Goto Chapter: Top 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Ind
 Top of Book   Previous Chapter   Next Chapter 

21. Parallel Computation - Core Functions

21. Parallel Computation - Core Functions

ChildProcess()
ChildProcess("computer.ac.wales")

This starts a GAP session as a child process and returns a stream to the child process. If no argument is given then the child process is created on the local machine; otherwise the argument should be the address of a remote computer for which ssh has been configured to require no password from the user.

(To configure ssh so that the user can login without a password prompt from "thishost" to "remotehost" either consult "man ssh" or

- open a shell on thishost
- cd .ssh
- ls
-> if id_dsa, id_rsa etc exists, skip the next two steps!
- ssh-keygen -t rsa
- ssh-keygen -t dsa
- scp *.pub user@remotehost:~/
- ssh remotehost -l user
- cat id_rsa.pub >> .ssh/authorized_keys
- cat id_dsa.pub >> .ssh/authorized_keys
- rm id_rsa.pub id_dsa.pub
- exit

You should now be able to connect from "thishost" to "remotehost" without a password prompt.)

ChildClose(s)

This closes the stream s to a child GAP process.

ChildCommand("cmd;",s)

This runs a GAP command "cmd;" on the child process accessed by the stream s. Here "cmd;" is a string representing the command.

NextAvailableChild(L)

Inputs a list L of child processes and returns a child in L which is ready for computation (as soon as such a child is available).

IsAvailableChild(s)

Inputs a child process s and returns true if s is currently available for computations, and false otherwise.

ChildPut(A,"B",s)

This copies a GAP object A on the parent process to an object B on the child process s. (The copying relies on the function PrintObj(A); )

ChildGet("A",s)

This functions copies a GAP object A on the child process s and returns it on the parent process. (The copying relies on the function PrintObj(A); )

HAPPrintTo("file",R)

Inputs a name "file" of a new text file and a HAP object R. It writes the object R to "file". Currently this is only implemented for R equal to a resolution.

HAPRead("file",R)

Inputs a name "file" containing a HAP object R and returns the object. Currently this is only implemented for R equal to a resolution.


 


 Top of Book   Previous Chapter   Next Chapter 
Goto Chapter: Top 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Ind

generated by GAPDoc2HTML