//if not set (use of the algo directly, without mvapich2 selector)
if(MV2_Scatter_intra_function==NULL)
MV2_Scatter_intra_function=Coll_scatter_mpich::scatter;
//if not set (use of the algo directly, without mvapich2 selector)
if(MV2_Scatter_intra_function==NULL)
MV2_Scatter_intra_function=Coll_scatter_mpich::scatter;