lab12 init

lab12/sieve_e.cpp

@@ -0,0 +1,67 @@
+#include <vector>
+#include <iostream>
+#include <mpi.h>
+
+std::vector<int> get_start_condition(int N, int count_proc, int rank)
+{
+    int total_elements = N - 1; // because range starts at 2
+    int base_chunk = total_elements / count_proc;
+    int remainder = total_elements % count_proc;
+
+    int start_offset = rank * base_chunk + std::min(rank, remainder);
+    int chunk_size = base_chunk + (rank < remainder ? 1 : 0);
+
+    int start = 2 + start_offset;
+    int end = start + chunk_size; // exclusive
+
+    std::vector<int> start_set;
+    for (int i = start; i < end; ++i)
+    {
+        start_set.emplace_back(i);
+    }
+
+    return start_set;
+}
+
+
+// mark element as not prim by setting to 0
+
+// 2,3,4
+// 0,1,2
+// even numbers are at even indices
+// index is (number - 2) or (number - start)
+
+void sieve(std::vector<int> &set, int k)
+{
+  for (int &elem : set)
+  {
+    if ((elem != k) && (elem != 0) && (elem % k == 0))
+    {
+      elem = 0;
+    }
+  }
+}
+
+void print_vec(std::vector<int> vec)
+{
+  for (int elem : vec)
+  {
+    std::cout << elem << ", ";
+  }
+  std::cout << std::endl;
+}
+
+int main(int argc, char *argv[])
+{
+  // MPI_Init(&argc, &argv);
+  int procs = atoi(argv[1]);
+  int N = atoi(argv[2]);
+  std::cout << "Procs: " << procs << " N: " << N << std::endl;
+  for (int proc = 0; proc < procs; proc++)
+  {
+    std::vector<int> elems = get_start_condition(N, procs, proc);
+    print_vec(elems);
+  }
+
+  // MPI_Finalize();
+}