value sweep

Author: NikolajBjorner

src/ast/rewriter/CMakeLists.txt

@@ -33,6 +33,7 @@ z3_add_component(rewriter
     rewriter.cpp
     seq_rewriter.cpp
     th_rewriter.cpp
+    value_sweep.cpp
     var_subst.cpp
     mk_extract_proc.cpp
   COMPONENT_DEPENDENCIES

src/ast/rewriter/value_sweep.cpp

@@ -0,0 +1,158 @@
+/*++
+  Copyright (c) 2020 Microsoft Corporation
+
+  Module Name:
+
+    value_sweep.cpp
+
+  Author:
+
+    Nikolaj Bjorner 2020-04-25
+
+--*/
+
+#include "ast/for_each_expr.h"
+#include "ast/ast_pp.h"
+#include "ast/rewriter/value_sweep.h"
+
+value_sweep::value_sweep(ast_manager& m):
+    m(m),
+    m_gen(m),
+    m_rec(m),
+    m_dt(m),
+    m_rewrite(m),
+    m_values(m),
+    m_args(m),
+    m_pinned(m),
+    m_rounds(10),
+    m_range(20),
+    m_qhead(0)
+{}
+
+void value_sweep::set_value_core(expr* e, expr* v) {
+    m_values.reserve(e->get_id() + 1);
+    m_values[e->get_id()] = v;
+}
+
+void value_sweep::set_value(expr* e, expr* v) {
+    set_value_core(e, v);
+    m_pinned.push_back(e);
+}
+
+void value_sweep::reset_values() {
+    m_values.reset();
+    m_pinned.reset();
+}
+
+expr* value_sweep::get_value(expr* e) const {
+    if (m_values.size() <= e->get_id())
+        return nullptr;
+    return m_values[e->get_id()];
+}
+
+void value_sweep::unassign(unsigned sz) {
+    for (unsigned i = m_queue.size(); i-- > sz; ) {
+        expr* e = m_queue[i];
+        m_values[e->get_id()] = nullptr;
+    }
+    m_queue.shrink(sz);
+    m_qhead = sz;
+}
+
+bool value_sweep::assign_next_value() {
+    for (; m_vhead < m_vars.size(); ) {
+        expr* v = m_vars[m_vhead];
+        ++m_vhead;
+        if (!get_value(v)) {
+            unsigned index = m_rand() % m_range;
+            expr_ref val = m_gen.get_value(m.get_sort(v), index);
+            set_value_core(v, val);
+            m_queue.push_back(v);
+            return true;
+        }
+    }
+    return false;
+}
+
+bool value_sweep::is_reducible(expr* e) const {
+    if (!is_app(e))
+        return false;
+    app* a = to_app(e);
+    return 
+        m_rec.is_defined(a) ||
+        a->get_family_id() == m_dt.get_family_id() ||
+        a->get_family_id() == m.get_basic_family_id();    
+}
+
+bool value_sweep::all_args_have_values(app* p) const {
+    for (expr* arg : *p) {
+        if (!get_value(arg))
+            return false;
+    }
+    return true;
+}
+
+void value_sweep::propagate_values() {
+    for (; m_qhead < m_queue.size(); ++m_qhead) {
+        expr* e = m_queue[m_qhead];
+        for (app* p : m_parents[e->get_id()]) {
+            if (get_value(p))
+                continue;
+            if (!is_reducible(p))
+                continue;
+            if (!all_args_have_values(p))
+                continue;            
+            m_args.reset();
+            for (expr* arg : *p) 
+                m_args.push_back(get_value(arg));                                
+            expr_ref new_value(m.mk_app(p->get_decl(), m_args), m);
+            m_rewrite(new_value);
+            TRACE("value_sweep", tout << "propagate " << mk_pp(p, m) << " " << new_value << "\n";);
+            set_value_core(p, new_value);
+            m_queue.push_back(p);
+        }
+    }
+}
+
+void value_sweep::init(expr_ref_vector const& terms) { 
+    m_parents.reset();
+    m_queue.reset();
+    m_vars.reset();
+    m_qhead = 0;
+    m_vhead = 0;
+    for (expr* t : subterms(terms)) {
+        m_parents.reserve(t->get_id() + 1);
+        if (get_value(t)) 
+            m_queue.push_back(t);
+        else if (!is_reducible(t))
+            m_vars.push_back(t);
+    }
+    for (expr* t : subterms(terms)) {
+        if (!is_app(t)) 
+            continue;
+        for (expr* arg : *to_app(t)) 
+            m_parents[arg->get_id()].push_back(to_app(t));
+    }
+}
+
+void value_sweep::operator()(expr_ref_vector const& terms,
+                             vector<expr_ref_vector>& values) {
+
+    unsigned qhead0 = m_queue.size();
+    init(terms);
+    propagate_values();
+    unsigned qhead = m_queue.size();
+    for (unsigned i = 0; i < m_rounds; ++i) {
+        m_vhead = 0;
+        while (assign_next_value()) {
+            propagate_values();
+        }
+        expr_ref_vector vec(m);
+        for (expr* t : terms) {
+            vec.push_back(get_value(t));
+        }
+        values.push_back(vec);
+        unassign(qhead);
+    }
+    unassign(qhead0);
+}

src/ast/rewriter/value_sweep.h

@@ -0,0 +1,73 @@
+/*++
+  Copyright (c) 2020 Microsoft Corporation
+
+  Module Name:
+
+   value_sweep.h
+
+  Abstract:
+   
+    Evaluate terms using different random initial assignments.
+    Return the assignments.
+
+  Author:
+
+    Nikolaj Bjorner 2020-04-27
+  
+--*/
+
+#pragma once
+
+#include "ast/value_generator.h"
+#include "ast/recfun_decl_plugin.h"
+#include "ast/datatype_decl_plugin.h"
+#include "ast/rewriter/th_rewriter.h"
+
+class value_sweep {
+    typedef vector<ptr_vector<app>> parents_t;
+
+    ast_manager&     m;
+    value_generator  m_gen;
+    recfun::util     m_rec;
+    datatype::util   m_dt;
+    th_rewriter      m_rewrite;
+    expr_ref_vector  m_values;
+    expr_ref_vector  m_args;
+    expr_ref_vector  m_pinned;
+    unsigned         m_rounds;
+    unsigned         m_range;
+    random_gen       m_rand;
+    
+    parents_t        m_parents;
+    ptr_vector<expr> m_queue;
+    ptr_vector<expr> m_vars;
+    unsigned         m_qhead;
+    unsigned         m_vhead;
+   
+    void init(expr_ref_vector const& terms);
+
+    void set_value_core(expr* e, expr* v);
+
+    expr* get_value(expr* e) const;
+
+    void unassign(unsigned qhead);
+
+    void propagate_values();
+
+    bool assign_next_value();
+
+    bool is_reducible(expr* e) const;
+
+    bool all_args_have_values(app* p) const;
+    
+
+ public:
+    value_sweep(ast_manager& m);
+    void set_rounds(unsigned r) { m_rounds = r; }
+    void set_range(unsigned r) { m_range = r; }
+    void set_value(expr* e, expr* v);
+    void reset_values();
+
+    void operator()(expr_ref_vector const& terms,
+                    vector<expr_ref_vector>& values);
+};

src/test/CMakeLists.txt

@@ -123,6 +123,7 @@ add_executable(test-z3
   uint_set.cpp
   upolynomial.cpp
   value_generator.cpp
+  value_sweep.cpp
   var_subst.cpp
   vector.cpp
   lp/lp.cpp

src/test/main.cpp

@@ -218,6 +218,7 @@ int main(int argc, char ** argv) {
     TST(ext_numeral);
     TST(interval);
     TST(value_generator);
+    TST(value_sweep);
     TST(vector);
     TST(f2n);
     TST(hwf);

src/test/value_sweep.cpp

@@ -0,0 +1,37 @@
+#include "ast/rewriter/value_sweep.h"
+#include "ast/reg_decl_plugins.h"
+#include "ast/ast_pp.h"
+#include "ast/seq_decl_plugin.h"
+#include "ast/array_decl_plugin.h"
+
+void tst_value_sweep() {
+    ast_manager m;
+    reg_decl_plugins(m);
+    datatype_util dt(m);
+    arith_util a(m);
+    array_util ar(m);
+    seq_util seq(m);
+    sort_ref int_sort(a.mk_int(), m);
+    func_decl_ref cons(m), is_cons(m), head(m), tail(m), nil(m), is_nil(m);
+
+    sort_ref ilist = dt.mk_list_datatype(int_sort, symbol("ilist"), 
+                                     cons, is_cons, head, tail, nil, is_nil);
+
+    expr_ref n(m.mk_const("n", int_sort), m);
+    expr_ref v1(m.mk_const("v1", ilist), m);
+    expr_ref v2(m.mk_const("v2", ilist), m);
+    std::cout << cons << "\n";
+    expr_ref v3(m.mk_app(cons.get(), n, v1), m);
+    expr_ref_vector terms(m);
+    terms.push_back(v1).push_back(v2).push_back(v3);
+    vector<expr_ref_vector> values;
+    value_sweep ws(m);
+    ws.set_range(30);
+    ws(terms, values);
+    for (auto const& vec : values) {
+        for (expr* v : vec) {
+            std::cout << mk_pp(v, m) << "\n";
+        }
+        std::cout << "\n";
+    }
+}