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Increasing double loop efficiency
I replaced the double loop with DGEMM in my code. The DGEMM is run inside three other loops and the whole code is run in parallel across 4 nodes of 64 cores each. When using the double DO loop, the total run time is 7h19m. With DGEMM replacing the double loop, the runtime is 3h34m, a... -
Increasing double loop efficiency
I will try both cases using 1) the two do loops, and 2) DGEMM, to see which is faster. It may well be that they are similar in speed. Thanks, Vahid -
Increasing double loop efficiency
Thanks mikrom for your response. Out of curiosity, wouldn't it be more efficient to define A as a column matrix, B as a row matrix and set K=1? Wouldn't this involve fewer calculations? Vahid -
Increasing double loop efficiency
I have the following double loop; DO i=1,100 DO j=1,100 S(i,j)= S(i,j)+ALPHA*exp[(real(i)/b1)**2]*exp[(real(j)/b2)**2] ENDDO ENDDO Here, S is a 100x100 symmetric REAL array, ALPHA, b1, and b2 are REAL constants. I am hoping to incorporate LAPACK dgemm or some other library function... -
Preventing the addition of C-style comments in gfortran compilation
Thanks for the link. In addition, I also added the tag "-nostdinc" to CPP. Now the code compiles. Cheers, Vahid -
Preventing the addition of C-style comments in gfortran compilation
...The codes includes about 50 files. When I issue "make", the compilation crashes because somehow the following lines get added to .f files. /* Copyright (C) 1991-2016 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can... -
Printing in a fortran MPI/OpenMP environment
If I do not know the printout is of the master node or both nodes, I am not sure how to define success here. -
Printing in a fortran MPI/OpenMP environment
This is likely a very simple question. I am running a fortran code compiled in hybrid openmp/openmpi. The code runs on 2 nodes (128 processors) with 32 MPI processes and 4 threads/MPI process. I am attempting to verify that a variable involved in the calculations on all the MPI processes and... -
Broadcasting a REAL number to another file
With trial and error, I managed to resolve the issue. By broadcast I meant broadcast across nodes so that all the nodes running the code can see the parameter. I had to make the parameter global by adding a SAVE statement. Anyhow, the issue is resolved but thank you xwb for taking the time to... -
Broadcasting a REAL number to another file
Hi, I am modifying a large code called Perturbo. Here I attempt to describe what the problem is with a simple example. I understand that this information may not be enough. The code has a module file called polar_dispersion.f90. I would like to broadcast the value of a REAL called conc (not... -
Do loop in ascending and descending order
Thank you Salgerman. Your solution is far more elegant than mine. I need to remove the duplicate lines but that is easy. Best wishes, Vahid -
Do loop in ascending and descending order
Hello, I found a not-so-elegant way to do this: For a 2-d grid, I use the following: n=0 do n2=nstart(2),nmax(2) if (MOD(n2,2)==0) then do n3=nstart(3),nmax(3) n=n+1 k(2,n)=n2-1... -
Do loop in ascending and descending order
...nstart(3),tmp(3),k(3,npts) nmax(1)=4; nmax(2)=4; nmax(3)=4 nstart(1)=1; nstart(2)=1; nstart(3)=1 ntot=nmax(1)*nmax(2)*nmax(3) do n1=nstart(1),nmax(1) do n2=nstart(2),nmax(2) do n3=nstart(3),nmax(3)... -
Reading files inside many numbered folders
Thanks xwb. It worked. I just had to use i5.5 instead of i5 in the format statement to get the leading zeros. Best wishes, Vahid -
Reading files inside many numbered folders
...the content of a.dat, save the necessary information to an array and then move on to the next folder. I declared a CHARACTER as such: CHARACTER(*), PARAMETER :: fileplace ="/home/vahid/scratch/K" The I run a DO loop over the folders: DO f=1,100 OPEN(unit=100,'(a,i5,a)')... -
NaN output outside but not inside DO loop
Thanks Mikrom. The NaN seem to be related to compiling with ifort which is the compiler I used. When I compile with gfortran, I get the same result as yours. Best wishes, Vahid -
NaN output outside but not inside DO loop
...kb = 1.3806488e-23 ! J/K REAL, PARAMETER :: qq = 1.60217657e-19 ! eV REAL, PARAMETER :: bohr_2_cm = 5.2917721067e-9 kT = kb*temp/qq ! eV EVmax=6.28 EVmin=-5.83 ECmax=21.47 ECmin=6.8 V=262.8707 PRINT*, "Enter DOS file... -
Transfer of data from inside a subroutine to main program
Thank you Mikrom. The interface made it work. Best wishes, Vahid -
Transfer of data from inside a subroutine to main program
Hi Bill and Mikrom, Thank you for your responses. I have not used common blocks in the past and so I will look into it. I tried using "contains" before. The actual code has several other subroutines and using "contains" results in a lot of other errors which without the subroutine f(r), those... -
Transfer of data from inside a subroutine to main program
...to be able to use r(i) inside the subroutine. Program Test IMPLICIT NONE real,dimension(1) :: r CALL f(r) write(*,*) r subroutine f(r) implicit none integer :: i real, intent(out) :: r(i) do i = 1, 10 r = 2*i...
