[GRASS-dev] [GRASS GIS] #2356: r.stream.basisns uses more memory than given in memory option

[GRASS GIS]

#2356: r.stream.basisns uses more memory than given in memory option
--------------------------------------+-------------------------------------
 Reporter:  sbl                       |       Owner:  grass-dev@…              
     Type:  defect                    |      Status:  new                      
 Priority:  normal                    |   Milestone:  7.1.0                    
Component:  Raster                    |     Version:  svn-trunk                
 Keywords:  r.stream.basisns, memory  |    Platform:  Linux                    
      Cpu:  x86-64                    |  
--------------------------------------+-------------------------------------
 I tried to run r.stream.basins on using large flow direction / stream maps
 generated with r.watershed.

 With m-flag and memory option set to 35GB (~2/3 of the RAM of my system)
 the process got killed (by out-of-mmemory-killer) after input maps were
 read.

 So, I re-ran the module with a smaller amount of memory allocated (20 and
 10 GB) in the memory option and monitored memory usage (UNIX top command).
 There I found that r.stream.basisns used 2x the amount of RAM allowed, on
 each input map. In other words, with memory=10000, it used

 20GB for reading flow direction map, plus

 20GB for reading streams map (40GB in total).

 Finally, the process gets killed when it starts finding nodes.

 I am using Ubuntu 12.04 LTS 64bit and GRASS 7.0 (revision 58620).

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/2356>
GRASS GIS <http://grass.osgeo.org>