Compiling the programs

All the programs in each subdirectory directory can be compiled by typing make at the command prompt.

Note that in order to compile pi_mpi.cc the MPI development headers and libraries must be available. In a system using Lmod environment modules this can be accomplished by typing a command like module load openmpi or module load mpich.

Description and instructions

Subdirectory compute_pi

• pi_serial.cc

  This program computes an approximation of pi using a serial algorithm. The actual computation is done by approximating the integral of 4/(1+x^2) on the interval [0,1] with the midpoint rule with 400,000,000 subintervals.

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  این برنامه با استفاده از یک سریال تقریبی از پی را محاسبه می کند الگوریتم محاسبه واقعی با تقریب انجام می شود انتگرال 4/(1+x^2) در بازه [0,1] با قانون نقطه میانی با 400000000 زیر بازه.

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• pi_omp.cc

  Same as above except OpenMP is used to provide multithreading if supported by the hardware. In particular, a parallel thread is created for each processor or processor core on the machine. This can be overridden by setting the environment variable OMP_NUM_THREADS. For example OMP_NUM_THREADS=1 ./pi_omp will force the program to use a single thread regardless of of the hardware.

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  مانند بالا به جز OpenMP برای ارائه multithreading if استفاده می شود توسط سخت افزار پشتیبانی می شود. به طور خاص، یک موضوع موازی است برای هر پردازنده یا هسته پردازشگر روی دستگاه ایجاد شده است. این را می توان با تنظیم متغیر محیطی لغو کرد «OMP_NUM_THREADS». برای مثال «OMP_NUM_THREADS=1 ./pi_omp» خواهد بود برنامه را مجبور به استفاده از یک رشته بدون توجه به سخت افزار

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• pi_mpi.cc

  This version uses MPI and is suitable for distributed memory system like a cluster. To run on a single multicore machine, use

  mpiexec -n <N> ./pi_mpi

  with replaced by the number of processes to be used. To run on a cluster try

  mpiexec -machinefile <file> -n <N> ./pi_mpi

  where <file> is a file containing the names of the individual machines that comprise the cluster. If the cluster has the resource manager SLURM then try

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  که در آن "" فایلی است که نام هر ماشینی را شامل می شود که خوشه را تشکیل می دهند. اگر خوشه دارای مدیر منبع SLURM باشد پس تلاش کن

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  salloc -Q -n <N> mpiexec ./pi_mpi

Subdirectory matrix_matrix_multiply

• matmat_c1.c - Matrices are statically allocated 2-Dimensional arrays

  Since the value of N is known at compile-time, the matrices are declared with statements like double a[N][N]. They are global so that they will not be allocated on the stack. The (i,j) array element is referred to with a[i][j].

• matmat_c2.c - Matrices are dynamically allocated 1-Dimensional arrays (row-major)

  The C library routine malloc() is used to allocate each matrix as an (N^2)-element one-dimensional array. A macro IDX() is defined to facilitate indexing into the array using row and column values and here assumes a row-major ordering, i.e., elements along a row in the matrix are stored consecutively in memory. The (i,j) array element is referred to with a[IDX(i,j,stride)] where stride is the matrix row length.

• matmat_c3.c - Matrices are dynamically allocated 1-Dimensional arrays (column-major)

  Same as matmat_c2.c except column-major ordering is used. The only change to the code is the definition of the IDX() macro. This also means that stride is the matrix column length.

• matmat_c4.c - Matrices are dynamically allocated using an array of pointers

  To allow dynamic memory allocation but to facilitate normal C-style two-dimensional array indexing even when matrices are passed as function parameters, this program allocates an (N^2)-element one-dimensional array to hold the matrix data but additionally allocates an N-element one-dimensional array of pointers. Each element of this latter array is set to point to the first element of a matrix row. The (i,j) array element is referred to with a[i][j].

• matmat_f77.f - Written in FORTRAN 77

• matmat_ijk.c - Template with ijk and jki loop-orderings; user writes for ikj, jik, kij, and kji orderings.

• matmat_ijk_macro.c - same as matmat_ijk.c except this version uses 1D arrays for the matrices and a macro for indexing.