psblas3/test/comm/cg/README.md

CG no-preconditioner communication test

This test lives under test/comm/cg and builds a local executable:

• source: psb_comm_cg_test.F90
• executable: runs/psb_comm_cg_test

Behavior:

• generates a 3D PDE matrix using local psb_d_gen_pde3d (double precision)
• solves with CG
• uses preconditioner NONE
• runs CG three times, changing communication scheme of x each run

Communication pattern used in this test:

1. reset solution vector
2. set communication scheme on x%v%comm_handle
3. run full psb_krylov('CG', ...)
4. collect and compare solve time

Schemes compared:

• psb_comm_isend_irecv_
• psb_comm_ineighbor_alltoallv_
• psb_comm_persistent_ineighbor_alltoallv_

How to run

From this directory:

• make run (defaults: NP=4, IDIM=40)
• make run NP=8 IDIM=80

The program accepts one optional CLI argument: IDIM.