snap_stats

Purpose:

Perform computations of the mean, standard deviation, minimum, and maximum of a variable with sampling paced by an external synchronization event.

Enter:

snap_stats <reg_name> <priority> <interval> [+c] &

Where:

reg_name

Specify a unique registration name that allows multiple instances of this task to be run. The name “SnapStat” is the name used for default specifications (where there is no @REG_NAME in the spec file).

priority

Specify the system priority level of the process.

interval

Specify the time interval, in milliseconds, indicating how often the master scheduler will be informed that this process is still running. Specify one of the FAS, MED, or SLO intervals specified in the go script.

+c

Optional. Specify this flag to indicate the process is considered to be a critical task. The watchdog will be triggered if the process abnormally terminates.

Example:

snap_stats SnapStat121000 &

The above spawns the Snap Statistics process, snap_stats at a system priority level of 12 and would signal the master scheduler once every second. The registered name of this instance will be “SnapStat”.

Configure the “snap_stats” application using the “snap_specs” translator application. The default spec file name is /specs/ss_specs.NNN (where NNN is the test cell name). 

Below is an example spec file:

# the @REG_NAME keyword is optional – the default registered name is SnapStat  
@REG_NAME  
   SnapStat  
 
####################################################################  
# this is an example specification file for the snap_stats task  
#  
# There can be 8 groups of specs in this file, each with a distinct  
# set of controlling events.  Each group can have 64 variables.  
#  
# Separate each group with a $ symbol  
#  
#######################################################################  
#sample_event   compute_event     compute_done_event   clear_event  
take_sample     compute_result    compute_done         clear_buffers  
 
#list of variables ( 100 max )  
#in_variable      stat_variable(output)  
my_x              my_x.  
my_x2             my_x2.  
my_x3             my_stat.  
#ldots  
#  
$  
 
#sample_event   compute_event     compute_done_event   clear_event  
sample          compute_result    –                    clear_buffers  
 
#list of variables ( 100 max )  
#variable      stat_variable(output)  
an_x           an_x.  
#ldots  
 
$

Notes:

 

See Also:

snap_specs, Statistical Variables and Sampling