[slurm-users] Odd behavior/bug with --array env SLURM_ARRAY_TASK_MAX

[Robert Anderson]

While working on an example python slurm job script I found the
environment variable SLURM_ARRAY_TASK_MAX was not set to the expected
value when a step is defined.

Below is a minimal test of a 10 array job, with a step value of 5.  When
a step value is defined the SLURM_ARRAY_TASK_MAX is set to the maximum
value that slurm will provide as a SLURM_ARRAY_TASK_ID, not the
actual expected "array max value".

Current behavior looses the only hook to the real "array max" value.
I can think of no reason why the current behavior would be preferred
over my expected value. 

Am I missing something?


We are using "slurm 17.02.2" on SL7.3 kernel 3.10.0-229.20.1.el7.x86_64.  
Searches reveal very little information on SLURM_ARRAY_TASK_MAX, so I
do not believe this has been previously reported and/or fixed.


Thanks in advance for any clarification and/or bug acknowledgment.  If
it really is a bug how do I officially report it.  Is this the correct
place?

----- slurm_test.py -----

#!/usr/bin/python                                                                                 
#SBATCH --array=0-9:5%2
import os
print('''                                                                                         
ID={e[SLURM_ARRAY_TASK_ID]}                                                                       
MIN={e[SLURM_ARRAY_TASK_MIN]}                                                                     
MAX={e[SLURM_ARRAY_TASK_MAX]}                                                                     
''').format(e=os.environ)

----- shell run -----

bash-4.2$ sbatch --version
slurm 17.02.2
bash-4.2$ sbatch slurm_test.py
Submitted batch job 20610
bash-4.2$ ls slurm-20610_*
slurm-20610_0.out  slurm-20610_5.out
bash-4.2$ cat slurm-20610_*

ID=0
MIN=0
MAX=5


ID=5
MIN=0
MAX=5




-- 
--------------------------------------------------
Robert E. Anderson -- (603) 862-3489
Associate Director -- UNH Research Computing Center    
http://www.unh.edu/research/rcc
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