[FLASH-USERS] Big Problem??
Tomasz Plewa
tplewa at fsu.edu
Wed Jul 30 06:46:10 EDT 2008
Seyit -
To begin with, you are using 2 different processor architectures, 3
different Linux kernels, 3 different Fortran compilers,
and, finally, 3 different versions of one mpi implementation (mpich). In
this situation it is expected that you will see at least some variation
in results of floating point calculations (1) due to different processor
even if you use the same compiler (i.e. pc1 vs pc3) or (2) compiler even
if you use the same architecture (i.e. pc2 vs pc3). Kernel may play some
rather minimal role and mpi version is perhaps even the least concern.
So the bottom line is: differences in numerical results are expected
even at t=0. And since you are working with a physically unstable
problem, physics will pick up that additional perturbative signal and
drive solutions over sightly different trajectories.
Are those differences important? Well, that depends on what you are
after. If sheer numerics and consistency of floating point calculcations
is crucial, perhaps yes. That might a computer science question. But if
physics is of primary concern then you need to judge from the evolution
of the system. Formally, you may want to do a convergence study and
check whether all your models converge to the same solution (using some
metric and norm). If not, pick one system that does converge. Please
keep in mind that convergence in a sense of numerical solution does not
imply correctness in terms of physics. This aspect of numerical modeling
is once in a while confused...
Tomek
--
Seyit Hocuk wrote:
> Hi Tomek good morning,
>
> Let me answer your first question.
>
> * /Any luck with a single block/single level runs? /
>
> Nope. Even single level (lref_min = lref_max) runs differ in dt_hydro.
> That means I don't use refinement at all. I guess it is also affecting
> the end results. I have to do a complete simulation again to be sure.
> But the initial files show small differences already.
>
> Here the initial results.
> Note 1: the differences in precision in k, kJ, c0 etc...
> Note 2: pc 1 and 3 are not that much differen, but grow more different
> later on.
>
>
> *pc 1*
>
> flash: initializing for jeans problem.
>
> kx = 7.8539816E-20 ky = 1.5707963E-19 kz = 0.0000000E+00
>
> k = 1.756203682760181E-019
> kJ = 6.508776532382562E-019
> c0 = 181807.294175918 omega^2 = -1.298354260861123E-026
> velamp = 64881.6252564676
> perturbation is unstable with growth time 8776137041619.21
> min_blocks 5 max_blocks 5 tot_blocks 5
> min_blocks 21 max_blocks 21 tot_blocks 21
> min_blocks 85 max_blocks 85 tot_blocks 85
> min_blocks 341 max_blocks 341 tot_blocks 341
> INITIAL TIMESTEP = 100000.000000000 [CHECKPOINT_WR] NOTE: will
> send 520 blocks per message.
> Warning! The HDF5 header files included by this application do not
> match the
> version used by the HDF5 library to which this application is linked.
> Data
> corruption or segmentation faults may occur if the application is
> allowed to continue. You can, at your own risk, disable this check by
> setting
> the environment variable 'HDF5_DISABLE_VERSION_CHECK' to a value of '1'.
> Setting it to 2 will suppress the warning totally.
> Headers are 1.6.6, library is 1.6.7
> Bye...
> forrtl: info: Fortran error message number is 76.
> forrtl: warning: Could not open message catalog: ifcore_msg.cat.
> forrtl: info: Check environment variable NLSPATH and protection of
> /usr/lib/ifcore_msg.cat.
> Abort
> [1] + Done emacs flash.par
> [seyit at celsius objectT3]$ setenv HDF5_DISABLE_VERSION_CHECK 1
> [seyit at celsius objectT3]$ ./flash2
>
> flash: initializing for jeans problem.
>
> kx = 7.8539816E-20 ky = 1.5707963E-19 kz = 0.0000000E+00
>
> k = 1.756203682760181E-019
> kJ = 6.508776532382562E-019
> c0 = 181807.294175918 omega^2 = -1.298354260861123E-026
> velamp = 64881.6252564676
> perturbation is unstable with growth time 8776137041619.21
> min_blocks 5 max_blocks 5 tot_blocks 5
> min_blocks 21 max_blocks 21 tot_blocks 21
> min_blocks 85 max_blocks 85 tot_blocks 85
> min_blocks 341 max_blocks 341 tot_blocks 341
> INITIAL TIMESTEP = 100000.000000000 [CHECKPOINT_WR] NOTE: will
> send 520 blocks per message.
> [CHECKPOINT_WR] Writing checkpoint file jeans_r13vA_hdf5_chk_0000
> Progress: |
> *** Wrote output to jeans_r13vA_hdf5_chk_0000 ( 341 blocks ) ***
> number of variables found for plotfile storage = 3
> dens pres temp
> *** Wrote output to jeans_r13vA_hdf5_plt_cnt_0000 ***
> n t dt | dt_hydro
> 1 2.0000E+05 2.0000E+05 | 4.240E+11
> 2 6.0000E+05 4.0000E+05 | 4.240E+11
> 3 1.4000E+06 8.0000E+05 | 4.240E+11
> 4 3.0000E+06 1.6000E+06 | 4.240E+11
> 5 6.2000E+06 3.2000E+06 | 4.240E+11
> 6 1.2600E+07 6.4000E+06 | 4.240E+11
> 7 2.5400E+07 1.2800E+07 | 4.240E+11
> 8 5.1000E+07 2.5600E+07 | 4.240E+11
> 9 1.0220E+08 5.1200E+07 | 4.240E+11
> 10 2.0460E+08 1.0240E+08 | 4.240E+11
> 11 4.0940E+08 2.0480E+08 | 4.241E+11
> 12 8.1900E+08 4.0960E+08 | 4.241E+11
> 13 1.6382E+09 8.1920E+08 | 4.241E+11
> 14 3.2766E+09 1.6384E+09 | 4.242E+11
> 15 6.5534E+09 3.0000E+09 | 4.243E+11
> 16 1.2553E+10 3.0000E+09 | 4.247E+11
> 17 1.8553E+10 3.0000E+09 | 4.250E+11
> 18 2.4553E+10 3.0000E+09 | 4.255E+11
> 19 3.0553E+10 3.0000E+09 | 4.259E+11
> 20 3.6553E+10 3.0000E+09 | 4.266E+11
> 21 4.2553E+10 3.0000E+09 | 4.273E+11
> 22 4.8553E+10 3.0000E+09 | 4.281E+11
> 23 5.4553E+10 3.0000E+09 | 4.288E+11
> 24 6.0553E+10 3.0000E+09 | 4.296E+11
> 25 6.6553E+10 3.0000E+09 | 4.304E+11
> 26 7.2553E+10 3.0000E+09 | 4.313E+11
> 27 7.8553E+10 3.0000E+09 | 4.321E+11
> 28 8.4553E+10 3.0000E+09 | 4.330E+11
> 29 9.0553E+10 3.0000E+09 | 4.339E+11
> 30 9.6553E+10 3.0000E+09 | 4.348E+11
> 31 1.0255E+11 3.0000E+09 | 4.357E+11
> 32 1.0855E+11 3.0000E+09 | 4.366E+11
> 33 1.1455E+11 3.0000E+09 | 4.301E+11
> 34 1.2055E+11 3.0000E+09 | 3.803E+11
> 35 1.2655E+11 3.0000E+09 | 3.379E+11
> 36 1.3255E+11 3.0000E+09 | 3.057E+11
> 37 1.3855E+11 3.0000E+09 | 2.868E+11
> 38 1.4455E+11 3.0000E+09 | 2.876E+11
> 39 1.5055E+11 3.0000E+09 | 2.880E+11
> 40 1.5655E+11 3.0000E+09 | 2.903E+11
> 41 1.6255E+11 3.0000E+09 | 2.936E+11
> 42 1.6855E+11 3.0000E+09 | 2.978E+11
> 43 1.7455E+11 3.0000E+09 | 4.475E+11
> 44 1.8055E+11 3.0000E+09 | 4.486E+11
> 45 1.8655E+11 3.0000E+09 | 4.496E+11
> 46 1.9255E+11 3.0000E+09 | 4.507E+11
> 47 1.9855E+11 3.0000E+09 | 4.517E+11
> 48 2.0455E+11 3.0000E+09 | 4.528E+11
> 49 2.1055E+11 3.0000E+09 | 4.538E+11
> 50 2.1655E+11 3.0000E+09 | 4.549E+11
>
>
>
> *pc 2*
>
> flash: initializing for jeans problem.
>
> kx = 7.8539816E-20 ky = 1.5707963E-19 kz = 0.0000000E+00
>
> k = 1.7562036827601810E-019
> kJ = 6.5087765323825604E-019
> c0 = 181807.2941759182 omega^2 = -1.2983542608611234E-026
> velamp = 64881.62525646757
> perturbation is unstable with growth time 8776137041619.213
> min_blocks 5 max_blocks 5 tot_blocks 5
> min_blocks 21 max_blocks 21 tot_blocks 21
> min_blocks 85 max_blocks 85 tot_blocks 85
> min_blocks 341 max_blocks 341 tot_blocks 341
> INITIAL TIMESTEP = 100000.0000000000 [CHECKPOINT_WR] NOTE:
> will send 520 blocks per message.
> [CHECKPOINT_WR] Writing checkpoint file jeans_r13vA_hdf5_chk_0000
> Progress: |
> *** Wrote output to jeans_r13vA_hdf5_chk_0000 ( 341 blocks ) ***
> number of variables found for plotfile storage = 3
> dens pres temp
> *** Wrote output to jeans_r13vA_hdf5_plt_cnt_0000 ***
> n t dt | dt_hydro
> 1 2.0000E+05 2.0000E+05 | 4.406E+11
> 2 6.0000E+05 4.0000E+05 | 4.406E+11
> 3 1.4000E+06 8.0000E+05 | 4.406E+11
> 4 3.0000E+06 1.6000E+06 | 4.406E+11
> 5 6.2000E+06 3.2000E+06 | 4.406E+11
> 6 1.2600E+07 6.4000E+06 | 4.406E+11
> 7 2.5400E+07 1.2800E+07 | 4.406E+11
> 8 5.1000E+07 2.5600E+07 | 4.406E+11
> 9 1.0220E+08 5.1200E+07 | 4.406E+11
> 10 2.0460E+08 1.0240E+08 | 4.405E+11
> 11 4.0940E+08 2.0480E+08 | 4.404E+11
> 12 8.1900E+08 4.0960E+08 | 4.403E+11
> 13 1.6382E+09 8.1920E+08 | 4.399E+11
> 14 3.2766E+09 1.6384E+09 | 4.393E+11
> 15 6.5534E+09 3.0000E+09 | 4.381E+11
> 16 1.2553E+10 3.0000E+09 | 4.365E+11
> 17 1.8553E+10 3.0000E+09 | 4.353E+11
> 18 2.4553E+10 3.0000E+09 | 4.345E+11
> 19 3.0553E+10 3.0000E+09 | 4.340E+11
> 20 3.6553E+10 3.0000E+09 | 4.337E+11
> 21 4.2553E+10 3.0000E+09 | 4.337E+11
> 22 4.8553E+10 3.0000E+09 | 4.339E+11
> 23 5.4553E+10 3.0000E+09 | 4.343E+11
> 24 6.0553E+10 3.0000E+09 | 4.348E+11
> 25 6.6553E+10 3.0000E+09 | 4.355E+11
> 26 7.2553E+10 3.0000E+09 | 4.363E+11
> 27 7.8553E+10 3.0000E+09 | 4.371E+11
> 28 8.4553E+10 3.0000E+09 | 4.382E+11
> 29 9.0553E+10 3.0000E+09 | 4.393E+11
> 30 9.6553E+10 3.0000E+09 | 4.405E+11
> 31 1.0255E+11 3.0000E+09 | 4.418E+11
> 32 1.0855E+11 3.0000E+09 | 4.431E+11
> 33 1.1455E+11 3.0000E+09 | 4.447E+11
> 34 1.2055E+11 3.0000E+09 | 4.463E+11
> 35 1.2655E+11 3.0000E+09 | 4.479E+11
> 36 1.3255E+11 3.0000E+09 | 4.496E+11
> 37 1.3855E+11 3.0000E+09 | 4.513E+11
> 38 1.4455E+11 3.0000E+09 | 4.531E+11
> 39 1.5055E+11 3.0000E+09 | 4.550E+11
> 40 1.5655E+11 3.0000E+09 | 4.570E+11
> 41 1.6255E+11 3.0000E+09 | 4.590E+11
> 42 1.6855E+11 3.0000E+09 | 4.611E+11
> 43 1.7455E+11 3.0000E+09 | 4.632E+11
> 44 1.8055E+11 3.0000E+09 | 4.653E+11
> 45 1.8655E+11 3.0000E+09 | 4.675E+11
> 46 1.9255E+11 3.0000E+09 | 4.697E+11
> 47 1.9855E+11 3.0000E+09 | 4.719E+11
> 48 2.0455E+11 3.0000E+09 | 4.733E+11
> 49 2.1055E+11 3.0000E+09 | 4.734E+11
> 50 2.1655E+11 3.0000E+09 | 4.736E+11
>
>
>
> *pc 3*
>
>
> flash: initializing for jeans problem.
>
> kx = 7.8539816E-20 ky = 1.5707963E-19 kz = 0.0000000E+00
>
> k = 1.756203682760181E-019
> kJ = 6.508776532382562E-019
> c0 = 181807.294175918 omega^2 = -1.298354260861123E-026
> velamp = 64881.6252564676
> perturbation is unstable with growth time 8776137041619.21
> min_blocks 5 max_blocks 5 tot_blocks 5
> min_blocks 21 max_blocks 21 tot_blocks 21
> min_blocks 85 max_blocks 85 tot_blocks 85
> min_blocks 341 max_blocks 341 tot_blocks 341
> INITIAL TIMESTEP = 100000.000000000 [CHECKPOINT_WR] NOTE: will
> send 520 blocks per message.
> [CHECKPOINT_WR] Writing checkpoint file jeans_r13vA_hdf5_chk_0000
> Progress: |
> *** Wrote output to jeans_r13vA_hdf5_chk_0000 ( 341 blocks ) ***
> number of variables found for plotfile storage = 3
> dens pres temp
> *** Wrote output to jeans_r13vA_hdf5_plt_cnt_0000 ***
> n t dt | dt_hydro
> 1 2.0000E+05 2.0000E+05 | 4.240E+11
> 2 6.0000E+05 4.0000E+05 | 4.240E+11
> 3 1.4000E+06 8.0000E+05 | 4.240E+11
> 4 3.0000E+06 1.6000E+06 | 4.240E+11
> 5 6.2000E+06 3.2000E+06 | 4.240E+11
> 6 1.2600E+07 6.4000E+06 | 4.240E+11
> 7 2.5400E+07 1.2800E+07 | 4.240E+11
> 8 5.1000E+07 2.5600E+07 | 4.240E+11
> 9 1.0220E+08 5.1200E+07 | 4.240E+11
> 10 2.0460E+08 1.0240E+08 | 4.240E+11
> 11 4.0940E+08 2.0480E+08 | 4.241E+11
> 12 8.1900E+08 4.0960E+08 | 4.241E+11
> 13 1.6382E+09 8.1920E+08 | 4.241E+11
> 14 3.2766E+09 1.6384E+09 | 4.242E+11
> 15 6.5534E+09 3.0000E+09 | 4.244E+11
> 16 1.2553E+10 3.0000E+09 | 4.247E+11
> 17 1.8553E+10 3.0000E+09 | 4.251E+11
> 18 2.4553E+10 3.0000E+09 | 4.255E+11
> 19 3.0553E+10 3.0000E+09 | 4.259E+11
> 20 3.6553E+10 3.0000E+09 | 4.266E+11
> 21 4.2553E+10 3.0000E+09 | 4.273E+11
> 22 4.8553E+10 3.0000E+09 | 4.281E+11
> 23 5.4553E+10 3.0000E+09 | 4.288E+11
> 24 6.0553E+10 3.0000E+09 | 4.296E+11
> 25 6.6553E+10 3.0000E+09 | 4.304E+11
> 26 7.2553E+10 3.0000E+09 | 4.313E+11
> 27 7.8553E+10 3.0000E+09 | 4.321E+11
> 28 8.4553E+10 3.0000E+09 | 4.330E+11
> 29 9.0553E+10 3.0000E+09 | 4.338E+11
> 30 9.6553E+10 3.0000E+09 | 4.347E+11
> 31 1.0255E+11 3.0000E+09 | 4.356E+11
> 32 1.0855E+11 3.0000E+09 | 4.366E+11
> 33 1.1455E+11 3.0000E+09 | 4.375E+11
> 34 1.2055E+11 3.0000E+09 | 4.384E+11
> 35 1.2655E+11 3.0000E+09 | 4.394E+11
> 36 1.3255E+11 3.0000E+09 | 4.404E+11
> 37 1.3855E+11 3.0000E+09 | 4.413E+11
> 38 1.4455E+11 3.0000E+09 | 4.423E+11
> 39 1.5055E+11 3.0000E+09 | 4.433E+11
> 40 1.5655E+11 3.0000E+09 | 4.444E+11
> 41 1.6255E+11 3.0000E+09 | 4.454E+11
> 42 1.6855E+11 3.0000E+09 | 4.464E+11
> 43 1.7455E+11 3.0000E+09 | 4.474E+11
> 44 1.8055E+11 3.0000E+09 | 4.484E+11
> 45 1.8655E+11 3.0000E+09 | 4.495E+11
> 46 1.9255E+11 3.0000E+09 | 4.505E+11
> 47 1.9855E+11 3.0000E+09 | 4.516E+11
> 48 2.0455E+11 3.0000E+09 | 4.526E+11
> 49 2.1055E+11 3.0000E+09 | 4.537E+11
> 50 2.1655E+11 3.0000E+09 | 4.547E+11
>
>
>
>
> *here again the 3 different pc's*
>
>
> 1)
> Centos5
> Linux celsius 2.6.18-53.1.19.el5 #1 SMP Wed May 7 08:20:19 EDT 2008
> i686 i686 i386 GNU/Linux
> ifort intel compiler version 8.0
> hdf5 1.6.6 (serial) *(updated recently to 1.6.7)*
> mpich2 Version: 1.0.3
> gcc version 4.1.2 20070626 (Red Hat 4.1.2-14)
> FFLAGS_OPT = -c -r8 -i4 -fast -ipo -ipo_obj -I $(MPI_PATH)/include
>
> 2)
> Debian (??)
> Linux hpcibm1 2.6.8-11-amd64-k8-smp #1 SMP Sun Oct 2 20:03:22 UTC 2005
> x86_64 GNU/Linux
> pgf90 6.0-5 32-bit target on x86-64 Linux
> hdf5 1.4.5 (serial)
> mpich2 version 1.0.5
> gcc version 3.3.5 (Debian 1:3.3.5-13)
> FFLAGS_OPT = -c -fast -r8 -i4
>
> 3)
> Ubuntu
> Linux si01 2.6.24.3 #1 SMP Fri Jul 4 11:02:09 CEST 2008 x86_64 GNU/Linux
> ifort intel compiler version 10.1.012
> hdf5 1.6.7 (serial)
> mpich2 Version: 1.0.6
> gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)
> FFLAGS_OPT = -c -r8 -i4 -xT -O3 -no-prec-div -static -I
> $(MPI_PATH)/include
> or (only -ipo difference, result seemingly doesn't change)
> FFLAGS_OPT = -c -r8 -i4 -fast -I $(MPI_PATH)/include
>
>
>
>
>
>
> Tomasz Plewa wrote:
>> Seyit -
>>
>> Avoiding aggressive optimization is certainly good idea when it comes
>> to debugging implementation. Alas, given you experience problems with
>> 3 different compilers it is rather unlilkely that compilers are at
>> fault.
>>
>> If your grid does not resolve structures correctly (persumably due to
>> lax refinement criteria), the code may quite easily produce an
>> unphysical state. But that should not happen during the initial grid
>> generation.
>>
>> Any luck with a single block/single level runs?
>>
>> Tomek
>> --
>> Seyit Hocuk wrote:
>>> Hi,
>>>
>>> It has been some time now, but to continue the discussion, I have
>>> tested Jeans standard problem and Sedov standard problem including
>>> changing the refinement levels. The result is exactly same for all
>>> three different computers. Unfortunately my own setup shows
>>> differences and it seems the end result changes by the coice of
>>> computer/environment/compiler whatever. My own setup has a lot more
>>> physics than the simpe test problems.
>>>
>>> One thing I am thinking about is that I adjusted the refinement
>>> criteria to use a reference density instead of looking at the second
>>> order derivative. I don't know if this could be the problem, but
>>> dt_hydro should not depend on the refinement criteria so I guess
>>> there is more to it.
>>>
>>> Unfortunately it is not easy to change compilers and some other
>>> stuff (like cpu/kernel etc.) on the different computers because I
>>> have limited rights on those machines. I don't want to find out I
>>> have to choose one machine and stick with it. How do I know which
>>> machine is the best. Anyway, I am going to try at least to get the
>>> libraries the same (hdf5 / mpi) for all machines and see if that
>>> helps. Btw the latest hdf5 (1.8.1) doesn't seem to work with Flash2.5.
>>>
>>> I will also play with compiler options. Try to make them exactly the
>>> same and avoid aggressive optimizations. I hope this is where the
>>> solution lies.
>>>
>>> Thanks,
>>> Seyit
>>>
>>>
>>>
>>>
>>> Tomasz Plewa wrote:
>>>> Although I prefer a low cost approach to debugging which avoids
>>>> dealing with setup/system/compiler information at first and
>>>> attempts to eliminate 99% of the source code, here are quick
>>>> comments on your systems.
>>>>
>>>> (1) pgi 6.0 is a quite antique compiler. It's so old that now I do
>>>> not even remember what problems we may have had with it. I suspect
>>>> quite a few and none of them might be relevant...
>>>>
>>>> (2) As you might noticed, intel has a newer compiler version. Your
>>>> CentOS5 system needs upgrades on both mpich2 and compiler sides.
>>>>
>>>> (3) Your Ubuntu system seems relatively up-to-date although HDF5
>>>> 1.8.x is out there and seems working fine.
>>>>
>>>> (4) Compilers are known to do strange things to perfect codes! So
>>>> if you run into a trouble on a new system, one of the first things
>>>> to try is to lower compiler optimization level. Avoiding -fast or
>>>> -ip or -inline is usually a good idea. Simple -O0 may suffice for a
>>>> couple of steps. As a bonus, the code compiles fast. Then the trick
>>>> is to get it crashing quickly...
>>>>
>>>> Again, I suggest to simplify your application, isolate the problem,
>>>> fix it, then find the best compiler, mpich, options, etc., to run
>>>> your production code.
>>>>
>>>> Enjoy your weekend!
>>>>
>>>> Tomek
>>>> --
>>>> Seyit Hocuk wrote:
>>>>> Hi Nathan,
>>>>>
>>>>> Thats a good Idea, I'll start simple and test those first thing
>>>>> monday. It's too late for me now.
>>>>>
>>>>> To answer your questions:
>>>>>
>>>>> The problem I am running is my own home made, actually it's a
>>>>> modified version of Jeans. Basically including heat, cool, eos
>>>>> gamma, compositions, adjusted refinement criteria similar to one
>>>>> of the other problems (with delta_ref and delta_deref) and a scala
>>>>> of other small things.
>>>>>
>>>>> 1)
>>>>> Centos5
>>>>> Linux celsius 2.6.18-53.1.19.el5 #1 SMP Wed May 7 08:20:19 EDT
>>>>> 2008 i686 i686 i386 GNU/Linux
>>>>> ifort intel compiler version 8.0
>>>>> hdf5 1.6.6 (serial)
>>>>> mpich2 Version: 1.0.3
>>>>> gcc version 4.1.2 20070626 (Red Hat 4.1.2-14)
>>>>> FFLAGS_OPT = -c -r8 -i4 -fast -ipo -ipo_obj -I
>>>>> $(MPI_PATH)/include
>>>>>
>>>>> 2)
>>>>> Debian (??)
>>>>> Linux hpcibm1 2.6.8-11-amd64-k8-smp #1 SMP Sun Oct 2 20:03:22 UTC
>>>>> 2005 x86_64 GNU/Linux
>>>>> pgf90 6.0-5 32-bit target on x86-64 Linux
>>>>> hdf5 1.4.5 (serial)
>>>>> mpich2 version 1.0.5
>>>>> gcc version 3.3.5 (Debian 1:3.3.5-13)
>>>>> FFLAGS_OPT = -c -fast -r8 -i4
>>>>>
>>>>> 3)
>>>>> Ubuntu
>>>>> Linux si01 2.6.24.3 #1 SMP Fri Jul 4 11:02:09 CEST 2008 x86_64
>>>>> GNU/Linux
>>>>> ifort intel compiler version 10.1.012
>>>>> hdf5 1.6.7 (serial)
>>>>> mpich2 Version: 1.0.6
>>>>> gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)
>>>>> FFLAGS_OPT = -c -r8 -i4 -xT -O3 -no-prec-div -static -I
>>>>> $(MPI_PATH)/include
>>>>> or (only -ipo difference, result seemingly doesn't change)
>>>>> FFLAGS_OPT = -c -r8 -i4 -fast -I $(MPI_PATH)/include
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Nathan Hearn wrote:
>>>>>> Hi Seyit,
>>>>>>
>>>>>> Are you seeing these differences in the standard test problems
>>>>>> included in Flash (e.g., Noh, Sod, Sedov), or are they specific
>>>>>> to the
>>>>>> problem that you are running. (Really, this follows from Tomek's
>>>>>> advice to look at the simplest configurations where the differences
>>>>>> are seen.)
>>>>>>
>>>>>> Also, it would be good to include some more information in your
>>>>>> messages, for instance: the problem that you are running, the
>>>>>> specific
>>>>>> architectures and compilers, the optimization flags, and the library
>>>>>> versions for HDF5 and MPI that you are using. Details like these
>>>>>> can
>>>>>> be really helpful in evaluating and fixing the issues you are
>>>>>> seeing.
>>>>>>
>>>>>>
>>>>>> - Nathan
>>>>>>
>>>>>>
>>>>>> On Fri, Jul 18, 2008 at 11:32 AM, Seyit Hocuk
>>>>>> <seyit at astro.rug.nl> wrote:
>>>>>>
>>>>>>> Oh man,
>>>>>>>
>>>>>>> I am using 3 different computers (with different architectures,
>>>>>>> compilers,
>>>>>>> optimizations, environments). All three start differently
>>>>>>> immediately from
>>>>>>> the beginning (difference in dt_hydro and refinement).
>>>>>>> Should I worry very very very much?
>>>>>>> I'm now doing a complete simulation and am going to check if my
>>>>>>> end results
>>>>>>> also change.
>>>>>>>
>>>>>>> I'm trembling by the thought.....
>>>>>>>
>>>>>
>>>>>
>>>>
>>>
>
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