X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/fdbef7b63085492ddbc9201726508d63d0c8bf8f..360b5d19eb0cb595fd34d11aa6426d95b3c974d4:/doc/user/topics/tutorial-parallel.html.textile.liquid diff --git a/doc/user/topics/tutorial-parallel.html.textile.liquid b/doc/user/topics/tutorial-parallel.html.textile.liquid index 21d9841c7e..d7a093a245 100644 --- a/doc/user/topics/tutorial-parallel.html.textile.liquid +++ b/doc/user/topics/tutorial-parallel.html.textile.liquid @@ -6,7 +6,7 @@ title: "Parallel Crunch tasks" In the previous tutorials, we used @arvados.job_setup.one_task_per_input_file()@ to automatically parallelize our jobs by creating a separate task per file. For some types of jobs, you may need to split the work up differently, for example creating tasks to process different segments of a single large file. In this this tutorial will demonstrate how to create Crunch tasks directly. -Start by entering the @crunch_scripts@ directory of your git repository: +Start by entering the @crunch_scripts@ directory of your Git repository:
~$ cd you/crunch_scripts
@@ -17,7 +17,7 @@ Next, using @nano@ or your favorite Unix text editor, create a new file called @
 
 notextile. 
~/you/crunch_scripts$ nano parallel-hash.py
-Add the following code to compute the md5 hash of each file in a +Add the following code to compute the MD5 hash of each file in a collection: {% code 'parallel_hash_script_py' as python %} @@ -25,7 +25,7 @@ Make the file executable: notextile.
~/you/crunch_scripts$ chmod +x parallel-hash.py
-Next, add the file to @git@ staging, commit and push: +Add the file to the Git staging area, commit, and push:
~/you/crunch_scripts$ git add parallel-hash.py
@@ -34,13 +34,14 @@ Next, add the file to @git@ staging, commit and push:
 
-You should now be able to run your new script using Crunch, with "script" referring to our new "parallel-hash.py" script. We will use a different input from our previous examples. We will use @887cd41e9c613463eab2f0d885c6dd96+83@ which consists of three files, "alice.txt", "bob.txt" and "carol.txt" (the example collection used previously in "fetching data from Arvados using Keep":tutorial-keep.html). +You should now be able to run your new script using Crunch, with "script" referring to our new "parallel-hash.py" script. We will use a different input from our previous examples. We will use @887cd41e9c613463eab2f0d885c6dd96+83@ which consists of three files, "alice.txt", "bob.txt" and "carol.txt" (the example collection used previously in "fetching data from Arvados using Keep":{{site.baseurl}}/user/tutorials/tutorial-keep.html#dir).
~/you/crunch_scripts$ cat >~/the_job <<EOF
 {
  "script": "parallel-hash.py",
- "script_version": "you:master",
+ "repository": "$USER",
+ "script_version": "master",
  "script_parameters":
  {
   "input": "887cd41e9c613463eab2f0d885c6dd96+83"
@@ -62,13 +63,13 @@ EOF
 
+(Your shell should automatically fill in @$USER@ with your login name. The job JSON that gets saved should have @"repository"@ pointed at your personal Git repository.) + Because the job ran in parallel, each instance of parallel-hash creates a separate @md5sum.txt@ as output. Arvados automatically collates theses files into a single collection, which is the output of the job:
~/you/crunch_scripts$ arv keep ls e2ccd204bca37c77c0ba59fc470cd0f7+162
-md5sum.txt
-md5sum.txt
-md5sum.txt
+./md5sum.txt
 ~/you/crunch_scripts$ arv keep get e2ccd204bca37c77c0ba59fc470cd0f7+162/md5sum.txt
 0f1d6bcf55c34bed7f92a805d2d89bbf alice.txt
 504938460ef369cd275e4ef58994cffe bob.txt