Symbols, Constants and Arrays

class pystencils.backend.symbols.PsSymbol(name, dtype=None)

A mutable symbol with name and data type.

Do not create objects of this class directly unless you know what you are doing; instead obtain them from a KernelCreationContext through KernelCreationContext.get_symbol. This way, the context can keep track of all symbols used in the translation run, and uniqueness of symbols is ensured.

Parameters:
apply_dtype(dtype)

Apply the given data type to this symbol, raising a TypeError if it conflicts with a previously set data type.

Parameters:

dtype (PsType) –

class pystencils.backend.constants.PsConstant(value, dtype=None)

Type-safe representation of typed numerical constants.

This class models constants in the backend representation of kernels. A constant may be untyped, in which case its value may be any Python object.

If the constant is typed (i.e. its dtype is not None), its data type is used to check the validity of its value and to convert it into the type’s internal representation.

Instances of PsConstant are immutable.

Parameters:

  • value (Any) – The constant’s value

  • dtype (Optional[PsNumericType]) – The constant’s data type, or None if untyped.

interpret_as(dtype)

Interprets this untyped constant with the given data type.

If this constant is already typed, raises an error.

Return type:

PsConstant

Parameters:

dtype (PsNumericType) –

reinterpret_as(dtype)

Reinterprets this constant with the given data type.

Other than interpret_as, this method also works on typed constants.

Return type:

PsConstant

Parameters:

dtype (PsNumericType) –

property dtype: PsNumericType | None

This constant’s data type, or None if it is untyped.

The data type of a constant always has const == True.

get_dtype()

Retrieve this constant’s data type, throwing an exception if the constant is untyped.

Return type:

PsNumericType

class pystencils.backend.literals.PsLiteral(text, dtype)

Representation of literal code.

Instances of this class represent code literals inside the AST. These literals are not to be confused with C literals; the name Literal refers to the fact that the code generator takes them “literally”, printing them as they are.

Each literal has to be annotated with a type, and is considered constant within the scope of a kernel. Instances of PsLiteral are immutable.

Parameters:
class pystencils.backend.arrays.PsLinearizedArray(name, element_type, shape, strides, index_dtype=PsIntegerType(width=64, signed=True, const=False))

Class to model N-dimensional contiguous arrays.

Memory Layout, Shape and Strides

The memory layout of an array is defined by its shape and strides. Both shape and stride entries may either be constants or special variables associated with exactly one array.

Shape and strides may be specified at construction in the following way. For constant entries, their value must be given as an integer. For variable shape entries and strides, the Ellipsis … must be passed instead. Internally, the passed index_dtype will be used to create typed constants (PsConstant) and variables (PsArrayShapeSymbol and PsArrayStrideSymbol) from the passed values.

Parameters:

  • name (str) –

  • element_type (PsType) –

  • shape (Sequence[int | EllipsisType]) –

  • strides (Sequence[int | EllipsisType]) –

  • index_dtype (PsIntegerType) –

property name

The array’s name

property base_pointer: PsArrayBasePointer

The array’s base pointer

property shape: tuple[PsArrayShapeSymbol | PsConstant, ...]

The array’s shape, expressed using PsConstant and PsArrayShapeSymbol

property shape_spec: tuple[ellipsis | int, ...]

The array’s shape, expressed using int and …

property strides: tuple[PsArrayStrideSymbol | PsConstant, ...]

The array’s strides, expressed using PsConstant and PsArrayStrideSymbol

property strides_spec: tuple[ellipsis | int, ...]

The array’s strides, expressed using int and …

class pystencils.backend.arrays.PsArrayAssocSymbol(name, dtype, array)

A variable that is associated to an array.

Instances of this class represent pointers and indexing information bound to a particular array.

Parameters:
class pystencils.backend.arrays.PsArrayBasePointer(name, array)
Parameters:
class pystencils.backend.arrays.TypeErasedBasePointer(name, array)

Base pointer for arrays whose element type has been erased.

Used primarily for arrays of anonymous structs.

Parameters:
class pystencils.backend.arrays.PsArrayShapeSymbol(array, coordinate, dtype)

Variable that represents an array’s shape in one coordinate.

Do not instantiate this class yourself, but only use its instances as provided by PsLinearizedArray.shape.

Parameters:
class pystencils.backend.arrays.PsArrayStrideSymbol(array, coordinate, dtype)

Variable that represents an array’s stride in one coordinate.

Do not instantiate this class yourself, but only use its instances as provided by PsLinearizedArray.strides.

Parameters: