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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
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Leonardo de Moura 2012-10-02 11:35:25 -07:00
parent 3f9edad676
commit e9eab22e5c
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104
lib/cost_evaluator.cpp Normal file
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/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
cost_evaluator.cpp
Abstract:
<abstract>
Author:
Leonardo de Moura (leonardo) 2008-06-14.
Revision History:
--*/
#include"cost_evaluator.h"
#include"warning.h"
cost_evaluator::cost_evaluator(ast_manager & m):
m_manager(m),
m_util(m) {
}
float cost_evaluator::eval(expr * f) const {
#define E(IDX) eval(to_app(f)->get_arg(IDX))
if (is_app(f)) {
unsigned num_args;
family_id fid = to_app(f)->get_family_id();
if (fid == m_manager.get_basic_family_id()) {
switch (to_app(f)->get_decl_kind()) {
case OP_TRUE: return 1.0f;
case OP_FALSE: return 0.0f;
case OP_NOT: return E(0) == 0.0f ? 1.0f : 0.0f;
case OP_AND:
num_args = to_app(f)->get_num_args();
for (unsigned i = 0; i < num_args; i++)
if (E(i) == 0.0f)
return 0.0f;
return 1.0f;
case OP_OR:
num_args = to_app(f)->get_num_args();
for (unsigned i = 0; i < num_args; i++)
if (E(i) != 0.0f)
return 1.0f;
return 0.0f;
case OP_ITE: return E(0) != 0.0f ? E(1) : E(2);
case OP_EQ:
case OP_IFF: return E(0) == E(1) ? 1.0f : 0.0f;
case OP_XOR: return E(0) != E(1) ? 1.0f : 0.0f;
case OP_IMPLIES:
if (E(0) == 0.0f)
return 1.0f;
return E(1) != 0.0f ? 1.0f : 0.0f;
default:
;
}
}
else if (fid == m_util.get_family_id()) {
switch (to_app(f)->get_decl_kind()) {
case OP_NUM: {
rational r = to_app(f)->get_decl()->get_parameter(0).get_rational();
return static_cast<float>(numerator(r).get_int64())/static_cast<float>(denominator(r).get_int64());
}
case OP_LE: return E(0) <= E(1) ? 1.0f : 0.0f;
case OP_GE: return E(0) >= E(1) ? 1.0f : 0.0f;
case OP_LT: return E(0) < E(1) ? 1.0f : 0.0f;
case OP_GT: return E(0) > E(1) ? 1.0f : 0.0f;
case OP_ADD: return E(0) + E(1);
case OP_SUB: return E(0) - E(1);
case OP_UMINUS: return - E(0);
case OP_MUL: return E(0) * E(1);
case OP_DIV: {
float q = E(1);
if (q == 0.0f) {
warning_msg("cost function division by zero");
return 1.0f;
}
return E(0) / q;
}
default:
;
}
}
}
else if (is_var(f)) {
unsigned idx = to_var(f)->get_idx();
if (idx < m_num_args)
return m_args[m_num_args - idx - 1];
}
warning_msg("cost function evaluation error");
return 1.0f;
}
float cost_evaluator::operator()(expr * f, unsigned num_args, float const * args) {
m_num_args = num_args;
m_args = args;
return eval(f);
}