Accera v1.2 Reference

accera.cast(value, type)

The cast operation converts a value from one acc.ScalarType to another.

Accera performs implicit casting between most types. Therefore, this operation should only be used to override the implicit casting behavior documented in Section 2.

Limitation: casting constants may result in truncation.

Arguments

argument	description	type/default
value	The value to cast
type	The destination type	acc.ScalarType

Returns

The result after casting

Examples

Casting from float32 to int16:

A = acc.Array(role=acc.Role.INPUT, element_type=acc.ScalarType.float32, shape=(10, 20))
B = acc.Array(role=acc.Role.INPUT_OUTPUT, element_type=acc.ScalarType.int16, shape=(10, 20))

nest = acc.Nest(10, 20)
i, j = nest.get_indices()

@nest.iteration_logic:
def _():
    B[i, j] = acc.cast(A[i, j], acc.ScalarType.int16) # explicit cast to int16
    ...

In comparison, casting from int16 to float32 is implicit, which means the cast operation can be omitted:

A = acc.Array(role=acc.Role.INPUT, element_type=acc.ScalarType.int16, shape=(10, 20))
B = acc.Array(role=acc.Role.INPUT_OUTPUT, element_type=acc.ScalarType.float32, shape=(10, 20))

nest = acc.Nest(10, 20)
i, j = nest.get_indices()

@nest.iteration_logic:
def _():
    B[i, j] = A[i, j] # implicit cast to float32
    ...

Casting a constant to int8:

A = acc.Array(role=acc.Role.INPUT_OUTPUT, element_type=acc.ScalarType.int8, shape=(10, 20))

nest = acc.Nest(10, 20)
i, j = nest.get_indices()

@nest.iteration_logic:
def _():
    A[i, j] = acc.cast(10, acc.ScalarType.int8)
    ...

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Last update: 2023-04-17