Read the specification for an output type from a spec file and generate it.

Parameters

[in,out]	file	Spec file.
[out]	output_type	Kernel type.

The output type is specified by the parameter:

output_type (string): type of disk output — must be one of: central to write one file per process, but all written by process 0; dist for every process to write its own state file; or single to transfer all data to process 0 and write a single unified output file