IMPI_C_COLL_MAXLINEAR

Each client contributes an IMPI_Int4 that indicates the minimum number of hosts for which relevant collective calls will use logrithmic protocols. Relevant collective calls with fewer hosts than this value will use linear protocols.

Clients must provide a way for users to choose this value. If the user does not select a value, the client will contribute -1, indicating that that client wants the default value for this label. If the user does select a value (which must be $\ge 0$), that value is sent. All clients must contribute the same value, or an error occurs.

The default value for IMPI_C_COLL_MAXLINEAR for IMPI version 0.0 is 4.