diff --git a/src/main.py b/src/main_cg.py
similarity index 85%
rename from src/main.py
rename to src/main_cg.py
index 05314ae..23eaac4 100644
--- a/src/main.py
+++ b/src/main_cg.py
@@ -12,7 +12,7 @@ comm = MPI.COMM_WORLD
 size = comm.Get_size()
 rank = comm.Get_rank()
 
-n = 1_00
+n = 1_000
 h = 1 / (n - 1)
 
 A = Matrix([-1, 2, -1], structure="tridiagonal", n=n)
@@ -21,5 +21,5 @@ b = Vector([h**2 * 2] * n)
 
 x = cg.cg(A, x0, b)
 
-if rank == 0:
-    print(x)
+# if rank == 0:
+#     print(f"ranks = {size}: x = {x}")
diff --git a/src/main_cg_timeit.py b/src/main_cg_timeit.py
new file mode 100644
index 0000000..e8f3000
--- /dev/null
+++ b/src/main_cg_timeit.py
@@ -0,0 +1,27 @@
+from mpi4py import MPI
+import sys
+import timeit
+
+import cg
+
+from matrix_mpi import MatrixMPI as Matrix
+from vector_mpi import VectorMPI as Vector
+
+# from matrix import Matrix
+# from vector import Vector
+
+comm = MPI.COMM_WORLD
+size = comm.Get_size()
+rank = comm.Get_rank()
+
+n = int(sys.argv[1])
+h = 1 / (n - 1)
+
+A = Matrix([-1, 2, -1], structure="tridiagonal", n=n)
+x0 = Vector([1] * n)
+b = Vector([h**2 * 2] * n)
+
+time = timeit.timeit(lambda: cg.cg(A, x0, b), number=1)
+
+if rank == 0:
+    print(f"ranks = {size}: time = {time}")
diff --git a/src/main_diag_vec.py b/src/main_diag_vec.py
new file mode 100644
index 0000000..7cd4db1
--- /dev/null
+++ b/src/main_diag_vec.py
@@ -0,0 +1,21 @@
+from mpi4py import MPI
+
+from matrix_mpi import MatrixMPI as Matrix
+from vector_mpi import VectorMPI as Vector
+
+# from matrix import Matrix
+# from vector import Vector
+
+comm = MPI.COMM_WORLD
+size = comm.Get_size()
+rank = comm.Get_rank()
+
+n = 10_000
+
+A = Matrix([3], structure="diagonal", offset=0, n=n)
+v = Vector([7] * n)
+
+x = A * v
+
+# if rank == 0:
+#     print(f"ranks = {size}: x = {x}")
diff --git a/src/main_diag_vec_timeit.py b/src/main_diag_vec_timeit.py
new file mode 100644
index 0000000..c4be531
--- /dev/null
+++ b/src/main_diag_vec_timeit.py
@@ -0,0 +1,23 @@
+from mpi4py import MPI
+import sys
+import timeit
+
+from matrix_mpi import MatrixMPI as Matrix
+from vector_mpi import VectorMPI as Vector
+
+# from matrix import Matrix
+# from vector import Vector
+
+comm = MPI.COMM_WORLD
+size = comm.Get_size()
+rank = comm.Get_rank()
+
+n = int(sys.argv[1])
+
+A = Matrix([3], structure="diagonal", offset=0, n=n)
+v = Vector([7] * n)
+
+time = timeit.timeit(lambda: A * v, number=1)
+
+if rank == 0:
+    print(f"ranks = {size}: time = {time}s")
diff --git a/src/main_matrix_vec.py b/src/main_matrix_vec.py
new file mode 100644
index 0000000..4366170
--- /dev/null
+++ b/src/main_matrix_vec.py
@@ -0,0 +1,22 @@
+from mpi4py import MPI
+
+from matrix_mpi import MatrixMPI as Matrix
+from vector_mpi import VectorMPI as Vector
+
+# from matrix import Matrix
+# from vector import Vector
+
+comm = MPI.COMM_WORLD
+size = comm.Get_size()
+rank = comm.Get_rank()
+
+n = 10_000
+
+m_data = [(i / k) for i in range(1, n+1) for k in range(1, n+1)]
+A = Matrix(m_data, (n, n))
+v = Vector(list(range(1, n+1)))
+
+x = A * v
+
+# if rank == 0:
+#     print(f"ranks = {size}: x = {x}")
diff --git a/src/main_matrix_vec_timeit.py b/src/main_matrix_vec_timeit.py
new file mode 100644
index 0000000..2903676
--- /dev/null
+++ b/src/main_matrix_vec_timeit.py
@@ -0,0 +1,24 @@
+from mpi4py import MPI
+import sys
+import timeit
+
+from matrix_mpi import MatrixMPI as Matrix
+from vector_mpi import VectorMPI as Vector
+
+# from matrix import Matrix
+# from vector import Vector
+
+comm = MPI.COMM_WORLD
+size = comm.Get_size()
+rank = comm.Get_rank()
+
+n = int(sys.argv[1])
+
+m_data = [(i / k) for i in range(1, n+1) for k in range(1, n+1)]
+A = Matrix(m_data, (n, n))
+v = Vector(list(range(1, n+1)))
+
+time = timeit.timeit(lambda: A * v, number=1)
+
+if rank == 0:
+    print(f"ranks = {size}: time = {time}s")
diff --git a/src/matrix_mpi.py b/src/matrix_mpi.py
index c23f53f..5ef8883 100644
--- a/src/matrix_mpi.py
+++ b/src/matrix_mpi.py
@@ -100,6 +100,9 @@ class MatrixMPI:
         """
         return self.transpose()
 
+    def __str__(self):
+        return str(self.__data__)
+
     def __eq__(self, other):
         """
         Return ``self==value``
diff --git a/src/vector_mpi.py b/src/vector_mpi.py
index 35341e0..bcb8f21 100644
--- a/src/vector_mpi.py
+++ b/src/vector_mpi.py
@@ -1,7 +1,6 @@
 import math
 
 import numpy
-from mpi4py import MPI
 
 from matrix_mpi import MatrixMPI
 from vector import Vector