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Python function

declare

declare()

max.experimental.custom.declare(name, *, inputs, outputs, parameters=None, custom_extensions=())

source

Declares a custom op from its signature.

Validates the signature, compiles any Mojo source package, and resolves the kernel against custom_extensions once, here, rather than on every call.

Parameters:

• name (str) – The registered kernel symbol.
• inputs (Mapping[str, TemplateType]) – One TemplateType per operand, keyed by a name used in diagnostics and accepted as a keyword at call time. Iteration order is operand order.
• outputs (Sequence[TemplateType]) – One TemplateType per result. Dims may only be statics, Symbol and Param values, or expressions over them. A Symbol no input binds is data-dependent: the kernel must register a shape function with @extensibility.register_shape_function (see the “Declare the output shape” section of https://docs.modular.com/max/develop/build-custom-ops).
• parameters (Mapping[str, bool | int | float | str | DType | None] | None) – Compile-time parameters passed to the kernel. A value of None declares the parameter without giving it one yet, leaving any Param naming it unresolved (see CustomOp.is_complete).
• custom_extensions (Sequence[Path | str]) – Paths to the Mojo packages defining the kernel.

Returns:

An immutable CustomOp.

Raises:

• ValueError – If inputs or outputs is empty, or if neither custom_extensions nor the process-global overlay registers name.
• TypeError – If a dim names a symbol that is neither a Symbol nor a Param.
• MojoCompilationError – If a source package fails to compile.

Return type:

CustomOp