Reservation between two users - centos

I have two user u1 and u2 and 4 nodes.
I would like to know how to create a reservation for u2 to take only 1 node. But if u1 wants to use the 4 nodes and they are available (if u2 is not using a node), he can take them.
I tried that but it does not do everything I want:
scontrol create reservation StartTime=now Duration=infinite NodeCnt=1 User=u2
I think we have to use the partition option but I do not really understand how to use it.

A possible solution is to use partitions.
Since there are quite a lot of steps, which may depend on your specific configuration, I link the official quickstart documentation for slurm admins: https://slurm.schedmd.com/quickstart_admin.html

Related

How to properly use spmd in matlab with handle classes and synchonize data between workers

my problem is following:
I have a handle class with many objects and I want to link them to each other.
So my vertex(1) from my class vertex needs to be linked to vertex(2) and vertex(3), so that my vertex(1) has the properties vertex(1).neighboor_vertex=vertex(2) (and vertex(3)).
This is just one thing that has to be done (actually I need to link and relink different classes to each other and because its millions of objects and want to do it in parrallel and the fact that linking is not working in parallel stops me from following steps).
So while worker 1 links vertex(1) to vertex(2), no other worker should be able to change the properties of both, they can lets say link 5 to 7 or so, and when the linking is done the new link of vertex(1) to vertex(2) and vertex(2) to vertex(1), needs to be updates to all other workers, so that when another worker wants to link vertex(3) to vertex(1), it has to know that it is alreay linked to vertex(1), otherwise there would be 2 different versions of vertex(1), one linked to vertex(2) and one linked to vertex(3).
So for the blocking that multiple workers cant change the the vertex I would need something like a mutex within the spmd, otherwise it wouldnt be threatsave...
What would be the best way to do this in Matlab?
Many Thanks in advance
Best regards

looking best notation for UML Class diagram

I have the following problem to resolv. Given the following UML diagram:
I need to complete the diagram doing the following steps:
a) When an employee has a skill, the relationship between the employee and the skill shows years of experience.
b) A worker may have another employee as a manager and a worker who is a manager must manage five or more workers. As a manager, you can determine which workers he manages, but a worker can not determine who is his manager.
c) An activity can have a maximum activity precedent and any number of upcoming activities. Using these roles, we can show how the activities are arranged. Given an activity, you can only determine their own activities (if you have), but not what your previous activity (if any).
d) A worker is not simply associated with a set of skills, but a worker has skills. In particular, every worker should have three or more skills, and any number of employees can have the same ability.
e) A project is not simply a set of activities associated with, but contains a project activities. Specifically, a project must have one or more activities, and activity must belong to exactly one project.
f) Projects and activities are a specific type of job.
My solution is shown in the following picture, but because I am new in this I would like to check if is fine.
Thank you in advance!
Looks good in most parts. Honestly I don't understand the later parts of c)
Your -boss relation is wrong. Your Northern Koreans should not have a private known boss. Instead there's only the other way around and the boss has - let's call them - -slaves. If you put in a private -boss it actually means that the slave can navigate to its private boss which is explicitly not wanted. Only the boss shall know the one he's responsible for. So actually the object itself is the boss object. As a thought, since only the boss should have those 5 employees, it could be an idea to create a separate boss object like this:
Note that this might also have drawbacks since Boss is now actually a different object than Employee, but it seems to fit the requirements.
Point f) seems to call for a generalization. So you would need a generalization towards SpecificJob. This would be an arrow with open triangle, not the one you used:
This actually reads Project and Activity are specific kinds of Job as they both inherit from the latter.

some questions about designing on OrientDB

We were looking for the most suitable database for our innovative “collaboration application”. Sorry, we don’t know how to name it in a way generally understood. In fact, highly complicated relationships among tenants, roles, users, tasks and bills need to be handled effectively.
After reading 5 DBs(Postgrel, Mongo, Couch, Arango and Neo4J), when the words “… relationships among things are more important than things themselves” came to my eyes, I made up my mind to dig into OrientDB. Both the design philosophy and innovative features of OrientDB (multi-models, cluster, OO,native graph, full graph API, SQL-like, LiveQuery, multi-masters, auditing, simple RID and version number ...) keep intensifying my enthusiasm.
OrientDB enlightens me to re-think and try to model from a totally different viewpoint!
We are now designing the data structure based on OrientDB. However, there are some questions puzzling me.
LINK vs. EDGE
Take a case that a CLIENT may place thousands of ORDERs, how to choose between LINKs and EDGEs to store the relationships? I prefer EDGEs, but they seem like to store thousands of RIDs of ORDERs in the CLIENT record.
Embedded records’ Security
Can an embedded record be authorized independently from it’s container record?
Record-level Security
How does activating Record-level Security affect the query performance?
Hope I express clearly. Any words will be truly appreciated.
LINK vs EDGE
If you don't have properties on your arch you can use a link, instead if you have it use edges. You really need edges if you need to traverse the relationship in both directions, while using the linklist you can only in one direction (just like a hyperlink on the web), without the overhead of edges. Edges are the right choice if you need to walk thru a graph.Edges require more storage space than a linklist. Another difference between them it's the fact that if you have two vertices linked each other through a link A --> (link) B if you delete B, the link doesn't disappear it will remain but without pointing something. It is designed this way because when you delete a document, finding all the other documents that link to it would mean doing a full scan of the database, that typically takes ages to complete. The Graph API, with bi-directional links, is specifically designed to resolve this problem, so in general we suggest customers to use that, or to be careful and manage link consistency at application level.
RECORD - LEVEL SECURITY
Using 1 Million vertex and an admin user called Luke, doing a query like: select from where title = ? with an NOT_UNIQUE_HASH_INDEX the execution time it has been 0.027 sec.
OrientDB has the concept of users and roles, as well as Record Level Security. It also supports token based authentication, so it's possible to use OrientDB as your primary means of authorizing/authenticating users.
EMBEDDED RECORD'S SECURITY
I've made this example for trying to answer to your question
I have this structure:
If I want to access to the embedded data, I have to do this command: select prop from User
Because if I try to access it through the class that contains the type of car I won't have any type of result
select from Car
UPDATE
OrientDB supports that kind of authorization/authentication but it's a little bit different from your example. For example: if an user A, without admin permission, inserts a record, another user B can't see the record inserted by user A without admin permission. An User can see only the records that has inserted.
Hope it helps

how to add user and item metadata in recommendation engine and which python open source tool can give this features

Ex : i have a master file like
userid itemid rating
1 2 5
another user file, where user related metadata present, metadata could be many :
userid age
1 5
2 8
also i have a item file, where item related metadata present. meta data could be many
itemid item_catagory item_geo
1 5 india
if i will recommend any item to a user, i want to include these meta information.
i want to know whether matrix factorisation will be helpful and which python open source module has this kind of implementation available.
To include additional information to recommender system e.g. about an item, user or a recommendation event one of the existing methods for Context Aware Recommender System (CARS) can be applied.
Try starting with Factorization Machines. You can convert Your data to svmlight format and go with reference implementation libfm. It has the best documentation and there is a similar example where you can find how to prepare Your data. If it has to be Python, there are also many existing implementation, e.g. fastFM Simpler - pyFM. If You want to try Julia, maybe You can use my code of FactorizationMachines.jl as a base :-)
If You will be comfortable with standard FM, check out: LightFM and Field Aware FM
I think FM are one of the most successful and easy to use models for CARS. Please give some feedback how it works for You. If You need different approach I will be happy to help.

How to decide whether to use a RDBMS, Doc/Obj ODBMS or Graph?

What I intend to design basically boils down to a list of users, organisations, events, addresses and comments which could quite easily be maintained in a RDBMS such as MySQL. However, if the project takes off I want to add another aspect which is resources - i.e. files, videos, images etc which can belong to either a user, organisation or event. This instantly raises the question of whether to use a RDBMS and store a reference to an external file through a table related to each of the categories previously mentioned or whether to use a Doc/Obj ODBMS such as MongoDB to store these items.
But I also want to be able to link users, organisations and events. i.e. User A owns Org 1 and Org 2. User B owns Org 3 and Org 4. User C owns Org 5. Org 1 has an Event X, held at Addr M on Date R, which Org 3 will also be at. User C intends to attend Event X. Org 2 also has an Event Y at Addr M but on Date T. etc etc. As such, I would suspect that a Graph DBMS such as OrientDB would be the best solution. Either that, or I would have a lot of tables in a RDBMS with a lot of joins, and potentially a lot of queries, or a very strange structure in a Doc/Obj DBMS.
I've looked at InfoGrid, which is a Graph database that can connect to MySQL, which could be a potential way to skin this cat. Has anybody else attempted anything like this? What are your thoughts on how to implement such a system, which needs to be scalable? Suggestions are greatly appreciated.
Your description lends itself to a relational model. RDBMS for this particular setup is the proper way to go.