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 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Ind
 [Top of Book]  [Contents]   [Previous Chapter]   [Next Chapter] 

36 Parallel Computation - Core Functions

36 Parallel Computation - Core Functions

ChildProcess() ChildProcess("computer.ac.wales") ChildProcess(["-m", "100000M", "-T"]) ChildProcess("computer.ac.wales", ["-m", "100000M", "-T"])

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: 1) the address of a remote computer for which ssh has been configured to require no password from the user; (2) or a list of GAP command line options; (3) or the address of a computer followed by a list of command line options.

(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]  [Contents]   [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 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Ind

generated by GAPDoc2HTML