Attempt to use rFactor for allreduce

[wujingyue]

mpirun -np 1 -x NVFUSER_DUMP=fusion_ir_preseg pytest tests/python/test_communication.py -k allreduce_rfactor -s --only-mpi

%kernel {
T2_l_float[iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3}] (DeviceMesh{0})
   = reduction( T0_g_float[iS0{2}, ideviceIdx.x6{1}, iS7{5}, iS2{3}] (DeviceMesh{0}), op = add, initial value = float(0), allreduce = false )
T1_g_float[iS15{2}, rS16{1}, iS17{3}] (DeviceMesh{0})
   = reduction( T2_l_float[iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3}] (DeviceMesh{0}), op = add, initial value = float(0), allreduce = false )

TransformPrinter :
T0_g_float[iS0{2}, ideviceIdx.x6{1}, iS7{5}, iS2{3}] (DeviceMesh{0})
 logical domain : (iS0{2}, iS1{5}, iS2{3})
 allocation domain : (iS0{2}, ideviceIdx.x6{1}, iS7{5}, iS2{3})
 contiguity: t t t t
  Outer split: iS1{5} by factor 1 -> ideviceIdx.x6{1}, iS7{5}
 loop domain : (iS0{2}, ideviceIdx.x6{1}, iS7{5}, iS2{3})
T2_l_float[iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3}] (DeviceMesh{0})
 root domain : (iS10{2}, rS11{5}rf, iS12{3})
  Outer split: rS11{5}rf by factor 1 -> ideviceIdx.x13{1}rf, rS14{5}rf
 logical domain : (iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3})
 allocation domain : (iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3})
 contiguity: t t n t
 loop domain : (iS10{2}, ideviceIdx.x13{1}rf, rS14{5}rf, iS12{3})
T1_g_float[iS15{2}, rS16{1}, iS17{3}] (DeviceMesh{0})
 logical domain : (iS15{2}, rS16{1}, iS17{3})
 allocation domain : (iS15{2}, rS16{1}, iS17{3})
 contiguity: t n t
 loop domain : (iS15{2}, rS16{1}, iS17{3})
} // %kernel

RuntimeError:  INTERNAL ASSERT FAILED at "/opt/pytorch/nvfuser/csrc/scheduler/vectorize_helper.cpp":1063, please report a bug with repro script to NVFuser at https://github.com/NVIDIA/Fuser/issues. Unexpected producer RF ID: iS2{3}
Exception raised from getVectorizationBreakPointOfReductionProducer at /opt/pytorch/nvfuser/csrc/scheduler/vectorize_helper.cpp:1063 (most recent call first):

[naoyam]

What does the actual fusion that is passed to the reduction scheduler look like?