Esempio n. 1
0
    def __new__(cls, *args, **kwargs):
        if len(args) == 1 and isinstance(args[0], LoweredEq):
            # origin: LoweredEq(devito.LoweredEq, **kwargs)
            input_expr = args[0]
            expr = sympy.Eq.__new__(cls, *input_expr.args, evaluate=False)
            for i in cls._state:
                setattr(expr, '_%s' % i, kwargs.get(i) or getattr(input_expr, i))
            return expr
        elif len(args) == 1 and isinstance(args[0], Eq):
            # origin: LoweredEq(devito.Eq)
            input_expr = expr = args[0]
        elif len(args) == 2:
            expr = sympy.Eq.__new__(cls, *args, evaluate=False)
            for i in cls._state:
                setattr(expr, '_%s' % i, kwargs.pop(i))
            return expr
        else:
            raise ValueError("Cannot construct LoweredEq from args=%s "
                             "and kwargs=%s" % (str(args), str(kwargs)))

        # Well-defined dimension ordering
        ordering = dimension_sort(expr)

        # Analyze the expression
        mapper = detect_accesses(expr)
        oobs = detect_oobs(mapper)
        conditionals = [i for i in ordering if i.is_Conditional]

        # The iteration space is constructed so that information always flows
        # from an iteration to another (i.e., no anti-dependences are created)
        directions, _ = force_directions(detect_flow_directions(expr), lambda i: Any)
        iterators = build_iterators(mapper)
        intervals = build_intervals(Stencil.union(*mapper.values()))
        intervals = IntervalGroup(intervals, relations=ordering.relations)
        ispace = IterationSpace(intervals.zero(), iterators, directions)

        # The data space is relative to the computational domain. Note that we
        # are deliberately dropping the intervals ordering (by turning `intervals`
        # into a list), as this is irrelevant (even more: dangerous) for data spaces
        intervals = [i if i.dim in oobs else i.zero() for i in intervals]
        intervals += [Interval(i, 0, 0) for i in ordering
                      if i not in ispace.dimensions + conditionals]
        parts = {k: IntervalGroup(build_intervals(v)) for k, v in mapper.items() if k}
        dspace = DataSpace(intervals, parts)

        # Finally create the LoweredEq with all metadata attached
        expr = super(LoweredEq, cls).__new__(cls, expr.lhs, expr.rhs, evaluate=False)

        expr._dspace = dspace
        expr._ispace = ispace
        expr._conditionals = tuple(conditionals)
        expr._reads, expr._writes = detect_io(expr)

        expr._is_Increment = input_expr.is_Increment
        expr._implicit_dims = input_expr.implicit_dims

        return expr
Esempio n. 2
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    def __new__(cls, *args, **kwargs):
        if len(args) == 1 and isinstance(args[0], LoweredEq):
            # origin: LoweredEq(devito.LoweredEq, **kwargs)
            input_expr = args[0]
            expr = Eq.__new__(cls, *input_expr.args, evaluate=False)
            for i in cls._state:
                setattr(expr, '_%s' % i, kwargs.get(i) or getattr(input_expr, i))
            return expr
        elif len(args) == 1 and isinstance(args[0], Eq):
            # origin: LoweredEq(sympy.Eq)
            input_expr = expr = args[0]
        elif len(args) == 2:
            expr = Eq.__new__(cls, *args, evaluate=False)
            for i in cls._state:
                setattr(expr, '_%s' % i, kwargs.pop(i))
            return expr
        else:
            raise ValueError("Cannot construct LoweredEq from args=%s "
                             "and kwargs=%s" % (str(args), str(kwargs)))

        # Well-defined dimension ordering
        ordering = dimension_sort(expr)

        # Analyze the expression
        mapper = detect_accesses(expr)
        oobs = detect_oobs(mapper)
        conditionals = [i for i in ordering if i.is_Conditional]

        # The iteration space is constructed so that information always flows
        # from an iteration to another (i.e., no anti-dependences are created)
        directions, _ = force_directions(detect_flow_directions(expr), lambda i: Any)
        iterators = build_iterators(mapper)
        intervals = build_intervals(Stencil.union(*mapper.values()))
        intervals = IntervalGroup(intervals, relations=ordering.relations)
        ispace = IterationSpace(intervals.zero(), iterators, directions)

        # The data space is relative to the computational domain. Note that we
        # are deliberately dropping the intervals ordering (by turning `intervals`
        # into a list), as this is irrelevant (even more: dangerous) for data spaces
        intervals = [i if i.dim in oobs else i.zero() for i in intervals]
        intervals += [Interval(i, 0, 0) for i in ordering
                      if i not in ispace.dimensions + conditionals]
        parts = {k: IntervalGroup(build_intervals(v)) for k, v in mapper.items() if k}
        dspace = DataSpace(intervals, parts)

        # Finally create the LoweredEq with all metadata attached
        expr = super(LoweredEq, cls).__new__(cls, expr.lhs, expr.rhs, evaluate=False)
        expr._is_Increment = getattr(input_expr, 'is_Increment', False)
        expr._dspace = dspace
        expr._ispace = ispace
        expr._conditionals = tuple(conditionals)
        expr._reads, expr._writes = detect_io(expr)

        return expr
Esempio n. 3
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    def dspace(self):
        """
        Derive the DataSpace of the Cluster from its expressions, IterationSpace,
        and Guards.
        """
        accesses = detect_accesses(self.exprs)

        # Construct the `parts` of the DataSpace, that is a projection of the data
        # space for each Function appearing in `self.exprs`
        parts = {}
        for f, v in accesses.items():
            if f is None:
                continue

            intervals = [
                Interval(d, min(offs), max(offs)) for d, offs in v.items()
            ]
            intervals = IntervalGroup(intervals)

            # Factor in the IterationSpace -- if the min/max points aren't zero,
            # then the data intervals need to shrink/expand accordingly
            intervals = intervals.promote(lambda d: d.is_Block)
            shift = self.ispace.intervals.promote(lambda d: d.is_Block)
            intervals = intervals.add(shift)

            # Map SubIterators to the corresponding data space Dimension
            # E.g., `xs -> x -> x0_blk0 -> x` or `t0 -> t -> time`
            intervals = intervals.promote(lambda d: d.is_SubIterator)

            # If the bound of a Dimension is explicitly guarded, then we should
            # shrink the `parts` accordingly
            for d, v in self.guards.items():
                ret = v.find(BaseGuardBoundNext)
                assert len(ret) <= 1
                if len(ret) != 1:
                    continue
                if ret.pop().direction is Forward:
                    intervals = intervals.translate(d, v1=-1)
                else:
                    intervals = intervals.translate(d, 1)

            # Special case: if the factor of a ConditionalDimension has value 1,
            # then we can safely resort to the parent's Interval
            intervals = intervals.promote(
                lambda d: d.is_Conditional and d.factor == 1)

            parts[f] = intervals

        # Determine the Dimensions requiring shifted min/max points to avoid
        # OOB accesses
        oobs = set()
        for f, v in parts.items():
            for i in v:
                if i.dim.is_Sub:
                    d = i.dim.parent
                else:
                    d = i.dim
                try:
                    if i.lower < 0 or \
                       i.upper > f._size_nodomain[d].left + f._size_halo[d].right:
                        # It'd mean trying to access a point before the
                        # left halo (test0) or after the right halo (test1)
                        oobs.update(d._defines)
                except (KeyError, TypeError):
                    # Unable to detect presence of OOB accesses (e.g., `d` not in
                    # `f._size_halo`, that is typical of indirect accesses `A[B[i]]`)
                    pass

        # Construct the `intervals` of the DataSpace, that is a global,
        # Dimension-centric view of the data space
        intervals = IntervalGroup.generate('union', *parts.values())
        # E.g., `db0 -> time`, but `xi NOT-> x`
        intervals = intervals.promote(lambda d: not d.is_Sub)
        intervals = intervals.zero(set(intervals.dimensions) - oobs)

        return DataSpace(intervals, parts)