Package daikon.inv.unary.scalar

Class LowerBound

    • Field Detail

      • dkconfig_enabled

        public static boolean dkconfig_enabled
        Boolean. True iff LowerBound invariants should be considered.

      • dkconfig_minimal_interesting

        public static long dkconfig_minimal_interesting
        Long integer. Together with the corresponding maximal_interesting parameter, specifies the range of the computed constant that is ``interesting'' --- the range that should be reported. For instance, setting minimal_interesting to -1 and maximal_interesting to 2 would only permit output of LowerBound invariants whose cutoff was one of (-1,0,1,2).

      • dkconfig_maximal_interesting

        public static long dkconfig_maximal_interesting
        Long integer. Together with the corresponding minimal_interesting parameter, specifies the range of the computed constant that is ``interesting'' --- the range that should be reported. For instance, setting minimal_interesting to -1 and maximal_interesting to 2 would only permit output of LowerBound invariants whose cutoff was one of (-1,0,1,2).

    • Method Detail

      • get_proto

        public static LowerBound get_proto()
        Returns the prototype invariant for LowerBound

      • enabled

        public boolean enabled()
        Description copied from class: Invariant
        Returns whether or not this class of invariants is currently enabled.

        Its implementation is almost always return dkconfig_enabled;.

        Specified by:
        enabled in class Invariant

      • clone

        @SideEffectFree
public LowerBound clone​(@GuardSatisfied LowerBound this)
        Description copied from class: Invariant
        Do nothing special, Overridden to remove exception from declaration.
        Overrides:
        clone in class Invariant

      • min

        public long min()

      • repr

        public String repr​(@GuardSatisfied LowerBound this)
        Description copied from class: Invariant
        For printing invariants, there are two interfaces: repr gives a low-level representation (Invariant.repr_prob() also prints the confidence), and Invariant.format() gives a high-level representation for user output.
        Overrides:
        repr in class Invariant
        Returns:
        a string representation of this

      • check_modified

        public InvariantStatus check_modified​(long value,
                                      int count)
        Description copied from class: SingleScalar
        Presents a sample to the invariant. Returns whether the sample is consistent with the invariant. Does not change the state of the invariant.
        Specified by:
        check_modified in class SingleScalar
        count - how many identical samples were observed in a row. For example, three calls to check_modified with a count parameter of 1 is equivalent to one call to check_modified with a count parameter of 3.
        Returns:
        whether or not the sample is consistent with the invariant

      • enoughSamples

        public boolean enoughSamples​(@GuardSatisfied LowerBound this)
        Description copied from class: Invariant
        Returns true if the invariant has enough samples to have its computed constants well-formed. Is overridden in classes like LinearBinary/Ternary and Upper/LowerBound.
        Overrides:
        enoughSamples in class Invariant
        Returns:
        true if the invariant has enough samples to have its computed constants well-formed

      • isExact

        @Pure
public boolean isExact()
        Description copied from class: Invariant
        Subclasses should override. An exact invariant indicates that given all but one variable value, the last one can be computed. (I think that's correct, anyway.) Examples are IntComparison (when only equality is possible), LinearBinary, FunctionUnary. OneOf is treated differently, as an interface. The result of this method does not depend on whether the invariant is justified, destroyed, etc.
        Overrides:
        isExact in class Invariant
        Returns:
        true if any variable value can be computed from all the others

      • isSameFormula

        @Pure
public boolean isSameFormula​(Invariant other)
        Description copied from class: Invariant
        Returns true iff the two invariants represent the same mathematical formula. Does not consider the context such as variable names, confidences, sample counts, value counts, or related quantities. As a rule of thumb, if two invariants format the same, this method returns true. Furthermore, in many cases, if an invariant does not involve computed constants (as "x>c" and "y=ax+b" do for constants a, b, and c), then this method vacuously returns true.
        Specified by:
        isSameFormula in class Invariant
        Parameters:
        other - the invariant to compare to this one
        Returns:
        true iff the two invariants represent the same mathematical formula. Does not consider

      • hasUninterestingConstant

        public boolean hasUninterestingConstant()
        Description copied from class: Invariant
        An invariant that includes an uninteresting constant (say, "size(x[]) < 237") is likely to be an artifact of the way the program was tested, rather than a statement that would in fact hold over all possible executions.
        Overrides:
        hasUninterestingConstant in class Invariant

      • isObviousStatically

        @Pure
public @Nullable DiscardInfo isObviousStatically​(VarInfo[] vis)
        Description copied from class: Invariant
        Return true if this invariant is necessarily true from a fact that can be determined statically -- for the given varInfos rather than the varInfos of this. Conceptually, this means "is this invariant statically obvious if its VarInfos were switched with vis?" Intended to be overridden by subclasses. Should only do static checking.

        Precondition: vis.length == this.ppt.var_infos.length

        Overrides:
        isObviousStatically in class Invariant
        Parameters:
        vis - the VarInfos this invariant is obvious over. The position and data type of the variables is the *same* as that of this.ppt.var_infos.

      • isObviousDynamically

        @Pure
public @Nullable DiscardInfo isObviousDynamically​(VarInfo[] vis)
        Description copied from class: Invariant
        Return non-null if this invariant is necessarily true from a fact that can be determined dynamically (after checking data) -- for the given varInfos rather than the varInfos of this. Conceptually, this means, "Is this invariant dynamically obvious if its VarInfos were switched with vis?" Intended to be overriden by subclasses so they can filter invariants after checking; the overriding method should first call "super.isObviousDynamically(vis)". Since this method is dynamic, it should only be called after all processing.
        Overrides:
        isObviousDynamically in class Invariant

      • isExclusiveFormula

        @Pure
public boolean isExclusiveFormula​(Invariant other)
        Description copied from class: Invariant
        Returns true iff the two invariants represent mutually exclusive mathematical formulas -- that is, if one of them is true, then the other must be false. This method does not consider the context such as variable names, confidences, sample counts, value counts, or related quantities.
        Overrides:
        isExclusiveFormula in class Invariant
        Parameters:
        other - the other invariant to compare to this one
        Returns:
        true iff the two invariants represent mutually exclusive mathematical formulas

      • mergeFormulasOk

        public boolean mergeFormulasOk()
        Bound can merge different formulas from lower points to create a single formula at an upper point. See merge() below.
        Overrides:
        mergeFormulasOk in class Invariant
        Returns:
        true if invariants with different formulas can be merged

      • merge

        public @Nullable LowerBound merge​(List<Invariant> invs,
                                  PptSlice parent_ppt)
        Merge the invariants in invs to form a new invariant. Each must be a LowerBound invariant. This code finds all of the min/max values in each invariant, applies them to a new parent invariant and returns the merged invariant (if any).
        Overrides:
        merge in class Invariant
        Parameters:
        invs - list of invariants to merge. The invariants must all be of the same type and should come from the children of parent_ppt. They should also all be permuted to match the variable order in parent_ppt.
        parent_ppt - slice that will contain the new invariant
        Returns:
        the merged invariant or null if the invariants didn't represent the same invariant