Hi Christine,
only_on_root looks like this:
only_on_root(func, *args, **kwargs)
So the idea here is that it accepts the function handle, any
positional arguments, and any keyword arguments. Your commands look
like this:
file = only_on_root(open(filename,'w'))
only_on_root(file.write("hello_world \n"))
only_on_root(file.close())
The first translation would look like:
file = only_on_root(open, filename, 'w')
but then you'll run into problems with the second two, because they
will require the attributes 'close' and 'write' on the file object,
which is going to be None on the non-root procs. So your best bet is
a variant of what Britton suggested:
def write_file():
file = open(filename,'w')
file.write("hello_world \n"))
file.close()
only_on_root(write_file)
-Matt
On Tue, Nov 22, 2011 at 11:49 AM, Christine Simpson
Hi,
I'm trying to run a script with parallel yt that does some non-yt io. I'm a little confused about how to use only_on_root.
Here is a test script I've tried:
from yt.mods import * from yt.visualization.api import PlotCollection
import matplotlib.colorbar as cb
path = "/scratch/01112/tg803911/halo88_therm_feed_3.7e-6_LW_RadiationShield_lmax12/DD0010/" fn = "output_0010" pf = load(path+fn) pc = PlotCollection(pf) pc.add_projection("Density",0) pc.set_width(20,'kpc') pc.save(fn)
filename = 'hello_world'
file = only_on_root(open(filename,'w')) only_on_root(file.write("hello_world \n")) only_on_root(file.close())
Pasted below is the error. I'm uncertain about the syntax of only_on_root. Do I just wrap it around normal commands? Also, it seems that the write command is trying to execute on all the processors. That shouldn't be happening, right?
P007 yt : [INFO ] 2011-11-22 09:50:20,558 Saved output_0010_Projection_x_Density.png P008 yt : [INFO ] 2011-11-22 09:50:20,558 Saved output_0010_Projection_x_Density.png P009 yt : [INFO ] 2011-11-22 09:50:20,560 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> File "test_parallel_yt.py", line 19, in <module> Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' only_on_root(file.write("hello_world \n")) AttributeError : only_on_root(file.write("hello_world \n")) 'NoneType' object has no attribute 'write' P010 yt : [INFO ] 2011-11-22 09:50:20,561 Saved output_0010_Projection_x_Density.png AttributeErrorP011 yt : [INFO ] 2011-11-22 09:50:20,561 Saved output_0010_Projection_x_Density.png : 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) Traceback (most recent call last): AttributeError: File "test_parallel_yt.py", line 19, in <module> 'NoneType' object has no attribute 'write' P005 yt : [INFO ] 2011-11-22 09:50:20,562 Saved output_0010_Projection_x_Density.png P004 yt : [INFO ] 2011-11-22 09:50:20,562 Saved output_0010_Projection_x_Density.png only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P002 yt : [INFO ] 2011-11-22 09:50:20,583 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P001 yt : [INFO ] 2011-11-22 09:50:20,589 Saved output_0010_Projection_x_Density.png P003 yt : [INFO ] 2011-11-22 09:50:20,589 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P013 yt : [INFO ] 2011-11-22 09:50:20,593 Saved output_0010_Projection_x_Density.png P014 yt : [INFO ] 2011-11-22 09:50:20,593 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P012 yt : [INFO ] 2011-11-22 09:50:20,596 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P015 yt : [INFO ] 2011-11-22 09:50:20,599 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 19, in <module> only_on_root(file.write("hello_world \n")) AttributeError: 'NoneType' object has no attribute 'write' P000 yt : [INFO ] 2011-11-22 09:50:21,410 Saved output_0010_Projection_x_Density.png Traceback (most recent call last): File "test_parallel_yt.py", line 18, in <module> file = only_on_root(open(filename,'w')) File "/share/home/01112/tg803911/yt_17May2011/yt-x86_64/src/yt-hg/yt/funcs.py", line 357, in only_on_root return func(*args, **kwargs) TypeError: 'file' object is not callable mpispawn.c:303 Unexpected exit status
Child exited abnormally! Killing remote processes...DONE
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