public virtual IntervalEnvironmentBase <TVar, TExpr, TInterval, TNumeric> AssumeEqual
(TExpr left,
TExpr right,
IntervalEnvironmentBase
<TVar,
TExpr,
TInterval,
TNumeric>
env)
{
var leftVar = env.Decoder.UnderlyingVariable(left);
var rightVar = env.Decoder.UnderlyingVariable(right);
if (env.Contains(leftVar))
{
var res = env;
var interval = env.Eval(left).Meet(env.Eval(right));
res = res.With(leftVar, interval);
res = res.With(rightVar, interval);
return(res);
}
if (env.Decoder.IsConstant(left) && env.Decoder.IsConstant(right) &&
env.Eval(left).Meet(env.Eval(right)).IsBottom)
{
return(env.Bottom);
}
return(env);
}
public override IntervalEnvironmentBase <Var, Expr, DisInterval, Rational> AssumeNotEqual
(Expr left, Expr right, IntervalEnvironmentBase <Var, Expr, DisInterval, Rational> env)
{
var result = env;
var rightIntv = env.Eval(right);
if (rightIntv.IsSinglePoint)
{
var everythingExcept = DisInterval.EverythingExcept(rightIntv);
result = result.RefineVariable(env.Decoder.UnderlyingVariable(left), everythingExcept);
}
IntervalInference.InferenceResult <Var, DisInterval> resultLeft;
IntervalInference.InferenceResult <Var, DisInterval> resultRight;
IntervalInference.ConstraintsFor.NotEqual(left, right, env.Decoder, result, out resultLeft,
out resultRight);
var join = resultLeft.Join(resultRight);
if (join.IsBottom)
{
return(env.Bottom as IntervalEnvironmentBase <Var, Expr, DisInterval, Rational>);
}
return(AssumeConstraints(join.Constraints, env));
}
public override IntervalEnvironmentBase <TVar, TExpr, TInterval, Rational> AssumeNotEqualToZero
(TExpr e,
IntervalEnvironmentBase
<
TVar
,
TExpr
,
TInterval
,
Rational
>
env)
{
var variable = env.Decoder.UnderlyingVariable(e);
var intv = env.Eval(e);
TInterval refinement;
if (intv.LowerBound.IsZero)
{
refinement = env.Context.For(1L, intv.UpperBound);
}
else if (intv.UpperBound.IsZero)
{
refinement = env.Context.For(intv.LowerBound, -1L);
}
else
{
refinement = env.Context.TopValue;
}
return(env.With(variable, intv.Meet(refinement)));
}
public override IntervalEnvironmentBase <TVar, TExpr, TInterval, TNumeric> Visit(TExpr expr,
IntervalEnvironmentBase
<TVar, TExpr,
TInterval,
TNumeric> data)
{
var res = base.Visit(expr, data);
if (!Decoder.IsBinaryExpression(expr))
{
return(res);
}
var left = Decoder.LeftExpressionFor(expr);
var right = Decoder.RightExpressionFor(expr);
var intv = data.Eval(right);
if (intv.IsBottom)
{
return(data.Bottom);
}
if (!intv.IsSinglePoint)
{
return(res);
}
switch (Decoder.OperatorFor(expr))
{
case ExpressionOperator.LessThan: {
var leftVar = Decoder.UnderlyingVariable(left);
return(res.Assumer.AssumeLessEqualThan(intv, leftVar, res));
}
case ExpressionOperator.LessEqualThan: {
var leftVar = Decoder.UnderlyingVariable(left);
return(res.Assumer.AssumeLessThan(intv, leftVar, res));
}
}
return(data);
}