You have completed the Using Coarray Fortran tutorial. The source file: mcpi_coarray_final.f90 should contain a completed version of the coarray application. This source includes a modification to ensure that the random number sequence is different on each image. Initializations that are based on the time-of-day may yield the same seed on more than one image if the clock had the same value. See the source for more detail.
For more complete information about compiler optimizations, see our Optimization Notice.