mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-14 14:55:25 +00:00
Code Activity

A rudimentary version of MathSAT optimization

Browse source 
Remarks:
(1) The core procedure accepts maximization only
(2) Add lazy initialization to min_maximize_cmd
(3) The procedure isn't working with composite objective yet.
This commit is contained in:
Anh-Dung Phan 2013-10-18 18:00:24 -07:00
parent 898609a3ef
commit a44044fb15
8 changed files with 114 additions and 33 deletions
Download patch file Download diff file Expand all files Collapse all files

44
src/opt/opt_cmds.cpp
View file

@ -22,18 +22,32 @@ Notes:
#include "opt_context.h"
class opt_context {
cmd_context& ctx;
scoped_ptr<opt::context> m_opt;
public:
opt_context(cmd_context& ctx): ctx(ctx) {}
opt::context& operator()() {
if (!m_opt) {
m_opt = alloc(opt::context, ctx.m());
}
return *m_opt;
}
};
class assert_weighted_cmd : public cmd {
opt::context* m_opt_ctx;
opt_context* m_opt_ctx;
unsigned m_idx;
expr_ref m_formula;
expr* m_formula;
rational m_weight;
public:
assert_weighted_cmd(cmd_context& ctx, opt::context* opt_ctx):
assert_weighted_cmd(cmd_context& ctx, opt_context* opt_ctx):
cmd("assert-weighted"),
m_opt_ctx(opt_ctx),
m_idx(0),
m_formula(ctx.m()),
m_formula(0),
m_weight(0)
{}
@ -42,6 +56,9 @@ public:
}
virtual void reset(cmd_context & ctx) {
if (m_formula) {
ctx.m().dec_ref(m_formula);
}
m_idx = 0;
m_formula = 0;
}
@ -68,6 +85,7 @@ public:
throw cmd_exception("Invalid type for expression. Expected Boolean type.");
}
m_formula = t;
ctx.m().inc_ref(t);
++m_idx;
}
@ -76,7 +94,7 @@ public:
}
virtual void execute(cmd_context & ctx) {
m_opt_ctx->add_soft_constraint(m_formula, m_weight);
(*m_opt_ctx)().add_soft_constraint(m_formula, m_weight);
reset(ctx);
}
@ -91,10 +109,10 @@ public:
// to do the feasibility check.
class min_maximize_cmd : public cmd {
bool m_is_max;
opt::context* m_opt_ctx;
opt_context* m_opt_ctx;
public:
min_maximize_cmd(cmd_context& ctx, opt::context* opt_ctx, bool is_max):
min_maximize_cmd(cmd_context& ctx, opt_context* opt_ctx, bool is_max):
cmd(is_max?"maximize":"minimize"),
m_is_max(is_max),
m_opt_ctx(opt_ctx)
@ -113,7 +131,7 @@ public:
virtual void set_next_arg(cmd_context & ctx, expr * t) {
// TODO: type check objective term. It should pass basic sanity being
// integer, real (, bit-vector) or other supported objective function type.
m_opt_ctx->add_objective(t, m_is_max);
(*m_opt_ctx)().add_objective(t, m_is_max);
}
virtual void failure_cleanup(cmd_context & ctx) {
@ -127,9 +145,9 @@ public:
};
class optimize_cmd : public cmd {
opt::context* m_opt_ctx;
opt_context* m_opt_ctx;
public:
optimize_cmd(opt::context* opt_ctx):
optimize_cmd(opt_context* opt_ctx):
cmd("optimize"),
m_opt_ctx(opt_ctx)
{}
@ -145,9 +163,9 @@ public:
ptr_vector<expr>::const_iterator it = ctx.begin_assertions();
ptr_vector<expr>::const_iterator end = ctx.end_assertions();
for (; it != end; ++it) {
m_opt_ctx->add_hard_constraint(*it);
(*m_opt_ctx)().add_hard_constraint(*it);
}
m_opt_ctx->optimize();
(*m_opt_ctx)().optimize();
}
@ -157,7 +175,7 @@ private:
};
void install_opt_cmds(cmd_context & ctx) {
opt::context* opt_ctx = alloc(opt::context, ctx.m());
opt_context* opt_ctx = alloc(opt_context, ctx);
ctx.insert(alloc(assert_weighted_cmd, ctx, opt_ctx));
ctx.insert(alloc(min_maximize_cmd, ctx, opt_ctx, true));
ctx.insert(alloc(min_maximize_cmd, ctx, opt_ctx, false));