add get-interpolant command

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

src/cmd_context/basic_cmds.cpp

@@ -31,6 +31,8 @@ Notes:
 #include "cmd_context/cmd_util.h"
 #include "cmd_context/simplify_cmd.h"
 #include "cmd_context/eval_cmd.h"
+#include "qe/qe_mbp.h"
+#include "qe/qe_mbi.h"
 
 class help_cmd : public cmd {
     svector<symbol> m_cmds;
@@ -849,6 +851,47 @@ public:
     void finalize(cmd_context & ctx) override {}
 };
 
+class get_interpolant_cmd : public cmd {
+    expr* m_a;
+    expr* m_b;
+public:
+    get_interpolant_cmd():cmd("get-interpolant") {}
+    char const * get_usage() const override { return "<expr> <expr>"; }
+    char const * get_descr(cmd_context & ctx) const override { return "perform model based interpolation"; }
+    unsigned get_arity() const override { return 2; }
+    cmd_arg_kind next_arg_kind(cmd_context& ctx) const override {
+        return CPK_EXPR; 
+    }
+    void set_next_arg(cmd_context& ctx, expr * arg) override { 
+        if (m_a == nullptr) 
+            m_a = arg; 
+        else 
+            m_b = arg; 
+    }
+    void prepare(cmd_context & ctx) override { m_a = nullptr; m_b = nullptr;  }
+    void execute(cmd_context & ctx) override { 
+        ast_manager& m = ctx.m();
+        qe::interpolator mbi(m);
+        expr_ref a(m_a, m);
+        expr_ref b(m_b, m);
+        expr_ref itp(m);
+        solver_factory& sf = ctx.get_solver_factory();
+        params_ref p;
+        solver_ref sA = sf(m, p, false /* no proofs */, true, true, symbol::null);
+        solver_ref sB = sf(m, p, false /* no proofs */, true, true, symbol::null);
+        solver_ref sNotA = sf(m, p, false /* no proofs */, true, true, symbol::null);
+        sA->assert_expr(a);
+        sB->assert_expr(b);
+        qe::uflia_mbi pA(sA.get(), sNotA.get());
+        qe::prop_mbi_plugin pB(sB.get());
+        pA.set_shared(a, b);
+        pB.set_shared(a, b);
+        lbool res = mbi.pogo(pA, pB, itp);
+        ctx.regular_stream() << res << " " << itp << "\n";
+    }
+};
+
+
 // provides "help" for builtin cmds
 class builtin_cmd : public cmd {
     char const * m_usage;
@@ -898,6 +941,7 @@ void install_ext_basic_cmds(cmd_context & ctx) {
     ctx.insert(alloc(echo_cmd));
     ctx.insert(alloc(labels_cmd));
     ctx.insert(alloc(declare_map_cmd));
+    ctx.insert(alloc(get_interpolant_cmd));
     ctx.insert(alloc(builtin_cmd, "reset", nullptr, "reset the shell (all declarations and assertions will be erased)"));
     install_simplify_cmd(ctx);
     install_eval_cmd(ctx);

src/math/polynomial/algebraic_numbers.cpp

@@ -1839,9 +1839,11 @@ namespace algebraic_numbers {
            m_compare_sturm++;
            upolynomial::scoped_upolynomial_sequence seq(upm());
            upm().sturm_tarski_seq(cell_a->m_p_sz, cell_a->m_p, cell_b->m_p_sz, cell_b->m_p, seq);
-           int V = upm().sign_variations_at(seq, a_lower) - upm().sign_variations_at(seq, a_upper);
+           unsigned V1 = upm().sign_variations_at(seq, a_lower);
+           unsigned V2 = upm().sign_variations_at(seq, a_upper); 
+           int V =  V1 - V2;
            TRACE("algebraic", tout << "comparing using sturm\n"; display_interval(tout, a); tout << "\n"; display_interval(tout, b); tout << "\n";
-                 tout << "V: " << V << ", sign_lower(a): " << sign_lower(cell_a) << ", sign_lower(b): " << sign_lower(cell_b) << "\n";);
+                 tout << "V: " << V << " V1 " << V1 << " V2 " << V2 << " sign_lower(a): " << sign_lower(cell_a) << ", sign_lower(b): " << sign_lower(cell_b) << "\n";);
            if (V == 0)
                return sign_zero;
            if ((V < 0) == (sign_lower(cell_b) < 0))

src/nlsat/nlsat_interval_set.cpp

@@ -169,54 +169,58 @@ namespace nlsat {
         return new_set;
     }
 
-    inline int compare_lower_lower(anum_manager & am, interval const & i1, interval const & i2) {
+    inline ::sign compare_lower_lower(anum_manager & am, interval const & i1, interval const & i2) {
         if (i1.m_lower_inf && i2.m_lower_inf)
-            return 0;
+            return sign_zero;
         if (i1.m_lower_inf)
-            return -1;
+            return sign_neg;
         if (i2.m_lower_inf)
-            return 1;
+            return sign_pos;
         SASSERT(!i1.m_lower_inf && !i2.m_lower_inf);
-        int s = am.compare(i1.m_lower, i2.m_lower);
+        ::sign s = am.compare(i1.m_lower, i2.m_lower);
-        if (s != 0)
+        if (!is_zero(s)) 
             return s;
         if (i1.m_lower_open == i2.m_lower_open)
-            return 0;
+            return sign_zero;
         if (i1.m_lower_open)
-            return 1;
+            return sign_pos;
         else
-            return -1;
+            return sign_neg;
     }
 
-    inline int compare_upper_upper(anum_manager & am, interval const & i1, interval const & i2) {
+    inline ::sign compare_upper_upper(anum_manager & am, interval const & i1, interval const & i2) {
         if (i1.m_upper_inf && i2.m_upper_inf)
-            return 0;
+            return sign_zero;
         if (i1.m_upper_inf)
-            return 1;
+            return sign_pos;
         if (i2.m_upper_inf)
-            return -1;
+            return sign_neg;
         SASSERT(!i1.m_upper_inf && !i2.m_upper_inf);
-        int s = am.compare(i1.m_upper, i2.m_upper);
+        auto s = am.compare(i1.m_upper, i2.m_upper);
-        if (s != 0)
+        if (!::is_zero(s)) 
             return s;
         if (i1.m_upper_open == i2.m_upper_open)
-            return 0;
+            return sign_zero;
         if (i1.m_upper_open)
-            return -1;
+            return sign_neg;
         else
-            return 1;
+            return sign_pos;
     }
 
-    inline int compare_upper_lower(anum_manager & am, interval const & i1, interval const & i2) {
+    inline ::sign compare_upper_lower(anum_manager & am, interval const & i1, interval const & i2) {
-        if (i1.m_upper_inf || i2.m_lower_inf)
+        if (i1.m_upper_inf || i2.m_lower_inf) {
-            return 1;
+            TRACE("nlsat_interval", nlsat::display(tout << "i1: ", am, i1); nlsat::display(tout << "i2: ", am, i2););
+            return sign_pos;
+        }
         SASSERT(!i1.m_upper_inf && !i2.m_lower_inf);
-        int s = am.compare(i1.m_upper, i2.m_lower);
+        auto s = am.compare(i1.m_upper, i2.m_lower);
-        if (s != 0)
+        TRACE("nlsat_interval", nlsat::display(tout << "i1: ", am, i1); nlsat::display(tout << " i2: ", am, i2); 
+              tout << " compare: " << s << "\n";);
+        if (!::is_zero(s))
             return s;
         if (!i1.m_upper_open && !i2.m_lower_open)
-            return 0;
+            return sign_zero;
-        return -1;
+        return sign_neg;
     }
     
     typedef sbuffer<interval, 128> interval_buffer;
@@ -227,9 +231,9 @@ namespace nlsat {
     bool adjacent(anum_manager & am, interval const & curr, interval const & next) {
         SASSERT(!curr.m_upper_inf);
         SASSERT(!next.m_lower_inf);
-        int sign = am.compare(curr.m_upper, next.m_lower);
+        auto sign = am.compare(curr.m_upper, next.m_lower);
-        SASSERT(sign <= 0);
+        SASSERT(sign != sign_pos);
-        if (sign == 0) {
+        if (is_zero(sign)) {
             SASSERT(curr.m_upper_open || next.m_lower_open);
             return !curr.m_upper_open || !next.m_lower_open;
         }
@@ -271,6 +275,15 @@ namespace nlsat {
     }
 
     interval_set * interval_set_manager::mk_union(interval_set const * s1, interval_set const * s2) {
+#if 0
+        // issue #2867:
+        static unsigned s_count = 0;
+        s_count++;
+        if (s_count == 8442) {
+            enable_trace("nlsat_interval");
+            enable_trace("algebraic");
+        }
+#endif
         TRACE("nlsat_interval", tout << "mk_union\ns1: "; display(tout, s1); tout << "\ns2: "; display(tout, s2); tout << "\n";);
         if (s1 == nullptr || s1 == s2)
             return const_cast<interval_set*>(s2);
@@ -421,7 +434,7 @@ namespace nlsat {
                     // i2 may consume other intervals of s1
                 }
                 else {
-                    int u2_l1_sign = compare_upper_lower(m_am, int2, int1);
+                    auto u2_l1_sign = compare_upper_lower(m_am, int2, int1);
                     if (u2_l1_sign < 0) {
                         TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign > 0, u2_l1_sign < 0\n";);
                         // Case:
@@ -430,7 +443,7 @@ namespace nlsat {
                         push_back(m_am, result, int2);
                         i2++;
                     }
-                    else if (u2_l1_sign == 0) {
+                    else if (is_zero(u2_l1_sign)) {
                         TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign > 0, u2_l1_sign == 0\n";);
                         SASSERT(!int1.m_lower_open && !int2.m_upper_open);
                         SASSERT(!int1.m_lower_inf);

src/qe/qe_mbi.cpp

@@ -29,6 +29,7 @@ Notes:
 --*/
 
 #include "ast/ast_util.h"
+#include "ast/ast_pp.h"
 #include "ast/for_each_expr.h"
 #include "ast/rewriter/expr_safe_replace.h"
 #include "ast/rewriter/bool_rewriter.h"
@@ -43,6 +44,38 @@ Notes:
 
 namespace qe {
 
+    void mbi_plugin::set_shared(expr* a, expr* b) {
+        TRACE("qe", tout << mk_pp(a, m) << " " << mk_pp(b, m) << "\n";);
+        struct fun_proc {
+            obj_hashtable<func_decl> s;
+            void operator()(app* a) { if (is_uninterp(a)) s.insert(a->get_decl()); }
+            void operator()(expr*) {}
+        };
+        fun_proc symbols_in_a;
+        expr_fast_mark1 marks;
+        quick_for_each_expr(symbols_in_a, marks, a);
+        marks.reset();
+        m_shared_trail.reset();
+        m_shared.reset();
+        m_is_shared.reset();
+        
+        struct intersect_proc {
+            mbi_plugin& p;
+            obj_hashtable<func_decl>& sA;
+            intersect_proc(mbi_plugin& p, obj_hashtable<func_decl>& sA):p(p), sA(sA) {}
+            void operator()(app* a) { 
+                func_decl* f = a->get_decl();
+                if (sA.contains(f) && !p.m_shared.contains(f)) {
+                    p.m_shared_trail.push_back(f);
+                    p.m_shared.insert(f);
+                }
+            }
+            void operator()(expr*) {}
+        };
+        intersect_proc symbols_in_b(*this, symbols_in_a.s);
+        quick_for_each_expr(symbols_in_b, marks, b);
+    }
+
     lbool mbi_plugin::check(expr_ref_vector& lits, model_ref& mdl) {
         while (true) {
             switch ((*this)(lits, mdl)) {

src/qe/qe_mbi.h

@@ -21,6 +21,7 @@ Revision History:
 #pragma once
 
 #include "qe/qe_arith.h"
+#include "util/lbool.h"
 
 namespace qe {
     enum mbi_result {
@@ -54,6 +55,8 @@ namespace qe {
             for (auto* f : vars) m_shared.insert(f);
         }
 
+        void set_shared(expr* a, expr* b);
+
         /**
          * Set representative (shared) expression finder.
          */