How to process various tasks like video acquisition parallel in Matlab? - camera

I want to acquire image data from stereo camera simultaneously, or in parallel, save somewhere and read the data when need.
Currently I am doing
for i=1:100
start([vid1 vid2]);
imageData1=getdata(vid1,1);
imageData2=getdata(vid2,1);
%do several calculations%
....
end
In this cameras are working serially and it is very slow. How can I make 2 cameras work at a time???
Please help..
P.S : I also tried parfor but it does not help .
Regards

No Parallel Computing Toolbox required!
The following solution can generally solve problems like yours:
First the videos, I just use some vectors as "data" and save them to the workspace, these would be your two video files:
% Creating of some "videos"
fakevideo1 = [1 ; 1 ; 1];
save('fakevideo1','fakevideo1');
fakevideo2 = [2 ; 2 ; 2];
save('fakevideo2','fakevideo2');
The basic trick is to create a function which generates another instance of Matlab:
function [ ] = parallelinstance( fakevideo_number )
% create command
% -sd (set directory), pwd (current directory), -r (run function) ...
% finally "&" to indicate background computation
command = strcat('matlab -sd',{' '},pwd,{' '},'-r "processvideo(',num2str(fakevideo_number),')" -nodesktop -nosplash &');
% call command
system( command{1} );
end
Most important is the use of & at the end of the terminal command!
Within this function another function is called where the actual video processing is done:
function [] = processvideo( fakevideo_number )
% create file and variable name
filename = strcat('fakevideo',num2str(fakevideo_number),'.mat');
varname = strcat('fakevideo',num2str(fakevideo_number));
% load video to workspace or whatever
load(filename);
A = eval(varname);
% do what has to be done
results = A*2;
% save results to workspace, file, grandmothers mailbox, etc.
save([varname 'processed'],'results');
% just to show that both processes run parallel
pause(5)
exit
end
Finally call the two processes in your main script:
% function call with number of video: parallelinstance(fakevideo_number)
parallelinstance(1);
parallelinstance(2);
My code is completely executable, so just play around a bit. I tried to keep it simple.
After all you will find two .mat files with the processed video "data" in your workspace.
Be aware to adjust the string fakevideo to name root of all your video files.

Related

Snakemake: variable that defines whether process is submitted cluster job or the snakefile

My current architecture is that at the start of my Snakefile I have a long running function somefunc which helps decide the "input" to rule all. I realized when I was running the workflow with slurm that somefunc is being executed by each job. Is there some variable I can access that defines whether the code is a submitted job or whether it is the main process:
if not snakemake.submitted_job:
config['layout'] = somefunc()
...
A solution which I don't really recommend is to make somefunc write the list of inputs to a tmp file so that slurm jobs will read this tmp file rather than reconstructing the list from scratch. The tmp file is created by whatever job is executed first so the long-running part is done only once.
At the end of the workflow delete the tmp file so that later executions will start fresh with new input.
Here's a sketch:
def somefunc():
try:
all_output = open('tmp.txt').readlines()
all_output = [x.strip() for x in all_output]
print('List of input files read from tmp.txt')
except:
all_output = ['file1.txt', 'file2.txt'] # Long running part
with open('tmp.txt', 'w') as fout:
for x in all_output:
fout.write(x + '\n')
print('List of input files created and written to tmp.txt')
return all_output
all_output = somefunc()
rule all:
input:
all_output,
rule one:
output:
all_output,
shell:
r"""
touch {output}
"""
onsuccess:
os.remove('tmp.txt')
onerror:
os.remove('tmp.txt')
Since jobs will be submitted in parallel, you should make sure that only one job writes tmp.txt and the others read it. I think the try/except above will do it but I'm not 100% sure. (Probably you want to use some better filename than tmp.txt, see the module tempfile. see also the module atexit) for exit handlers)
As discussed with #dariober it seems the cleanest to check whether the (hidden) snakemake directory has locks since they seem not to be generated until the first rule starts (assuming you are not using the --nolock argument).
import os
locked = len(os.listdir(".snakemake/locks")) > 0
However this results in a problem in my case:
import time
import os
def longfunc():
time.sleep(10)
return range(5)
locked = len(os.listdir(".snakemake/locks")) > 0
if not locked:
info = longfunc()
rule all:
input:
expand("test_{sample}", sample=info)
rule test:
output:
touch("test_{sample}")
run:
"""
sleep 1
"""
Somehow snakemake lets each rule reinterpret the complete snakefile, with the issue that all the jobs will complain that 'info is not defined'. For me it was easiest to store the results and load them for each job (pickle.dump and pickle.load).

IDL batch processing: fully automatic input selection

I need to process MODIS ocean level 2 data and I obtained an external plugin for ENVI https://github.com/dawhite/EPOC/releases. Now, I want to batch process hundreds of images for which I modified the code like the following code. The code is running fine, but I have to select the input file every time. Can anyone please help me to make the program fully automatic? I really appreciate and thanks a lot for your help!
Pro OCL2convert
dir = 'C:\MODIS\'
CD, dir
; batch processing of level 2 ocean chlorophyll data
files=file_search('*.L2_LAC_OC.x.hdf', count=numfiles)
; this command will search for all files in the directory which end with
; the specified one
counter=0
; this is a counter that tells IDL which file is being read-starts at 0
While (counter LT numfiles) Do begin
; this command tells IDL to start a loop and to only finish when the counter
; is equal to the number of files with the name specified
name=files(counter)
openr, 1, name
proj = envi_proj_create(/utm, zone=40, datum='WGS-84')
ps = [1000.0d,1000.0d]
no_bowtie = 0 ;same as not setting the keyword
no_msg = 1 ;same as setting the keyword
;OUTPUT CHOICES
;0 -> standard product only
;1 -> georeferenced product only
;2 -> standard and georeferenced products
output_choice = 2
;RETURNED VALUES
;r_fid -> ENVI FID for the standard product, if requested
;georef_fid -> ENVI FID for the georeferenced product, if requested
convert_oc_l2_data, fname=fname, output_path=output_path, $
proj=proj, ps=ps, output_choice=output_choice, r_fid=r_fid, $
georef_fid=georef_fid, no_bowtie=no_bowtie, no_msg=no_msg
print,'done!'
close, 1
counter=counter+1
Endwhile
End
Not knowing what convert_oc_l2_data does (it appears to be a program you created, there is no public documentation for it), I would say that the problem might be that the out_path variable is not defined in the rest of your program.

How to run same syntax on multiple spss files

I have 24 spss files in .sav format in a single folder. All these files have the same structure. I want to run the same syntax on all these files. Is it possible to write a code in spss for this?
You can use the SPSSINC PROCESS FILES user submitted command to do this or write your own macro. So first lets create some very simple fake data to work with.
*FILE HANDLE save /NAME = "Your Handle Here!".
*Creating some fake data.
DATA LIST FREE / X Y.
BEGIN DATA
1 2
3 4
END DATA.
DATASET NAME Test.
SAVE OUTFILE = "save\X1.sav".
SAVE OUTFILE = "save\X2.sav".
SAVE OUTFILE = "save\X3.sav".
EXECUTE.
*Creating a syntax file to call.
DO IF $casenum = 1.
PRINT OUTFILE = "save\TestProcess_SHOWN.sps" /"FREQ X Y.".
END IF.
EXECUTE.
Now we can use the SPSSINC PROCESS FILES command to specify the sav files in the folder and apply the TestProcess_SHOWN.sps syntax to each of those files.
*Now example calling the syntax.
SPSSINC PROCESS FILES INPUTDATA="save\X*.sav"
SYNTAX="save\TestProcess_SHOWN.sps"
OUTPUTDATADIR="save" CONTINUEONERROR=YES
VIEWERFILE= "save\Results.spv" CLOSEDATA=NO
MACRONAME="!JOB"
/MACRODEFS ITEMS.
Another (less advanced) way is to use the command INSERT. To do so, repeatedly GET each sav-file, run the syntax with INSERT, and sav the file. Probably something like this:
get 'file1.sav'.
insert file='syntax.sps'.
save outf='file1_v2.sav'.
dataset close all.
get 'file2.sav'.
insert file='syntax.sps'.
save outf='file2_v2.sav'.
etc etc.
Good luck!
If the Syntax you need to run is completely independent of the files then you can either use: INSERT FILE = 'Syntax.sps' or put the code in a macro e.g.
Define !Syntax ()
* Put Syntax here
!EndDefine.
You can then run either of these 'manually';
get file = 'file1.sav'.
insert file='syntax.sps'.
save outfile ='file1_v2.sav'.
Or
get file = 'file1.sav'.
!Syntax.
save outfile ='file1_v2.sav'.
Or if the files follow a reasonably strict naming structure you can embed either of the above in a simple bit of python;
Begin Program.
imports spss
for i in range(0, 24 + 1):
syntax = "get file = 'file" + str(i) + ".sav.\n"
syntax += "insert file='syntax.sps'.\n"
syntax += "save outfile ='file1_v2.sav'.\n"
print syntax
spss.Submit(syntax)
End Program.

AMPL:How to print variable output using NEOS Server, when you can't include data and model command in the command file?

I'm doing some optimization using a model whose number of constraints and variables exceeds the cap for the student version of, say, AMPL, so I've found a webpage [http://www.neos-server.org/neos/solvers/milp:Gurobi/AMPL.html] which can solve my type of model.
I've found however that when using a solver where you can provide a commandfile (which I assume is the same as a .run file) the documentation of NEOS server tells that you should see the documentation of the input file. I'm using AMPL input which according to [http://www.neos-guide.org/content/FAQ#ampl_variables] should be able to print the decision variables using a command file with the appearance:
solve;
display _varname, _var;
The problem is that NEOS claim that you cannot add the:
data datafile;
model modelfile;
commands into the .run file, resulting in that the compiler cannot find the variables.
Does anyone know of a way to work around this?
Thanks in advance!
EDIT: If anyone else has this problem (which I believe many people have based on my Internet search). Try to remove any eventual reset; command from the .run file!
You don't need to specify model or data commands in the script file submitted to NEOS. It loads the model and data files automatically, solves the problem, and then executes the script (command file) you provide. For example submitting diet1.mod model diet1.dat data and this trivial command file
display _varname, _var;
produces the output which includes
: _varname _var :=
1 "Buy['Quarter Pounder w/ Cheese']" 0
2 "Buy['McLean Deluxe w/ Cheese']" 0
3 "Buy['Big Mac']" 0
4 "Buy['Filet-O-Fish']" 0
5 "Buy['McGrilled Chicken']" 0
6 "Buy['Fries, small']" 0
7 "Buy['Sausage McMuffin']" 0
8 "Buy['1% Lowfat Milk']" 0
9 "Buy['Orange Juice']" 0
;
As you can see this is the output from the display command.

Nano hacks: most useful tiny programs you've coded or come across

It's the first great virtue of programmers. All of us have, at one time or another automated a task with a bit of throw-away code. Sometimes it takes a couple seconds tapping out a one-liner, sometimes we spend an exorbitant amount of time automating away a two-second task and then never use it again.
What tiny hack have you found useful enough to reuse? To make go so far as to make an alias for?
Note: before answering, please check to make sure it's not already on favourite command-line tricks using BASH or perl/ruby one-liner questions.
i found this on dotfiles.org just today. it's very simple, but clever. i felt stupid for not having thought of it myself.
###
### Handy Extract Program
###
extract () {
if [ -f $1 ] ; then
case $1 in
*.tar.bz2) tar xvjf $1 ;;
*.tar.gz) tar xvzf $1 ;;
*.bz2) bunzip2 $1 ;;
*.rar) unrar x $1 ;;
*.gz) gunzip $1 ;;
*.tar) tar xvf $1 ;;
*.tbz2) tar xvjf $1 ;;
*.tgz) tar xvzf $1 ;;
*.zip) unzip $1 ;;
*.Z) uncompress $1 ;;
*.7z) 7z x $1 ;;
*) echo "'$1' cannot be extracted via >extract<" ;;
esac
else
echo "'$1' is not a valid file"
fi
}
Here's a filter that puts commas in the middle of any large numbers in standard input.
$ cat ~/bin/comma
#!/usr/bin/perl -p
s/(\d{4,})/commify($1)/ge;
sub commify {
local $_ = shift;
1 while s/^([ -+]?\d+)(\d{3})/$1,$2/;
return $_;
}
I usually wind up using it for long output lists of big numbers, and I tire of counting decimal places. Now instead of seeing
-rw-r--r-- 1 alester alester 2244487404 Oct 6 15:38 listdetail.sql
I can run that as ls -l | comma and see
-rw-r--r-- 1 alester alester 2,244,487,404 Oct 6 15:38 listdetail.sql
This script saved my career!
Quite a few years ago, i was working remotely on a client database. I updated a shipment to change its status. But I forgot the where clause.
I'll never forget the feeling in the pit of my stomach when I saw (6834 rows affected). I basically spent the entire night going through event logs and figuring out the proper status on all those shipments. Crap!
So I wrote a script (originally in awk) that would start a transaction for any updates, and check the rows affected before committing. This prevented any surprises.
So now I never do updates from command line without going through a script like this. Here it is (now in Python):
import sys
import subprocess as sp
pgm = "isql"
if len(sys.argv) == 1:
print "Usage: \nsql sql-string [rows-affected]"
sys.exit()
sql_str = sys.argv[1].upper()
max_rows_affected = 3
if len(sys.argv) > 2:
max_rows_affected = int(sys.argv[2])
if sql_str.startswith("UPDATE"):
sql_str = "BEGIN TRANSACTION\\n" + sql_str
p1 = sp.Popen([pgm, sql_str],stdout=sp.PIPE,
shell=True)
(stdout, stderr) = p1.communicate()
print stdout
# example -> (33 rows affected)
affected = stdout.splitlines()[-1]
affected = affected.split()[0].lstrip('(')
num_affected = int(affected)
if num_affected > max_rows_affected:
print "WARNING! ", num_affected,"rows were affected, rolling back..."
sql_str = "ROLLBACK TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
sql_str = "COMMIT TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
ret_code = sp.call([pgm, sql_str], shell=True)
I use this script under assorted linuxes to check whether a directory copy between machines (or to CD/DVD) worked or whether copying (e.g. ext3 utf8 filenames -> fusebl
k) has mangled special characters in the filenames.
#!/bin/bash
## dsum Do checksums recursively over a directory.
## Typical usage: dsum <directory> > outfile
export LC_ALL=C # Optional - use sort order across different locales
if [ $# != 1 ]; then echo "Usage: ${0/*\//} <directory>" 1>&2; exit; fi
cd $1 1>&2 || exit
#findargs=-follow # Uncomment to follow symbolic links
find . $findargs -type f | sort | xargs -d'\n' cksum
Sorry, don't have the exact code handy, but I coded a regular expression for searching source code in VS.Net that allowed me to search anything not in comments. It came in very useful in a particular project I was working on, where people insisted that commenting out code was good practice, in case you wanted to go back and see what the code used to do.
I have two ruby scripts that I modify regularly to download all of various webcomics. Extremely handy! Note: They require wget, so probably linux. Note2: read these before you try them, they need a little bit of modification for each site.
Date based downloader:
#!/usr/bin/ruby -w
Day = 60 * 60 * 24
Fromat = "hjlsdahjsd/comics/st%Y%m%d.gif"
t = Time.local(2005, 2, 5)
MWF = [1,3,5]
until t == Time.local(2007, 7, 9)
if MWF.include? t.wday
`wget #{t.strftime(Fromat)}`
sleep 3
end
t += Day
end
Or you can use the number based one:
#!/usr/bin/ruby -w
Fromat = "http://fdsafdsa/comics/%08d.gif"
1.upto(986) do |i|
`wget #{sprintf(Fromat, i)}`
sleep 1
end
Instead of having to repeatedly open files in SQL Query Analyser and run them, I found the syntax needed to make a batch file, and could then run 100 at once. Oh the sweet sweet joy! I've used this ever since.
isqlw -S servername -d dbname -E -i F:\blah\whatever.sql -o F:\results.txt
This goes back to my COBOL days but I had two generic COBOL programs, one batch and one online (mainframe folks will know what these are). They were shells of a program that could take any set of parameters and/or files and be run, batch or executed in an IMS test region. I had them set up so that depending on the parameters I could access files, databases(DB2 or IMS DB) and or just manipulate working storage or whatever.
It was great because I could test that date function without guessing or test why there was truncation or why there was a database ABEND. The programs grew in size as time went on to include all sorts of tests and become a staple of the development group. Everyone knew where the code resided and included them in their unit testing as well. Those programs got so large (most of the code were commented out tests) and it was all contributed by people through the years. They saved so much time and settled so many disagreements!
I coded a Perl script to map dependencies, without going into an endless loop, For a legacy C program I inherited .... that also had a diamond dependency problem.
I wrote small program that e-mailed me when I received e-mails from friends, on an rarely used e-mail account.
I wrote another small program that sent me text messages if my home IP changes.
To name a few.
Years ago I built a suite of applications on a custom web application platform in PERL.
One cool feature was to convert SQL query strings into human readable sentences that described what the results were.
The code was relatively short but the end effect was nice.
I've got a little app that you run and it dumps a GUID into the clipboard. You can run it /noui or not. With UI, its a single button that drops a new GUID every time you click it. Without it drops a new one and then exits.
I mostly use it from within VS. I have it as an external app and mapped to a shortcut. I'm writing an app that relies heavily on xaml and guids, so I always find I need to paste a new guid into xaml...
Any time I write a clever list comprehension or use of map/reduce in python. There was one like this:
if reduce(lambda x, c: locks[x] and c, locknames, True):
print "Sub-threads terminated!"
The reason I remember that is that I came up with it myself, then saw the exact same code on somebody else's website. Now-adays it'd probably be done like:
if all(map(lambda z: locks[z], locknames)):
print "ya trik"
I've got 20 or 30 of these things lying around because once I coded up the framework for my standard console app in windows I can pretty much drop in any logic I want, so I got a lot of these little things that solve specific problems.
I guess the ones I'm using a lot right now is a console app that takes stdin and colorizes the output based on xml profiles that match regular expressions to colors. I use it for watching my log files from builds. The other one is a command line launcher so I don't pollute my PATH env var and it would exceed the limit on some systems anyway, namely win2k.
I'm constantly connecting to various linux servers from my own desktop throughout my workday, so I created a few aliases that will launch an xterm on those machines and set the title, background color, and other tweaks:
alias x="xterm" # local
alias xd="ssh -Xf me#development_host xterm -bg aliceblue -ls -sb -bc -geometry 100x30 -title Development"
alias xp="ssh -Xf me#production_host xterm -bg thistle1 ..."
I have a bunch of servers I frequently connect to, as well, but they're all on my local network. This Ruby script prints out the command to create aliases for any machine with ssh open:
#!/usr/bin/env ruby
require 'rubygems'
require 'dnssd'
handle = DNSSD.browse('_ssh._tcp') do |reply|
print "alias #{reply.name}='ssh #{reply.name}.#{reply.domain}';"
end
sleep 1
handle.stop
Use it like this in your .bash_profile:
eval `ruby ~/.alias_shares`