cleanup

README.md

@@ -11,3 +11,79 @@ process
 - clean mlir-tutorial code []
 - create a basic pass using cpp mechanism []
 - update basic version with more ranks (e.g., -n-ranks=10) []
+
+## Examples
+
+### A + B (partition in halfs)
+
+Input:
+
+```mlir
+func.func @add_arrays(%A: memref<100xf32>, %B: memref<100xf32>, %C: memref<100xf32>) {
+  affine.for %i = 0 to 100 {
+    %a = memref.load %A[%i] : memref<100xf32>
+    %b = memref.load %B[%i] : memref<100xf32>
+    %sum = arith.addf %a, %b : f32
+    memref.store %sum, %C[%i] : memref<100xf32>
+  }
+  return
+}
+```
+
+Output:
+
+```mlir
+func.func @add_arrays_mpi(%A: memref<100xf32>, %B: memref<100xf32>, %C: memref<100xf32>) {
+    %c0 = arith.constant 0 : i32
+    %c1 = arith.constant 1 : i32
+    %c50 = arith.constant 50 : index  // Half of 100
+
+    // Get MPI rank
+    %init_err = mpi.init : !mpi.retval
+    %rank_err, %rank = mpi.comm_rank : !mpi.retval, i32
+
+    // Process based on rank
+    %zero = arith.constant 0 : i32
+    %is_rank_zero = arith.cmpi eq, %rank, %zero : i32
+    scf.if %is_rank_zero {
+      // Process 0 sends first half of data
+      %send_err1 = mpi.send(%A, %c1, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+      %send_err2 = mpi.send(%B, %c1, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+
+      // Process local half
+      affine.for %i = 50 to 100 {
+        %a = memref.load %A[%i] : memref<100xf32>
+        %b = memref.load %B[%i] : memref<100xf32>
+        %sum = arith.addf %a, %b : f32
+        memref.store %sum, %C[%i] : memref<100xf32>
+      }
+
+      // Receive processed first half
+      %recv_err = mpi.recv(%C, %c1, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+
+    } else {
+      // Process 1 receives and processes first half
+      %local_a = memref.alloc() : memref<100xf32>
+      %local_b = memref.alloc() : memref<100xf32>
+      %local_result = memref.alloc() : memref<100xf32>
+
+      %recv_err1 = mpi.recv(%local_a, %c0, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+      %recv_err2 = mpi.recv(%local_b, %c0, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+
+      affine.for %i = 0 to 50 {
+        %a = memref.load %local_a[%i] : memref<100xf32>
+        %b = memref.load %local_b[%i] : memref<100xf32>
+        %sum = arith.addf %a, %b : f32
+        memref.store %sum, %local_result[%i] : memref<100xf32>
+      }
+
+      %send_err = mpi.send(%local_result, %c0, %c0) : memref<100xf32>, i32, i32 -> !mpi.retval
+
+      memref.dealloc %local_a : memref<100xf32>
+      memref.dealloc %local_b : memref<100xf32>
+      memref.dealloc %local_result : memref<100xf32>
+    }
+
+    return
+}
+```