unsigned i = 0; i < f->get_arity(); ++i)
+            m_args.push_back(m.mk_var(i, f->get_domain(i)));
+        m_fmls.model_trail().hide(r);
+	    m_fmls.model_trail().push(f, m.mk_app(r, m_args), nullptr, {});
+        return r;        
+    }
+
+    void push_new_expr(expr* e, expr* new_e) {
+        m_new_exprs.setx(e->get_id(), new_e);
+        m_ast_trail.push_back(e);
+        m_trail.push(push_back_vector(m_ast_trail));
+        m_trail.push(set_vector_idx_trail(m_new_exprs, e->get_id()));
+        m_todo.pop_back();
+    }
+
+    expr* get_new_expr(expr* e) {
+        return m_new_exprs.get(e->get_id(), nullptr);
+    }
+
+    void randomize(expr* e) {
+        m_todo.push_back(e);
+        while (!m_todo.empty()) {
+            e = m_todo.back();
+            if (get_new_expr(e)) 
+                m_todo.pop_back();            
+            else if (is_app(e)) {
+                auto f = to_app(e)->get_decl();
+                // If uninterpreted function, rename
+                if (is_uninterp(f)) 
+                    f = get_random_func_decl(f);
+                m_args.reset();
+                auto arity = to_app(e)->get_num_args();
+                for (expr* arg : *to_app(e)) {
+                    expr* new_arg = get_new_expr(arg);
+                    if (new_arg)
+                        m_args.push_back(new_arg);
+                    else
+                        m_todo.push_back(arg);
+                }
+                if (m_args.size() < arity)
+                    continue;
+                if (f->is_associative() && f->is_commutative() && arity > 1) 
+                    shuffle(m_args.size(), m_args.data(), m_rand);
+                 expr_ref new_e(m.mk_app(f, m_args.size(), m_args.data()), m);
+                 push_new_expr(e, new_e);
+            }        
+            else if (is_quantifier(e)) {
+                quantifier* q = to_quantifier(e);
+                expr* body = q->get_expr();
+                expr* new_body = get_new_expr(body);
+                if (new_body) {
+                    expr_ref new_e(m.update_quantifier(q, new_body), m);
+                    push_new_expr(e, new_e);
+                }
+                else
+                    m_todo.push_back(body);
+            } 
+            else 
+                push_new_expr(e, e);                        
+        }
+    }
+
+public:
+    randomizer_simplifier(ast_manager& m, params_ref const & p, dependent_expr_state& fmls)
+        : dependent_expr_simplifier(m, fmls), m(m), m_ast_trail(m), m_new_exprs(m) {
+            // set m_rand reading from parameter?
+        }
+
+    char const* name() const override { return "randomizer"; }
+
+    void reduce() override {
+        for (unsigned idx : indices()) {
+            auto d = m_fmls[idx];
+            randomize(d.fml());
+            m_fmls.update(idx, dependent_expr(m, get_new_expr(d.fml()), d.pr(), d.dep()));
+        }
+        unsigned num_fmls = qtail() - qhead();
+        for (unsigned i = qhead(); i < qtail(); ++i) {
+            unsigned j = qhead() + m_rand(num_fmls);
+            if (i == j)
+                continue;
+            auto d1 = m_fmls[i];
+            auto d2 = m_fmls[j];
+            m_fmls.update(i, d2);
+            m_fmls.update(j, d1);
+        }
+    }
+
+    bool supports_proofs() const override { return false; }
+};
+
+/*
+  ADD_SIMPLIFIER("randomizer", "shuffle assertions and rename uninterpreted functions.", "alloc(randomizer_simplifier, m, p, s)")
+*/