MPIDOUBLE

MPIDOUBLE is a term used in some parallel computing contexts to denote a data type representing a double-precision floating-point value in message-passing environments. It is not part of the official MPI (Message Passing Interface) specification as of the latest standards. In standard MPI, the corresponding predefined type is MPI_DOUBLE. MPIDOUBLE may appear as a user-defined alias or as documentation shorthand in certain projects, extensions, or tutorials, but its exact definition is not standardized and can vary between implementations.

Typical characteristics attributed to MPIDOUBLE align with a 64-bit IEEE 754 double, occupying eight bytes and subject to the platform's alignment requirements. In a codebase that uses MPIDOUBLE, communication routines would, in principle, treat MPIDOUBLE similarly to MPI_DOUBLE: a contiguous sequence of double-precision values; however, portability depends on the library supporting such a type alias. If used as a custom datatype, it would usually require explicit datatype creation and commitment, such as defining the corresponding MPI datatype and ensuring correctness of packing and unpacking across processes.

Advantages of using a nonstandard alias include readability or compatibility with legacy code. Limitations include lack of portability and potential mismatch with compilers or runtimes that assume standard MPI types. See also MPI_DOUBLE, MPI_Type_create_struct, MPI_Send, MPI_Recv.