transformations.py 47.7 KB
Newer Older
1
import warnings
2
from collections import defaultdict, OrderedDict, namedtuple
3
from copy import deepcopy
Martin Bauer's avatar
Martin Bauer committed
4
from types import MappingProxyType
5

6
7
import sympy as sp
from sympy.logic.boolalg import Boolean
8
from sympy.tensor import IndexedBase
9
from pystencils.assignment import Assignment
10
from pystencils.assignment_collection.nestedscopes import NestedScopes
Martin Bauer's avatar
Martin Bauer committed
11
from pystencils.field import Field, FieldType
Martin Bauer's avatar
Martin Bauer committed
12
from pystencils.data_types import TypedSymbol, PointerType, StructType, get_base_type, cast_func, \
13
    pointer_arithmetic_func, get_type_of_expression, collate_types, create_type
Martin Bauer's avatar
Martin Bauer committed
14
from pystencils.slicing import normalize_slice
Martin Bauer's avatar
Martin Bauer committed
15
import pystencils.astnodes as ast
16
17


Martin Bauer's avatar
Martin Bauer committed
18
def filtered_tree_iteration(node, node_type, stop_type=None):
19
    for arg in node.args:
Martin Bauer's avatar
Martin Bauer committed
20
        if isinstance(arg, node_type):
21
            yield arg
Martin Bauer's avatar
Martin Bauer committed
22
23
24
        elif stop_type and isinstance(node, stop_type):
            continue

Martin Bauer's avatar
Martin Bauer committed
25
        yield from filtered_tree_iteration(arg, node_type)
26
27


28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
def unify_shape_symbols(body, common_shape, fields):
    """Replaces symbols for array sizes to ensure they are represented by the same unique symbol.

    When creating a kernel with variable array sizes, all passed arrays must have the same size.
    This is ensured when the kernel is called. Inside the kernel this means that only on symbol has to be used instead
    of one for each field. For example shape_arr1[0]  and shape_arr2[0] must be equal, so they should also be
    represented by the same symbol.

    Args:
        body: ast node, for the kernel part where substitutions is made, is modified in-place
        common_shape: shape of the field that was chosen
        fields: all fields whose shapes should be replaced by common_shape
    """
    substitutions = {}
    for field in fields:
        assert len(field.spatial_shape) == len(common_shape)
        if not field.has_fixed_shape:
            for common_shape_component, shape_component in zip(common_shape, field.spatial_shape):
                if shape_component != common_shape_component:
                    substitutions[shape_component] = common_shape_component
    if substitutions:
        body.subs(substitutions)


Martin Bauer's avatar
Martin Bauer committed
52
def get_common_shape(field_set):
53
54
    """Takes a set of pystencils Fields and returns their common spatial shape if it exists. Otherwise
    ValueError is raised"""
Martin Bauer's avatar
Martin Bauer committed
55
56
57
58
59
60
61
62
    nr_of_fixed_shaped_fields = 0
    for f in field_set:
        if f.has_fixed_shape:
            nr_of_fixed_shaped_fields += 1

    if nr_of_fixed_shaped_fields > 0 and nr_of_fixed_shaped_fields != len(field_set):
        fixed_field_names = ",".join([f.name for f in field_set if f.has_fixed_shape])
        var_field_names = ",".join([f.name for f in field_set if not f.has_fixed_shape])
63
        msg = "Mixing fixed-shaped and variable-shape fields in a single kernel is not possible\n"
Martin Bauer's avatar
Martin Bauer committed
64
        msg += "Variable shaped: %s \nFixed shaped:    %s" % (var_field_names, fixed_field_names)
65
66
        raise ValueError(msg)

Martin Bauer's avatar
Martin Bauer committed
67
68
69
70
    shape_set = set([f.spatial_shape for f in field_set])
    if nr_of_fixed_shaped_fields == len(field_set):
        if len(shape_set) != 1:
            raise ValueError("Differently sized field accesses in loop body: " + str(shape_set))
71

Martin Bauer's avatar
Martin Bauer committed
72
    shape = list(sorted(shape_set, key=lambda e: str(e[0])))[0]
73
74
75
    return shape


76
77
78
79
80
81
82
83
84
85
86
87
88
89
def get_field_accesses(expr, result=set()):
    if isinstance(expr, Field.Access):
        result.add(expr)
        for o in expr.offsets:
            get_field_accesses(o, result)
        for i in expr.index:
            get_field_accesses(i, result)
    elif hasattr(expr, 'atoms'):
        new_accesses = expr.atoms(Field.Access)
        result.update(new_accesses)
        for a in new_accesses:
            get_field_accesses(a, result)


Martin Bauer's avatar
Martin Bauer committed
90
91
92
93
def make_loop_over_domain(body, function_name, iteration_slice=None, ghost_layers=None, loop_order=None):
    """Uses :class:`pystencils.field.Field.Access` to create (multiple) loops around given AST.

    Args:
94
        body: Block object with inner loop contents
Martin Bauer's avatar
Martin Bauer committed
95
96
97
98
99
100
101
102
103
        function_name: name of generated C function
        iteration_slice: if not None, iteration is done only over this slice of the field
        ghost_layers: a sequence of pairs for each coordinate with lower and upper nr of ghost layers
             if None, the number of ghost layers is determined automatically and assumed to be equal for a
             all dimensions
        loop_order: loop ordering from outer to inner loop (optimal ordering is same as layout)

    Returns:
        :class:`LoopOverCoordinate` instance with nested loops, ordered according to field layouts
104
105
    """
    # find correct ordering by inspecting participating FieldAccesses
106
107
108
109
    field_accesses = set()
    get_field_accesses(body, field_accesses)
    field_accesses = {e for e in field_accesses if not e.is_absolute_access}

Martin Bauer's avatar
Martin Bauer committed
110
111
112
113
114
115
116
117
    # exclude accesses to buffers from field_list, because buffers are treated separately
    field_list = [e.field for e in field_accesses if not FieldType.is_buffer(e.field)]
    fields = set(field_list)
    num_buffer_accesses = len(field_accesses) - len(field_list)

    if loop_order is None:
        loop_order = get_optimal_loop_ordering(fields)

118
119
    shape = get_common_shape(fields)
    unify_shape_symbols(body, common_shape=shape, fields=fields)
Martin Bauer's avatar
Martin Bauer committed
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

    if iteration_slice is not None:
        iteration_slice = normalize_slice(iteration_slice, shape)

    if ghost_layers is None:
        required_ghost_layers = max([fa.required_ghost_layers for fa in field_accesses])
        ghost_layers = [(required_ghost_layers, required_ghost_layers)] * len(loop_order)
    if isinstance(ghost_layers, int):
        ghost_layers = [(ghost_layers, ghost_layers)] * len(loop_order)

    def get_loop_stride(loop_begin, loop_end, step):
        return (loop_end - loop_begin) / step

    loop_strides = []
    loop_vars = []
    current_body = body
Martin Bauer's avatar
Martin Bauer committed
136
    for i, loop_coordinate in enumerate(reversed(loop_order)):
Martin Bauer's avatar
Martin Bauer committed
137
        if iteration_slice is None:
Martin Bauer's avatar
Martin Bauer committed
138
139
140
            begin = ghost_layers[loop_coordinate][0]
            end = shape[loop_coordinate] - ghost_layers[loop_coordinate][1]
            new_loop = ast.LoopOverCoordinate(current_body, loop_coordinate, begin, end, 1)
Martin Bauer's avatar
Martin Bauer committed
141
142
143
            current_body = ast.Block([new_loop])
            loop_strides.append(get_loop_stride(begin, end, 1))
            loop_vars.append(new_loop.loop_counter_symbol)
Martin Bauer's avatar
Martin Bauer committed
144
        else:
Martin Bauer's avatar
Martin Bauer committed
145
            slice_component = iteration_slice[loop_coordinate]
Martin Bauer's avatar
Martin Bauer committed
146
147
            if type(slice_component) is slice:
                sc = slice_component
Martin Bauer's avatar
Martin Bauer committed
148
                new_loop = ast.LoopOverCoordinate(current_body, loop_coordinate, sc.start, sc.stop, sc.step)
Martin Bauer's avatar
Martin Bauer committed
149
150
151
                current_body = ast.Block([new_loop])
                loop_strides.append(get_loop_stride(sc.start, sc.stop, sc.step))
                loop_vars.append(new_loop.loop_counter_symbol)
Martin Bauer's avatar
Martin Bauer committed
152
            else:
Martin Bauer's avatar
Martin Bauer committed
153
                assignment = ast.SympyAssignment(ast.LoopOverCoordinate.get_loop_counter_symbol(loop_coordinate),
Martin Bauer's avatar
Martin Bauer committed
154
155
                                                 sp.sympify(slice_component))
                current_body.insert_front(assignment)
156

Martin Bauer's avatar
Martin Bauer committed
157
158
159
    loop_vars = [num_buffer_accesses * var for var in loop_vars]
    ast_node = ast.KernelFunction(current_body, ghost_layers=ghost_layers, function_name=function_name, backend='cpu')
    return ast_node, loop_strides, loop_vars
160
161


Martin Bauer's avatar
Martin Bauer committed
162
def create_intermediate_base_pointer(field_access, coordinates, previous_ptr):
Martin Bauer's avatar
Martin Bauer committed
163
    r"""
164
    Addressing elements in structured arrays is done with :math:`ptr\left[ \sum_i c_i \cdot s_i \right]`
Martin Bauer's avatar
Martin Bauer committed
165
166
167
168
169
    where :math:`c_i` is the coordinate value and :math:`s_i` the stride of a coordinate.
    The sum can be split up into multiple parts, such that parts of it can be pulled before loops.
    This function creates such an access for coordinates :math:`i \in \mbox{coordinates}`.
    Returns a new typed symbol, where the name encodes which coordinates have been resolved.

170
171
172
173
174
175
176
177
178
    Args:
        field_access: instance of :class:`pystencils.field.Field.Access` which provides strides and offsets
        coordinates: mapping of coordinate ids to its value, where stride*value is calculated
        previous_ptr: the pointer which is de-referenced

    Returns
        tuple with the new pointer symbol and the calculated offset

    Examples:
Martin Bauer's avatar
Martin Bauer committed
179
        >>> field = Field.create_generic('myfield', spatial_dimensions=2, index_dimensions=1)
Martin Bauer's avatar
Martin Bauer committed
180
        >>> x, y = sp.symbols("x y")
Martin Bauer's avatar
Martin Bauer committed
181
182
        >>> prev_pointer = TypedSymbol("ptr", "double")
        >>> create_intermediate_base_pointer(field[1,-2](5), {0: x}, prev_pointer)
Martin Bauer's avatar
Martin Bauer committed
183
        (ptr_01, x*fstride_myfield[0] + fstride_myfield[0])
Martin Bauer's avatar
Martin Bauer committed
184
        >>> create_intermediate_base_pointer(field[1,-2](5), {0: x, 1 : y }, prev_pointer)
Martin Bauer's avatar
Martin Bauer committed
185
        (ptr_01_1m2, x*fstride_myfield[0] + y*fstride_myfield[1] + fstride_myfield[0] - 2*fstride_myfield[1])
Martin Bauer's avatar
Martin Bauer committed
186
    """
Martin Bauer's avatar
Martin Bauer committed
187
    field = field_access.field
188
189
    offset = 0
    name = ""
Martin Bauer's avatar
Martin Bauer committed
190
    list_to_hash = []
Martin Bauer's avatar
Martin Bauer committed
191
192
    for coordinate_id, coordinate_value in coordinates.items():
        offset += field.strides[coordinate_id] * coordinate_value
193

Martin Bauer's avatar
Martin Bauer committed
194
195
196
        if coordinate_id < field.spatial_dimensions:
            offset += field.strides[coordinate_id] * field_access.offsets[coordinate_id]
            if type(field_access.offsets[coordinate_id]) is int:
Martin Bauer's avatar
Martin Bauer committed
197
                name += "_%d%d" % (coordinate_id, field_access.offsets[coordinate_id])
198
            else:
Martin Bauer's avatar
Martin Bauer committed
199
                list_to_hash.append(field_access.offsets[coordinate_id])
200
        else:
Martin Bauer's avatar
Martin Bauer committed
201
            if type(coordinate_value) is int:
Martin Bauer's avatar
Martin Bauer committed
202
                name += "_%d%d" % (coordinate_id, coordinate_value)
203
            else:
Martin Bauer's avatar
Martin Bauer committed
204
                list_to_hash.append(coordinate_value)
205

Martin Bauer's avatar
Martin Bauer committed
206
    if len(list_to_hash) > 0:
Martin Bauer's avatar
Martin Bauer committed
207
        name += "_%0.6X" % (hash(tuple(list_to_hash)))
208

Martin Bauer's avatar
Martin Bauer committed
209
    name = name.replace("-", 'm')
Martin Bauer's avatar
Martin Bauer committed
210
211
    new_ptr = TypedSymbol(previous_ptr.name + name, previous_ptr.dtype)
    return new_ptr, offset
212
213


Martin Bauer's avatar
Martin Bauer committed
214
def parse_base_pointer_info(base_pointer_specification, loop_order, spatial_dimensions, index_dimensions):
215
    """
Martin Bauer's avatar
Martin Bauer committed
216
    Creates base pointer specification for :func:`resolve_field_accesses` function.
Martin Bauer's avatar
Martin Bauer committed
217
218
219

    Specification of how many and which intermediate pointers are created for a field access.
    For example [ (0), (2,3,)]  creates on base pointer for coordinates 2 and 3 and writes the offset for coordinate
220
    zero directly in the field access. These specifications are defined dependent on the loop ordering.
Martin Bauer's avatar
Martin Bauer committed
221
222
    This function translates more readable version into the specification above.

223
    Allowed specifications:
Martin Bauer's avatar
Martin Bauer committed
224
225
226
227
228
229
        - "spatialInner<int>" spatialInner0 is the innermost loop coordinate,
          spatialInner1 the loop enclosing the innermost
        - "spatialOuter<int>" spatialOuter0 is the outermost loop
        - "index<int>": index coordinate
        - "<int>": specifying directly the coordinate

Martin Bauer's avatar
Martin Bauer committed
230
231
232
    Args:
        base_pointer_specification: nested list with above specifications
        loop_order: list with ordering of loops from outer to inner
Martin Bauer's avatar
Martin Bauer committed
233
234
        spatial_dimensions: number of spatial dimensions
        index_dimensions: number of index dimensions
Martin Bauer's avatar
Martin Bauer committed
235
236
237

    Returns:
        list of tuples that can be passed to :func:`resolve_field_accesses`
Martin Bauer's avatar
Martin Bauer committed
238
239
240
241
242

    Examples:
        >>> parse_base_pointer_info([['spatialOuter0'], ['index0']], loop_order=[2,1,0],
        ...                         spatial_dimensions=3, index_dimensions=1)
        [[0], [3], [1, 2]]
243
244
    """
    result = []
Martin Bauer's avatar
Martin Bauer committed
245
246
    specified_coordinates = set()
    loop_order = list(reversed(loop_order))
Martin Bauer's avatar
Martin Bauer committed
247
    for spec_group in base_pointer_specification:
Martin Bauer's avatar
Martin Bauer committed
248
249
250
        new_group = []

        def add_new_element(elem):
Martin Bauer's avatar
Martin Bauer committed
251
            if elem >= spatial_dimensions + index_dimensions:
Martin Bauer's avatar
Martin Bauer committed
252
253
254
255
256
                raise ValueError("Coordinate %d does not exist" % (elem,))
            new_group.append(elem)
            if elem in specified_coordinates:
                raise ValueError("Coordinate %d specified two times" % (elem,))
            specified_coordinates.add(elem)
Martin Bauer's avatar
Martin Bauer committed
257
        for element in spec_group:
258
            if type(element) is int:
Martin Bauer's avatar
Martin Bauer committed
259
                add_new_element(element)
260
261
262
263
            elif element.startswith("spatial"):
                element = element[len("spatial"):]
                if element.startswith("Inner"):
                    index = int(element[len("Inner"):])
Martin Bauer's avatar
Martin Bauer committed
264
                    add_new_element(loop_order[index])
265
266
                elif element.startswith("Outer"):
                    index = int(element[len("Outer"):])
Martin Bauer's avatar
Martin Bauer committed
267
                    add_new_element(loop_order[-index])
268
                elif element == "all":
Martin Bauer's avatar
Martin Bauer committed
269
                    for i in range(spatial_dimensions):
Martin Bauer's avatar
Martin Bauer committed
270
                        add_new_element(i)
271
272
273
274
                else:
                    raise ValueError("Could not parse " + element)
            elif element.startswith("index"):
                index = int(element[len("index"):])
Martin Bauer's avatar
Martin Bauer committed
275
                add_new_element(spatial_dimensions + index)
276
277
278
            else:
                raise ValueError("Unknown specification %s" % (element,))

Martin Bauer's avatar
Martin Bauer committed
279
        result.append(new_group)
280

Martin Bauer's avatar
Martin Bauer committed
281
    all_coordinates = set(range(spatial_dimensions + index_dimensions))
Martin Bauer's avatar
Martin Bauer committed
282
    rest = all_coordinates - specified_coordinates
283
284
    if rest:
        result.append(list(rest))
285

286
287
288
    return result


Martin Bauer's avatar
Martin Bauer committed
289
290
def substitute_array_accesses_with_constants(ast_node):
    """Substitutes all instances of Indexed (array accesses) that are not field accesses with constants.
Martin Bauer's avatar
Martin Bauer committed
291
292
293
    Benchmarks showed that using an array access as loop bound or in pointer computations cause some compilers to do
    less optimizations.
    This transformation should be after field accesses have been resolved (since they introduce array accesses) and
294
295
296
    before constants are moved before the loops.
    """

Martin Bauer's avatar
Martin Bauer committed
297
    def handle_sympy_expression(expr, parent_block):
298
299
300
301
302
303
        """Returns sympy expression where array accesses have been replaced with constants, together with a list
        of assignments that define these constants"""
        if not isinstance(expr, sp.Expr):
            return expr

        # get all indexed expressions that are not field accesses
Martin Bauer's avatar
Martin Bauer committed
304
        indexed_expressions = [e for e in expr.atoms(sp.Indexed) if not isinstance(e, ast.ResolvedFieldAccess)]
305
306
        if len(indexed_expressions) == 0:
            return expr
307
308

        # special case: right hand side is a single indexed expression, then nothing has to be done
Martin Bauer's avatar
Martin Bauer committed
309
        if len(indexed_expressions) == 1 and expr == indexed_expressions[0]:
310
311
            return expr

Martin Bauer's avatar
Martin Bauer committed
312
313
        constants_definitions = []
        constant_substitutions = {}
Martin Bauer's avatar
Martin Bauer committed
314
315
        for indexed_expr in indexed_expressions:
            base, idx = indexed_expr.args
Martin Bauer's avatar
Martin Bauer committed
316
317
318
319
            typed_symbol = base.args[0]
            base_type = deepcopy(get_base_type(typed_symbol.dtype))
            base_type.const = False
            constant_replacing_indexed = TypedSymbol(typed_symbol.name + str(idx), base_type)
Martin Bauer's avatar
Martin Bauer committed
320
321
            constants_definitions.append(ast.SympyAssignment(constant_replacing_indexed, indexed_expr))
            constant_substitutions[indexed_expr] = constant_replacing_indexed
Martin Bauer's avatar
Martin Bauer committed
322
323
324
        constants_definitions.sort(key=lambda e: e.lhs.name)

        already_defined = parent_block.symbols_defined
Martin Bauer's avatar
Martin Bauer committed
325
326
327
        for new_assignment in constants_definitions:
            if new_assignment.lhs not in already_defined:
                parent_block.insert_before(new_assignment, ast_node)
Martin Bauer's avatar
Martin Bauer committed
328
329
330
331
332
333
334
335
336
337
338

        return expr.subs(constant_substitutions)

    if isinstance(ast_node, ast.SympyAssignment):
        ast_node.rhs = handle_sympy_expression(ast_node.rhs, ast_node.parent)
        ast_node.lhs = handle_sympy_expression(ast_node.lhs, ast_node.parent)
    elif isinstance(ast_node, ast.LoopOverCoordinate):
        ast_node.start = handle_sympy_expression(ast_node.start, ast_node.parent)
        ast_node.stop = handle_sympy_expression(ast_node.stop, ast_node.parent)
        ast_node.step = handle_sympy_expression(ast_node.step, ast_node.parent)
        substitute_array_accesses_with_constants(ast_node.body)
339
    else:
Martin Bauer's avatar
Martin Bauer committed
340
341
        for a in ast_node.args:
            substitute_array_accesses_with_constants(a)
342

Martin Bauer's avatar
Martin Bauer committed
343

Martin Bauer's avatar
Martin Bauer committed
344
345
def resolve_buffer_accesses(ast_node, base_buffer_index, read_only_field_names=set()):
    def visit_sympy_expr(expr, enclosing_block, sympy_assignment):
346
        if isinstance(expr, Field.Access):
Martin Bauer's avatar
Martin Bauer committed
347
            field_access = expr
348
349

            # Do not apply transformation if field is not a buffer
Martin Bauer's avatar
Martin Bauer committed
350
            if not FieldType.is_buffer(field_access.field):
351
352
                return expr

Martin Bauer's avatar
Martin Bauer committed
353
            buffer = field_access.field
354

355
            dtype = PointerType(buffer.dtype, const=buffer.name in read_only_field_names, restrict=False)
Martin Bauer's avatar
Martin Bauer committed
356
            field_ptr = TypedSymbol("%s%s" % (Field.DATA_PREFIX, symbol_name_to_variable_name(buffer.name)), dtype)
357

Martin Bauer's avatar
Martin Bauer committed
358
359
            buffer_index = base_buffer_index
            if len(field_access.index) > 1:
360
361
                raise RuntimeError('Only indexing dimensions up to 1 are currently supported in buffers!')

Martin Bauer's avatar
Martin Bauer committed
362
363
364
            if len(field_access.index) > 0:
                cell_index = field_access.index[0]
                buffer_index += cell_index
365

Martin Bauer's avatar
Martin Bauer committed
366
367
            result = ast.ResolvedFieldAccess(field_ptr, buffer_index, field_access.field, field_access.offsets,
                                             field_access.index)
368

Martin Bauer's avatar
Martin Bauer committed
369
            return visit_sympy_expr(result, enclosing_block, sympy_assignment)
370
371
372
373
        else:
            if isinstance(expr, ast.ResolvedFieldAccess):
                return expr

Martin Bauer's avatar
Martin Bauer committed
374
            new_args = [visit_sympy_expr(e, enclosing_block, sympy_assignment) for e in expr.args]
375
            kwargs = {'evaluate': False} if type(expr) in (sp.Add, sp.Mul, sp.Piecewise) else {}
Martin Bauer's avatar
Martin Bauer committed
376
377
378
379
380
381
382
383
            return expr.func(*new_args, **kwargs) if new_args else expr

    def visit_node(sub_ast):
        if isinstance(sub_ast, ast.SympyAssignment):
            enclosing_block = sub_ast.parent
            assert type(enclosing_block) is ast.Block
            sub_ast.lhs = visit_sympy_expr(sub_ast.lhs, enclosing_block, sub_ast)
            sub_ast.rhs = visit_sympy_expr(sub_ast.rhs, enclosing_block, sub_ast)
384
        else:
Martin Bauer's avatar
Martin Bauer committed
385
386
            for i, a in enumerate(sub_ast.args):
                visit_node(a)
387

Martin Bauer's avatar
Martin Bauer committed
388
    return visit_node(ast_node)
389

390

Martin Bauer's avatar
Martin Bauer committed
391
def resolve_field_accesses(ast_node, read_only_field_names=set(),
Martin Bauer's avatar
Martin Bauer committed
392
393
                           field_to_base_pointer_info=MappingProxyType({}),
                           field_to_fixed_coordinates=MappingProxyType({})):
Martin Bauer's avatar
Martin Bauer committed
394
395
396
    """
    Substitutes :class:`pystencils.field.Field.Access` nodes by array indexing

397
398
399
400
401
402
    Args:
        ast_node: the AST root
        read_only_field_names: set of field names which are considered read-only
        field_to_base_pointer_info: a list of tuples indicating which intermediate base pointers should be created
                                    for details see :func:`parse_base_pointer_info`
        field_to_fixed_coordinates: map of field name to a tuple of coordinate symbols. Instead of using the loop
Martin Bauer's avatar
Martin Bauer committed
403
                                    counters to index the field these symbols are used as coordinates
404
405
406

    Returns
        transformed AST
Martin Bauer's avatar
Martin Bauer committed
407
    """
Martin Bauer's avatar
Martin Bauer committed
408
409
    field_to_base_pointer_info = OrderedDict(sorted(field_to_base_pointer_info.items(), key=lambda pair: pair[0]))
    field_to_fixed_coordinates = OrderedDict(sorted(field_to_fixed_coordinates.items(), key=lambda pair: pair[0]))
410

Martin Bauer's avatar
Martin Bauer committed
411
    def visit_sympy_expr(expr, enclosing_block, sympy_assignment):
412
        if isinstance(expr, Field.Access):
Martin Bauer's avatar
Martin Bauer committed
413
            field_access = expr
Martin Bauer's avatar
Martin Bauer committed
414
            field = field_access.field
415

Martin Bauer's avatar
Martin Bauer committed
416
            if field_access.indirect_addressing_fields:
417
418
                new_offsets = tuple(visit_sympy_expr(off, enclosing_block, sympy_assignment)
                                    for off in field_access.offsets)
Martin Bauer's avatar
Martin Bauer committed
419
420
421
422
423
                new_indices = tuple(visit_sympy_expr(ind, enclosing_block, sympy_assignment)
                                    if isinstance(ind, sp.Basic) else ind
                                    for ind in field_access.index)
                field_access = Field.Access(field_access.field, new_offsets,
                                            new_indices, field_access.is_absolute_access)
424

Martin Bauer's avatar
Martin Bauer committed
425
426
            if field.name in field_to_base_pointer_info:
                base_pointer_info = field_to_base_pointer_info[field.name]
427
            else:
Martin Bauer's avatar
Martin Bauer committed
428
                base_pointer_info = [list(range(field.index_dimensions + field.spatial_dimensions))]
429

430
            dtype = PointerType(field.dtype, const=field.name in read_only_field_names, restrict=False)
Martin Bauer's avatar
Martin Bauer committed
431
            field_ptr = TypedSymbol("%s%s" % (Field.DATA_PREFIX, symbol_name_to_variable_name(field.name)), dtype)
432

Martin Bauer's avatar
Martin Bauer committed
433
434
435
436
            def create_coordinate_dict(group_param):
                coordinates = {}
                for e in group_param:
                    if e < field.spatial_dimensions:
Martin Bauer's avatar
Martin Bauer committed
437
                        if field.name in field_to_fixed_coordinates:
438
439
440
441
                            if not field_access.is_absolute_access:
                                coordinates[e] = field_to_fixed_coordinates[field.name][e]
                            else:
                                coordinates[e] = 0
442
                        else:
Martin Bauer's avatar
Martin Bauer committed
443
444
445
446
                            if not field_access.is_absolute_access:
                                coordinates[e] = ast.LoopOverCoordinate.get_loop_counter_symbol(e)
                            else:
                                coordinates[e] = 0
Martin Bauer's avatar
Martin Bauer committed
447
                        coordinates[e] *= field.dtype.item_size
448
                    else:
449
                        if isinstance(field.dtype, StructType):
Martin Bauer's avatar
Martin Bauer committed
450
                            assert field.index_dimensions == 1
Martin Bauer's avatar
Martin Bauer committed
451
452
                            accessed_field_name = field_access.index[0]
                            assert isinstance(accessed_field_name, str)
Martin Bauer's avatar
Martin Bauer committed
453
                            coordinates[e] = field.dtype.get_element_offset(accessed_field_name)
454
                        else:
Martin Bauer's avatar
Martin Bauer committed
455
                            coordinates[e] = field_access.index[e - field.spatial_dimensions]
456

Martin Bauer's avatar
Martin Bauer committed
457
                return coordinates
458

Martin Bauer's avatar
Martin Bauer committed
459
            last_pointer = field_ptr
460

Martin Bauer's avatar
Martin Bauer committed
461
462
            for group in reversed(base_pointer_info[1:]):
                coord_dict = create_coordinate_dict(group)
Martin Bauer's avatar
Martin Bauer committed
463
                new_ptr, offset = create_intermediate_base_pointer(field_access, coord_dict, last_pointer)
Martin Bauer's avatar
Martin Bauer committed
464
465
466
467
                if new_ptr not in enclosing_block.symbols_defined:
                    new_assignment = ast.SympyAssignment(new_ptr, last_pointer + offset, is_const=False)
                    enclosing_block.insert_before(new_assignment, sympy_assignment)
                last_pointer = new_ptr
468

Martin Bauer's avatar
Martin Bauer committed
469
            coord_dict = create_coordinate_dict(base_pointer_info[0])
Martin Bauer's avatar
Martin Bauer committed
470
            _, offset = create_intermediate_base_pointer(field_access, coord_dict, last_pointer)
Martin Bauer's avatar
Martin Bauer committed
471
472
            result = ast.ResolvedFieldAccess(last_pointer, offset, field_access.field,
                                             field_access.offsets, field_access.index)
473

Martin Bauer's avatar
Martin Bauer committed
474
475
            if isinstance(get_base_type(field_access.field.dtype), StructType):
                new_type = field_access.field.dtype.get_element_type(field_access.index[0])
Martin Bauer's avatar
Martin Bauer committed
476
                result = cast_func(result, new_type)
477

Martin Bauer's avatar
Martin Bauer committed
478
            return visit_sympy_expr(result, enclosing_block, sympy_assignment)
479
        else:
Martin Bauer's avatar
Martin Bauer committed
480
481
            if isinstance(expr, ast.ResolvedFieldAccess):
                return expr
482

Martin Bauer's avatar
Martin Bauer committed
483
            new_args = [visit_sympy_expr(e, enclosing_block, sympy_assignment) for e in expr.args]
484
            kwargs = {'evaluate': False} if type(expr) in (sp.Add, sp.Mul, sp.Piecewise) else {}
Martin Bauer's avatar
Martin Bauer committed
485
486
487
488
489
490
491
492
            return expr.func(*new_args, **kwargs) if new_args else expr

    def visit_node(sub_ast):
        if isinstance(sub_ast, ast.SympyAssignment):
            enclosing_block = sub_ast.parent
            assert type(enclosing_block) is ast.Block
            sub_ast.lhs = visit_sympy_expr(sub_ast.lhs, enclosing_block, sub_ast)
            sub_ast.rhs = visit_sympy_expr(sub_ast.rhs, enclosing_block, sub_ast)
493
        else:
Martin Bauer's avatar
Martin Bauer committed
494
495
            for i, a in enumerate(sub_ast.args):
                visit_node(a)
496

Martin Bauer's avatar
Martin Bauer committed
497
    return visit_node(ast_node)
498
499


Martin Bauer's avatar
Martin Bauer committed
500
def move_constants_before_loop(ast_node):
501
502
    """Moves :class:`pystencils.ast.SympyAssignment` nodes out of loop body if they are iteration independent.

Martin Bauer's avatar
Martin Bauer committed
503
    Call this after creating the loop structure with :func:`make_loop_over_domain`
Martin Bauer's avatar
Martin Bauer committed
504
    """
Martin Bauer's avatar
Martin Bauer committed
505
    def find_block_to_move_to(node):
Martin Bauer's avatar
Martin Bauer committed
506
507
        """
        Traverses parents of node as long as the symbols are independent and returns a (parent) block
508
        the assignment can be safely moved to
Martin Bauer's avatar
Martin Bauer committed
509
510
511
        :param node: SympyAssignment inside a Block
        :return blockToInsertTo, childOfBlockToInsertBefore
        """
512
513
        assert isinstance(node.parent, ast.Block)

Martin Bauer's avatar
Martin Bauer committed
514
515
        last_block = node.parent
        last_block_child = node
516
        element = node.parent
Martin Bauer's avatar
Martin Bauer committed
517
        prev_element = node
518
519
        while element:
            if isinstance(element, ast.Block):
Martin Bauer's avatar
Martin Bauer committed
520
521
                last_block = element
                last_block_child = prev_element
522
523

            if isinstance(element, ast.Conditional):
Martin Bauer's avatar
Martin Bauer committed
524
                critical_symbols = element.condition_expr.atoms(sp.Symbol)
525
            else:
Martin Bauer's avatar
Martin Bauer committed
526
527
                critical_symbols = element.symbols_defined
            if node.undefined_symbols.intersection(critical_symbols):
528
                break
Martin Bauer's avatar
Martin Bauer committed
529
            prev_element = element
530
            element = element.parent
Martin Bauer's avatar
Martin Bauer committed
531
        return last_block, last_block_child
532

Martin Bauer's avatar
Martin Bauer committed
533
534
    def check_if_assignment_already_in_block(assignment, target_block):
        for arg in target_block.args:
535
536
537
538
539
540
            if type(arg) is not ast.SympyAssignment:
                continue
            if arg.lhs == assignment.lhs:
                return arg
        return None

Martin Bauer's avatar
Martin Bauer committed
541
    def get_blocks(node, result_list):
542
        if isinstance(node, ast.Block):
Martin Bauer's avatar
Martin Bauer committed
543
            result_list.append(node)
544
545
        if isinstance(node, ast.Node):
            for a in node.args:
Martin Bauer's avatar
Martin Bauer committed
546
                get_blocks(a, result_list)
547

Martin Bauer's avatar
Martin Bauer committed
548
549
550
    all_blocks = []
    get_blocks(ast_node, all_blocks)
    for block in all_blocks:
Martin Bauer's avatar
Martin Bauer committed
551
        children = block.take_child_nodes()
552
        for child in children:
553
554
555
            target, child_to_insert_before = find_block_to_move_to(child)
            if target == block:     # movement not possible
                target.append(child)
556
            else:
557
558
                if isinstance(child, ast.SympyAssignment):
                    exists_already = check_if_assignment_already_in_block(child, target)
559
                else:
560
                    exists_already = False
Martin Bauer's avatar
Martin Bauer committed
561

562
563
                if not exists_already:
                    target.insert_before(child, child_to_insert_before)
Martin Bauer's avatar
Martin Bauer committed
564
565
                elif exists_already and exists_already.rhs == child.rhs:
                    pass
566
                else:
Martin Bauer's avatar
Martin Bauer committed
567
                    block.append(child)  # don't move in this case - better would be to rename symbol
568
569


Martin Bauer's avatar
Martin Bauer committed
570
def split_inner_loop(ast_node: ast.Node, symbol_groups):
Martin Bauer's avatar
Martin Bauer committed
571
572
    """
    Splits inner loop into multiple loops to minimize the amount of simultaneous load/store streams
573

Martin Bauer's avatar
Martin Bauer committed
574
575
576
577
578
    Args:
        ast_node: AST root
        symbol_groups: sequence of symbol sequences: for each symbol sequence a new inner loop is created which
                       updates these symbols and their dependent symbols. Symbols which are in none of the symbolGroups
                       and which no symbol in a symbol group depends on, are not updated!
Martin Bauer's avatar
Martin Bauer committed
579
    """
Martin Bauer's avatar
Martin Bauer committed
580
581
582
583
584
585
586
587
588
589
590
591
592
    all_loops = ast_node.atoms(ast.LoopOverCoordinate)
    inner_loop = [l for l in all_loops if l.is_innermost_loop]
    assert len(inner_loop) == 1, "Error in AST: multiple innermost loops. Was split transformation already called?"
    inner_loop = inner_loop[0]
    assert type(inner_loop.body) is ast.Block
    outer_loop = [l for l in all_loops if l.is_outermost_loop]
    assert len(outer_loop) == 1, "Error in AST, multiple outermost loops."
    outer_loop = outer_loop[0]

    symbols_with_temporary_array = OrderedDict()
    assignment_map = OrderedDict((a.lhs, a) for a in inner_loop.body.args)

    assignment_groups = []
Martin Bauer's avatar
Martin Bauer committed
593
    for symbol_group in symbol_groups:
594
        # get all dependent symbols
Martin Bauer's avatar
Martin Bauer committed
595
        symbols_to_process = list(symbol_group)
Martin Bauer's avatar
Martin Bauer committed
596
597
598
599
        symbols_resolved = set()
        while symbols_to_process:
            s = symbols_to_process.pop()
            if s in symbols_resolved:
600
601
                continue

Martin Bauer's avatar
Martin Bauer committed
602
            if s in assignment_map:  # if there is no assignment inside the loop body it is independent already
Martin Bauer's avatar
Martin Bauer committed
603
604
605
                for new_symbol in assignment_map[s].rhs.atoms(sp.Symbol):
                    if type(new_symbol) is not Field.Access and new_symbol not in symbols_with_temporary_array:
                        symbols_to_process.append(new_symbol)
Martin Bauer's avatar
Martin Bauer committed
606
            symbols_resolved.add(s)
607

Martin Bauer's avatar
Martin Bauer committed
608
        for symbol in symbol_group:
609
610
            if type(symbol) is not Field.Access:
                assert type(symbol) is TypedSymbol
Martin Bauer's avatar
Martin Bauer committed
611
612
                new_ts = TypedSymbol(symbol.name, PointerType(symbol.dtype))
                symbols_with_temporary_array[symbol] = IndexedBase(new_ts, shape=(1,))[inner_loop.loop_counter_symbol]
613

Martin Bauer's avatar
Martin Bauer committed
614
615
616
617
        assignment_group = []
        for assignment in inner_loop.body.args:
            if assignment.lhs in symbols_resolved:
                new_rhs = assignment.rhs.subs(symbols_with_temporary_array.items())
Martin Bauer's avatar
Martin Bauer committed
618
                if type(assignment.lhs) is not Field.Access and assignment.lhs in symbol_group:
619
                    assert type(assignment.lhs) is TypedSymbol
Martin Bauer's avatar
Martin Bauer committed
620
621
                    new_ts = TypedSymbol(assignment.lhs.name, PointerType(assignment.lhs.dtype))
                    new_lhs = IndexedBase(new_ts, shape=(1,))[inner_loop.loop_counter_symbol]
622
                else:
Martin Bauer's avatar
Martin Bauer committed
623
624
625
                    new_lhs = assignment.lhs
                assignment_group.append(ast.SympyAssignment(new_lhs, new_rhs))
        assignment_groups.append(assignment_group)
626

Martin Bauer's avatar
Martin Bauer committed
627
628
    new_loops = [inner_loop.new_loop_with_different_body(ast.Block(group)) for group in assignment_groups]
    inner_loop.parent.replace(inner_loop, ast.Block(new_loops))
629

Martin Bauer's avatar
Martin Bauer committed
630
631
    for tmp_array in symbols_with_temporary_array:
        tmp_array_pointer = TypedSymbol(tmp_array.name, PointerType(tmp_array.dtype))
Martin Bauer's avatar
Martin Bauer committed
632
633
634
635
        alloc_node = ast.TemporaryMemoryAllocation(tmp_array_pointer, inner_loop.stop, inner_loop.start)
        free_node = ast.TemporaryMemoryFree(alloc_node)
        outer_loop.parent.insert_front(alloc_node)
        outer_loop.parent.append(free_node)
636
637


Martin Bauer's avatar
Martin Bauer committed
638
def cut_loop(loop_node, cutting_points):
Martin Bauer's avatar
Martin Bauer committed
639
640
641
642
643
644
645
646
647
648
    """Cuts loop at given cutting points.

    One loop is transformed into len(cuttingPoints)+1 new loops that range from
    old_begin to cutting_points[1], ..., cutting_points[-1] to old_end

    Modifies the ast in place

    Returns:
        list of new loop nodes
    """
Martin Bauer's avatar
Martin Bauer committed
649
    if loop_node.step != 1:
650
        raise NotImplementedError("Can only split loops that have a step of 1")
Martin Bauer's avatar
Martin Bauer committed
651
652
653
    new_loops = []
    new_start = loop_node.start
    cutting_points = list(cutting_points) + [loop_node.stop]
Martin Bauer's avatar
Martin Bauer committed
654
655
    for new_end in cutting_points:
        if new_end - new_start == 1:
Martin Bauer's avatar
Martin Bauer committed
656
657
658
            new_body = deepcopy(loop_node.body)
            new_body.subs({loop_node.loop_counter_symbol: new_start})
            new_loops.append(new_body)
Martin Bauer's avatar
Martin Bauer committed
659
660
        elif new_end - new_start == 0:
            pass
661
        else:
Martin Bauer's avatar
Martin Bauer committed
662
663
            new_loop = ast.LoopOverCoordinate(deepcopy(loop_node.body), loop_node.coordinate_to_loop_over,
                                              new_start, new_end, loop_node.step)
Martin Bauer's avatar
Martin Bauer committed
664
            new_loops.append(new_loop)
Martin Bauer's avatar
Martin Bauer committed
665
        new_start = new_end
Martin Bauer's avatar
Martin Bauer committed
666
    loop_node.parent.replace(loop_node, new_loops)
Martin Bauer's avatar
Martin Bauer committed
667
    return new_loops
668
669


670
671
def simplify_conditionals(node: ast.Node, loop_counter_simplification: bool=False) -> None:
    """Removes conditionals that are always true/false.
672
673

    Args:
674
675
676
677
678
679
        node: ast node, all descendants of this node are simplified
        loop_counter_simplification: if enabled, tries to detect if a conditional is always true/false
                                     depending on the surrounding loop. For example if the surrounding loop goes from
                                     x=0 to 10 and the condition is x < 0, it is removed.
                                     This analysis needs the integer set library (ISL) islpy, so it is not done by
                                     default.
680
    """
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
    for conditional in node.atoms(ast.Conditional):
        conditional.condition_expr = sp.simplify(conditional.condition_expr)
        if conditional.condition_expr == sp.true:
            conditional.parent.replace(conditional, [conditional.true_block])
        elif conditional.condition_expr == sp.false:
            conditional.parent.replace(conditional, [conditional.false_block] if conditional.false_block else [])
        elif loop_counter_simplification:
            try:
                # noinspection PyUnresolvedReferences
                from pystencils.integer_set_analysis import simplify_loop_counter_dependent_conditional
                simplify_loop_counter_dependent_conditional(conditional)
            except ImportError:
                warnings.warn("Integer simplifications in conditionals skipped, because ISLpy package not installed")


def cleanup_blocks(node: ast.Node) -> None:
697
698
699
700
701
    """Curly Brace Removal: Removes empty blocks, and replaces blocks with a single child by its child """
    if isinstance(node, ast.SympyAssignment):
        return
    elif isinstance(node, ast.Block):
        for a in list(node.args):
Martin Bauer's avatar
Martin Bauer committed
702
            cleanup_blocks(a)
703
704
705
706
707
        if len(node.args) <= 1 and isinstance(node.parent, ast.Block):
            node.parent.replace(node, node.args)
            return
    else:
        for a in node.args:
Martin Bauer's avatar
Martin Bauer committed
708
            cleanup_blocks(a)
709
710


Martin Bauer's avatar
Martin Bauer committed
711
def symbol_name_to_variable_name(symbol_name):
712
    """Replaces characters which are allowed in sympy symbol names but not in C/C++ variable names"""
Martin Bauer's avatar
Martin Bauer committed
713
    return symbol_name.replace("^", "_")
714
715


716
717
718
719
720
721
722
723
724
725
726
727
class KernelConstraintsCheck:
    """Checks if the input to create_kernel is valid.

    Test the following conditions:

    - SSA Form for pure symbols:
        -  Every pure symbol may occur only once as left-hand-side of an assignment
        -  Every pure symbol that is read, may not be written to later
    - Independence / Parallelization condition:
        - a field that is written may only be read at exact the same spatial position

    (Pure symbols are symbols that are not Field.Accesses)
Martin Bauer's avatar
Martin Bauer committed
728
    """
729
730
731
732
733
    FieldAndIndex = namedtuple('FieldAndIndex', ['field', 'index'])

    def __init__(self, type_for_symbol, check_independence_condition):
        self._type_for_symbol = type_for_symbol

734
        self.scopes = NestedScopes()
735
736
737
738
739
740
741
742
743
744
        self._field_writes = defaultdict(set)
        self.fields_read = set()
        self.check_independence_condition = check_independence_condition

    def process_assignment(self, assignment):
        # for checks it is crucial to process rhs before lhs to catch e.g. a = a + 1
        new_rhs = self.process_expression(assignment.rhs)
        new_lhs = self._process_lhs(assignment.lhs)
        return ast.SympyAssignment(new_lhs, new_rhs)

745
    def process_expression(self, rhs, type_constants=True):
746
747
        self._update_accesses_rhs(rhs)
        if isinstance(rhs, Field.Access):
Martin Bauer's avatar
Martin Bauer committed
748
            self.fields_read.add(rhs.field)
Martin Bauer's avatar
Martin Bauer committed
749
            self.fields_read.update(rhs.indirect_addressing_fields)
750
751
752
753
754
            return rhs
        elif isinstance(rhs, TypedSymbol):
            return rhs
        elif isinstance(rhs, sp.Symbol):
            return TypedSymbol(symbol_name_to_variable_name(rhs.name), self._type_for_symbol[rhs.name])
755
        elif type_constants and isinstance(rhs, sp.Number):
756
757
            return cast_func(rhs, create_type(self._type_for_symbol['_constant']))
        elif isinstance(rhs, sp.Mul):
758
            new_args = [self.process_expression(arg, type_constants) if arg not in (-1, 1) else arg for arg in rhs.args]
759
            return rhs.func(*new_args) if new_args else rhs
760
761
        elif isinstance(rhs, sp.Indexed):
            return rhs
762
763
764
        else:
            if isinstance(rhs, sp.Pow):
                # don't process exponents -> they should remain integers
765
                return sp.Pow(self.process_expression(rhs.args[0], type_constants), rhs.args[1])
766
            else:
767
                new_args = [self.process_expression(arg, type_constants) for arg in rhs.args]
768
                return rhs.func(*new_args) if new_args else rhs
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786

    @property
    def fields_written(self):
        return set(k.field for k, v in self._field_writes.items() if len(v))

    def _process_lhs(self, lhs):
        assert isinstance(lhs, sp.Symbol)
        self._update_accesses_lhs(lhs)
        if not isinstance(lhs, Field.Access) and not isinstance(lhs, TypedSymbol):
            return TypedSymbol(lhs.name, self._type_for_symbol[lhs.name])
        else:
            return lhs

    def _update_accesses_lhs(self, lhs):
        if isinstance(lhs, Field.Access):
            fai = self.FieldAndIndex(lhs.field, lhs.index)
            self._field_writes[fai].add(lhs.offsets)
            if len(self._field_writes[fai]) > 1:
787
                raise ValueError("Field {} is written at two different locations".format(lhs.field.name))
788
        elif isinstance(lhs, sp.Symbol):
789
            if self.scopes.is_defined_locally(lhs):
790
                raise ValueError("Assignments not in SSA form, multiple assignments to {}".format(lhs.name))
791
            if lhs in self.scopes.free_parameters:
792
                raise ValueError("Symbol {} is written, after it has been read".format(lhs.name))
793
            self.scopes.define_symbol(lhs)
794
795
796
797
798
799
800

    def _update_accesses_rhs(self, rhs):
        if isinstance(rhs, Field.Access) and self.check_independence_condition:
            writes = self._field_writes[self.FieldAndIndex(rhs.field, rhs.index)]
            for write_offset in writes:
                assert len(writes) == 1
                if write_offset != rhs.offsets:
801
802
                    raise ValueError("Violation of loop independence condition. Field "
                                     "{} is read at {} and written at {}".format(rhs.field, rhs.offsets, write_offset))
803
804
            self.fields_read.add(rhs.field)
        elif isinstance(rhs, sp.Symbol):
805
            self.scopes.access_symbol(rhs)
806
807
808
809
810


def add_types(eqs, type_for_symbol, check_independence_condition):
    """Traverses AST and replaces every :class:`sympy.Symbol` by a :class:`pystencils.typedsymbol.TypedSymbol`.

Martin Bauer's avatar
Martin Bauer committed
811
812
    Additionally returns sets of all fields which are read/written

813
814
815
816
817
818
819
820
821
    Args:
        eqs: list of equations
        type_for_symbol: dict mapping symbol names to types. Types are strings of C types like 'int' or 'double'
        check_independence_condition: check that loop iterations are independent - this has to be skipped for indexed
                                      kernels

    Returns:
        ``fields_read, fields_written, typed_equations`` set of read fields, set of written fields,
         list of equations where symbols have been replaced by typed symbols
Martin Bauer's avatar
Martin Bauer committed
822
    """
Martin Bauer's avatar
Martin Bauer committed
823
824
    if isinstance(type_for_symbol, str) or not hasattr(type_for_symbol, '__getitem__'):
        type_for_symbol = typing_from_sympy_inspection(eqs, type_for_symbol)
825

826
    check = KernelConstraintsCheck(type_for_symbol, check_independence_condition)
827

Martin Bauer's avatar
Martin Bauer committed
828
829
830
831
    def visit(obj):
        if isinstance(obj, list) or isinstance(obj, tuple):
            return [visit(e) for e in obj]
        if isinstance(obj, sp.Eq) or isinstance(obj, ast.SympyAssignment) or isinstance(obj, Assignment):
832
            return check.process_assignment(obj)
Martin Bauer's avatar
Martin Bauer committed
833
        elif isinstance(obj, ast.Conditional):
834
            check.scopes.push()
Martin Bauer's avatar
Martin Bauer committed
835
            false_block = None if obj.false_block is None else visit(obj.false_block)
836
837
838
839
            result = ast.Conditional(check.process_expression(obj.condition_expr, type_constants=False),
                                     true_block=visit(obj.true_block), false_block=false_block)
            check.scopes.pop()
            return result
Martin Bauer's avatar
Martin Bauer committed
840
        elif isinstance(obj, ast.Block):
841
842
843
844
            check.scopes.push()
            result = ast.Block([visit(e) for e in obj.args])
            check.scopes.pop()
            return result
845
        elif isinstance(obj, ast.Node) and not isinstance(obj, ast.LoopOverCoordinate):
Martin Bauer's avatar
Martin Bauer committed
846
            return obj
847
848
        else:
            raise ValueError("Invalid object in kernel " + str(type(obj)))
849

Martin Bauer's avatar
Martin Bauer committed
850
    typed_equations = visit(eqs)
851

852
    return check.fields_read, check.fields_written, typed_equations
853
854


Martin Bauer's avatar
Martin Bauer committed
855
def insert_casts(node):
856
    """Checks the types and inserts casts and pointer arithmetic where necessary.
Martin Bauer's avatar
Martin Bauer committed
857

858
859
860
861
862
    Args:
        node: the head node of the ast

    Returns:
        modified AST
Martin Bauer's avatar
Martin Bauer committed
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
    """
    def cast(zipped_args_types, target_dtype):
        """
        Adds casts to the arguments if their type differs from the target type
        :param zipped_args_types: a zipped list of args and types
        :param target_dtype: The target data type
        :return: args with possible casts
        """
        casted_args = []
        for argument, data_type in zipped_args_types:
            if data_type.numpy_dtype != target_dtype.numpy_dtype:  # ignoring const
                casted_args.append(cast_func(argument, target_dtype))
            else:
                casted_args.append(argument)
        return casted_args

    def pointer_arithmetic(expr_args):
        """
        Creates a valid pointer arithmetic function
        :param expr_args: Arguments of the add expression
        :return: pointer_arithmetic_func
        """
        pointer = None
        new_args = []
        for arg, data_type in expr_args:
            if data_type.func is PointerType:
                assert pointer is None
                pointer = arg
        for arg, data_type in expr_args:
            if arg != pointer:
                assert data_type.is_int() or data_type.is_uint()
                new_args.append(arg)
        new_args = sp.Add(*new_args) if len(new_args) > 0 else new_args
        return pointer_arithmetic_func(pointer, new_args)

898
    if isinstance(node, sp.AtomicExpr) or isinstance(node, cast_func):
Martin Bauer's avatar
Martin Bauer committed
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
        return node
    args = []
    for arg in node.args:
        args.append(insert_casts(arg))
    # TODO indexed, LoopOverCoordinate
    if node.func in (sp.Add, sp.Mul, sp.Or, sp.And, sp.Pow, sp.Eq, sp.Ne, sp.Lt, sp.Le, sp.Gt, sp.Ge):
        # TODO optimize pow, don't cast integer on double
        types = [get_type_of_expression(arg) for arg in args]
        assert len(types) > 0
        target = collate_types(types)
        zipped = list(zip(args, types))
        if target.func is PointerType:
            assert node.func is sp.Add
            return pointer_arithmetic(zipped)
        else:
            return node.func(*cast(zipped, target))
    elif node.func is ast.SympyAssignment:
        lhs = args[0]
        rhs = args[1]
        target = get_type_of_expression(lhs)
        if target.func is PointerType:
            return node.func(*args)  # TODO fix, not complete
        else:
            return node.func(lhs, *cast([(rhs, get_type_of_expression(rhs))], target))
    elif node.func is ast.ResolvedFieldAccess:
        return node
    elif node.func is ast.Block:
        for old_arg, new_arg in zip(node.args, args):
            node.replace(old_arg, new_arg)
        return node
    elif node.func is ast.LoopOverCoordinate:
        for old_arg, new_arg in zip(node.args, args):
            node.replace(old_arg, new_arg)
        return node
    elif node.func is sp.Piecewise:
        expressions = [expr for (expr, _) in args]
        types = [get_type_of_expression(expr) for expr in expressions]
        target = collate_types(types)
        zipped = list(zip(expressions, types))
        casted_expressions = cast(zipped, target)
        args = [arg.func(*[expr, arg.cond]) for (arg, expr) in zip(args, casted_expressions)]

    return node.func(*args)


944
945
946
947
948
949
950
951
def remove_conditionals_in_staggered_kernel(function_node: ast.KernelFunction) -> None:
    """Removes conditionals of a kernel that iterates over staggered positions by splitting the loops at last element"""

    all_inner_loops = [l for l in function_node.atoms(ast.LoopOverCoordinate) if l.is_innermost_loop]
    assert len(all_inner_loops) == 1, "Transformation works only on kernels with exactly one inner loop"
    inner_loop = all_inner_loops.pop()

    for loop in parents_of_type(inner_loop, ast.LoopOverCoordinate, include_current=True):
952
        cut_loop(loop, [loop.stop - 1])
953

954
    simplify_conditionals(function_node.body, loop_counter_simplification=True)
955
    cleanup_blocks(function_node.body)
Martin Bauer's avatar
Martin Bauer committed
956

957
958
959
960
    move_constants_before_loop(function_node.body)
    cleanup_blocks(function_node.body)


Martin Bauer's avatar
Martin Bauer committed
961
962
963
# --------------------------------------- Helper Functions -------------------------------------------------------------


Martin Bauer's avatar
Martin Bauer committed
964
def typing_from_sympy_inspection(eqs, default_type="double"):
Martin Bauer's avatar
Martin Bauer committed
965
966
967
    """
    Creates a default symbol name to type mapping.
    If a sympy Boolean is assigned to a symbol it is assumed to be 'bool' otherwise the default type, usually ('double')
968
969
970
971
972
973

    Args:
        eqs: list of equations
        default_type: the type for non-boolean symbols
    Returns:
        dictionary, mapping symbol name to type
Martin Bauer's avatar
Martin Bauer committed
974
    """
Martin Bauer's avatar
Martin Bauer committed
975
    result = defaultdict(lambda: default_type)
976
    for eq in eqs:
977
978
        if isinstance(eq, ast.Node):
            continue
979
980
981
        # problematic case here is when rhs is a symbol: then it is impossible to decide here without
        # further information what type the left hand side is - default fallback is the dict value then
        if isinstance(eq.rhs, Boolean) and not isinstance(eq.rhs, sp.Symbol):
982
983
984
985
            result[eq.lhs.name] = "bool"
    return result


Martin Bauer's avatar
Martin Bauer committed
986
def get_next_parent_of_type(node, parent_type):