It is not intended to be used as a fortran language reference manual although chapter 8 does contain a detailed guide to the features of inputoutput whilst chapter 23 gives details of. The guide concentrates on compilerspecific features and those areas of the fortran language where the fortran 95 standard1 needs amplification. Sun microsystems fortran on solaris reports the processs run time on the cpu, while gfortran on linux reports the aggregate cpu time of all the processs threads. These two intrinsics report different types of time. Sign up example fortran programs for introduction to fortran for scientists and engineers class. The fortran panel offers options related specifically to the fortran compiler. Users on unix systems could access a system library routine called etime for this purpose, but etime was not part of the fortran language, and was not to be found on other operating systems. Here is how fortran decides single processor or multiple processor. In many cases, a single fortran compiler is used to compile. Fortran intrinsic timing routines, which is better. Runtime library routines on tru64 unix and linux systems. In the sentence, a fortran 9590 subroutine is the equivalent of a function of type void in c, the word.
Abaqus user subroutine with open file statement using multicore cpu is possible or not. Fortran subroutines for network flow optimization using an. Again my experience is limited to the win environment. In many, of not most, cases, the time it takes to execute a program is not important. Values returns the user and system components of this time in values1 and values2 respectively. Library functions that return the time of day or elapsed cpu time vary from system to system. The total actual cpu time is the sum of the actual user cpu time and actual system cpu time. The fortran library functions provide an interface from fortran programs to the irix system functions. Use of data statement in recursive routines in fortran 77 use of the data statement also produces compiler dependent results.
Multiple processorswallclock time while processing your program. The approach taken by sun allows one to compute the total execution time. Enabling this option can provide speed benefits at the cost of compatibility. This intrinsic is provided in both subroutine and function forms. Most problems that require a computer program to solve them are too complex to sit down and work all the way through them in one go.
Getprocesstimes is the only routine to return cpu time, while the others return elapsed time. The time measured only accounts for the amount of time that the program is actually running, and not the time that a program is suspended or waiting. For example, such a subroutine might simply set a flag in a common block and return to the calling program. Cpu that provides a distinct environment in which to use a product in this case, a language. The main gfortran compiler option is o, although o1, o2, and o3 also. Using subprograms allows you to tackle bite size pieces of a problem individually. When the compile strictly for selection option is enabled, the resultant target will not run on cpu s that do not possess the features specified in the target cpu s dropdown box.
The overall runtime and filereading time for the single serial run were measured as 756. It returns the time in seconds since the beginning of execution of the program. This worksheet makes use of several examples programs that are all available for download from this website. An easy introduction to cuda fortran nvidia developer blog. Getprocesstimes suffers from poor resolution when i have tested it. There is a bit of a discussion on this stack overflow. The functions maxloc and minloc are extended with the optional dim argument. The fortran 77 compiler processes each source file to convert the fortran 77 statements into their equivalent in the lowlevel machine code for the target computer. Both of these routines return the elapsed time from a single clock.
This is normally the computer on which the fortran 77 program is being compiled, but it could be a computer with a different type of cpu, in which case it is known as cross. Abaqus user subroutine with open file statement using. Understand the use of subroutines and functions to make your code more efficient and easier to read. The following time functions are not supported directly in the sun fortran libraries, but you can write subroutines to duplicate their functions. In many cases, a single fortran compiler is used to compile fortran77 and fortran90 codes. System functions are facilities that are provided by the irix system kernel directly, as opposed to functions that are supplied by library code linked with your program.
Pgi visual fortran compiler users guide version 19. Functions and subroutines are fortrans subprograms. The time functions supported in the sun fortran library are listed in the following table. Note that time may contain a, system dependent, arbitrary offset and may not start with 0.
The intrinsic functions ceiling and floor now take the optional kind argument. The program codes are written in the fortran 9095 language with mpi and openmp. The cuda fortran compiler is a part of the pgi compilers which can be downloaded from pgis web site, which offers a free 15day trial license. Returns the cpu time, in seconds, taken by the current process and, possibly, all the child processes in all of the threads. Nag fortran compiler frequently asked questions nag. Openmpaccelerated swat simulation using intel c and. The program sets up some arrays and then outputs them. Please let me know if any one have tried abaqus user subroutine with open file statement using multicore cpu. It is possible on return from an interrupt subroutine to continue from the point at which execution was interrupted, provided that the subroutine neither performs fortran inputoutput calls nor any other system routine. The first time you use the registers window, the cpu registers are shown by default.
Time dependent density functional theory tddft calculations can be performed on 100,000 cpu cores of k computer with high parallel efficiency. Rightclick in the registers window to bring up a context menu. Program main integer n, x external sub1 common globals n x 0 print, enter number of repeats read, n call sub1x,sub1 end subroutine sub1x,dumsub integer n. The output of the macsyma code is a complete fortran subroutine, using macsyma to write fortran subroutines 215 the macsyma code contains several steps. Consider the following variation on the fortran 77 code from example 1.
1384 1665 1669 341 744 879 92 1547 351 1244 1658 1392 1238 808 1522 1067 1113 1528 131 801 87 1407 664 464 204 1435 839 1397 156 1082 65 554 952 1511 1404 878 546 224 407 1322 260 163 1134 365 750 802