Asir: 7.5 Functions for distributed computation

7.5 Functions for distributed computation

7.5.1 `ox_launch`, `ox_launch_nox`, `ox_shutdown`

ox_launch([host[,dir],command])
ox_launch_nox([host[,dir],command]): :: Initialize OpenXM servers.
ox_shutdown(id): :: Terminates OpenXM servers.

return: integer
host: string or 0
dir command: string
id: integer

Function ox_launch() invokes a process to execute command on a host host and enables Asir to communicate with that process. If the number of arguments is 3, ‘ox_launch’ in dir is invoked on host. Then ‘ox_launch’ invokes command. If host is equal to 0, all the commands are invoked on the same machine as the Asir is running. If no arguments are specified, host, dir and command are regarded as 0, the value of get_rootdir() and ‘ox_asir’ in the same directory respectively.
If host is equal to 0, then dir can be omitted. In such a case dir is regarded as the value of get_rootdir().
If command begins with ‘/’, it is regarded as an absolute pathname. Otherwise it is regarded as a relative pathname from dir.
On UNIX, ox_launch() invokes ‘xterm’ to display standard outputs from command. If X11 is not available or one wants to invoke servers without ‘xterm’, use ox_launch_nox(), where the outputs of command are redirected to ‘/dev/null’. If the environment variable DISPLAY is not set, ox_launch() and ox_launch_nox() behave identically.
The returned value is used as the identifier for communication.
The peers communicating with Asir are not necessarily processes running on the same machine. The communication will be successful even if the byte order is different from those of the peer processes, because the byte order for the communication is determined by a negotiation between a client and a server.
The following preparations are necessary. Here, Let A be the host on which Asir is running, and B the host on which the peer process will run.
1. Register the hostname of the host A to the ‘~/.rhosts’ of the host B. That is, you should be allowed to access the host B from A without supplying a password.
2. For cases where connection to X is also used, let Xserver authorize the relevant hosts. Adding the hosts can be done by command xhost.
3. If an environment variable ASIR_RSH is set, the content of this variable is used as a promgram to invoke remote servers instead of rsh. For example,
```
% setenv ASIR_RSH "ssh -f -X -A "
```
  implies that remote servers are invoked by ‘ssh’ and that X11 forwarding is enabled. See the manual of ‘ssh’ for the detail.
4. Some command’s consume much stack space. You are recommended to set the stack size to about 16MB large in ‘.cshrc’ for safe. To specify the size, put limit stacksize 16m for an example.
When command opens a window on X, it uses the string specified for display; if the specification is omitted, it uses the value set for the environment variable DISPLAY.
ox_shutdown() terminates OpenXM servers whose identifier is id.
When Asir is terminated successfully, all I/O streams are automatically closed, and all the processes invoked are also terminated. However, some remote processes may not terminated when Asir is terminated abnormally. If ever Asir is terminated abnormally, you have to kill all the unterminated process invoked by Asir on every remote host. Check by ps command on the remote hosts to see if such processed are alive.
‘xterm’ for displaying the outputs from command is invoked with ‘-name ox_term’ option. Thus, by specifying resources for the resource name ‘ox_term’, only the behaviour of the ‘xterm’ can be customized.
```
/* iconify on start */
ox_xterm*iconic:on 
/* activate the scroll bar */
ox_xterm*scrollBar:on
/* 1000 lines can be shown by the scrollbar */
ox_xterm*saveLines:1000
```

[219] ox_launch();
0
[220] ox_rpc(0,"fctr",x^10-y^10);      
0
[221] ox_pop_local(0);
[[1,1],[x^4+y*x^3+y^2*x^2+y^3*x+y^4,1],
[x^4-y*x^3+y^2*x^2-y^3*x+y^4,1],[x-y,1],[x+y,1]]
[222] ox_shutdown(0);    
0

References: ox_rpc, ox_cmo_rpc, ox_execute_string, ox_pop_cmo, ox_pop_local, ifplot, conplot, plot, polarplot, plotover

7.5.2 `ox_launch_generic`

ox_launch_generic(host,launch,server,use_unix,use_ssh,use_x,conn_to_serv): :: Initialize OpenXM servers.

return: integer
host: string or 0
launcher server: string
use_unix use_ssh use_x conn_to_serv: integer

ox_launch_generic() invokes a control process launch and a server process server on host. The other arguments are switches for protocol family selection, on/off of the X environment, method of process invocation and selection of connection type.
If host is equal to 0, processes are invoked on the same machine as the Asir is running. In this case UNIX internal protocol is always used.
If use_unix is equal to 1, UNIX internal protocol is used. If use_unix is equal to 0, Internet protocol is used.
If use_ssh is equal to 1,‘ssh’ (Secure Shell) is used to invoke processes. If one does not use ‘ssh-agent’, a password (passphrase) is required. If ‘sshd’ is not running on the target machine, ‘rsh’ is used instead. But it will immediately fail if a password is required.
If use_x is equal to 1, it is assumed that X environment is available. In such a case server is invoked under ‘xterm’ by using the current DISPLAY variable. If DISPLAY is not set, it is invoked without X. Note that the processes will hang up if DISPLAY is incorrectly set.
If conn_to_serv is equal to 1, Asir (client) executes bind and listen, and the invoked processes execute connect. If conn_to_serv is equal to 0, Asir (client) the invoked processes execute bind and listen, and the client executes connect.

[342] LIB=get_rootdir();
/export/home/noro/ca/Kobe/build/OpenXM/lib/asir
[343] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",0,0,0,0);
1
[344] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",1,0,0,0);
2
[345] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",1,1,0,0);
3
[346] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",1,1,1,0);
4
[347] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",1,1,1,1);
5
[348] ox_launch_generic(0,LIB+"/ox_launch",LIB+"/ox_asir",1,1,0,1);
6

References: ox_launch, ox_launch_nox, ox_shutdown, ox_launch_generic

7.5.3 `generate_port`, `try_bind_listen`, `try_connect`, `try_accept`, `register_server`

generate_port([use_unix]): :: Generates a port number.
try_bind_listen(port): :: Binds and listens on a port.
try_connect(host,port): :: Connects to a port.
try_accept(socket,port): :: Accepts a connection request.
register_server(control_socket,control_port,server_socket,server_port): :: Registers the sockets for which connections are established.

return: integer or string for generate_port(), integer for the others
use_unix: 0 or 1
host: string
port control_port server_port: integer or string
socket control_socket server_socket: integer

These functions are primitives to establish communications between a client and servers.
generate_port() generates a port name for communication. If the argument is not specified or equal to 0, a port number for Internet domain socket is generated randomly. Otherwise a file name for UNIX domain (host-internal protocol) is generated. Note that it is not assured that the generated port is not in use.
try_bind_listen() creates a socket according to the protocol family indicated by the given port and executes bind and listen. It returns a socket identifier if it is successful. -1 indicates an error.
try_connect() tries to connect to a port port on a host host. It returns a socket identifier if it is successful. -1 indicates an error.
try_accept() accepts a connection request to a socket socket. It returns a new socket identifier if it is successful. -1 indicates an error. In any case socket is automatically closed. port is specified to distinguish the protocol family of socket.
register_server() registers a pair of a control socket and a server socket. A process identifier indicating the pair is returned. The process identifier is used as an argument of ox functions such as ox_push_cmo().
Servers are invoked by using shell(), or manually.

[340] CPort=generate_port();
39896
[341] SPort=generate_port();
37222
[342] CSocket=try_bind_listen(CPort);
3
[343] SSocket=try_bind_listen(SPort);
5

/*
ox_launch is invoked here :
%  ox_launch "127.1" 0 39716 37043 ox_asir "shio:0"
*/

[344] CSocket=try_accept(CSocket,CPort);
6
[345] SSocket=try_accept(SSocket,SPort);  
3
[346] register_server(CSocket,CPort,SSocket,SPort);
0

References: ox_launch, ox_launch_nox, ox_shutdown, ox_launch_generic, shell, ox_push_cmo, ox_push_local

7.5.4 ‘`ox_asir`’

‘ox_asir’ provides almost all the functionalities of Asir as an OpenXM server. ‘ox_asir’ is invoked by ox_launch or ox_launch_nox. If X environment is not available or is not necessary, one can use ox_launch_nox.

[5] ox_launch();
0

[5] ox_launch_nox("127.0.0.1","/usr/local/lib/asir",
"/usr/local/lib/asir/ox_asir");
0

[7] RemoteLibDir = "/usr/local/lib/asir/"$
[8] Machines = ["sumire","rokkaku","genkotsu","shinpuku"];
[sumire,rokkaku,genkotsu,shinpuku]
[9] Servers = map(ox_launch,Machines,RemoteLibDir,
RemoteLibDir+"ox_asir");
[0,1,2,3]

References: ox_launch, ox_launch_nox, ox_shutdown

7.5.5 `ox_rpc`, `ox_cmo_rpc`, `ox_execute_string`

ox_rpc(number,"func",arg0,...)
ox_cmo_rpc(number,"func",arg0,...)
ox_execute_string(number,"command",...): :: Calls a function on an OpenXM server

return: 0
number: integer (process identifier)
func: function name
command: string
arg0 ...: arbitrary (arguments)

Calls a function on an OpenXM server whose identifier is number.
It returns 0 immediately. It does not wait the termination of the function call.
ox_rpc() can be used when the server is ‘ox_asir’. Otherwise ox_cmo_rpc() should be used.
The result of the function call is put on the stack of the server. It can be received by ox_pop_local() or ox_pop_cmo().
If the server is not ‘ox_asir’, only data defined in OpenXM can be sent.
ox_execute_string requests the server to parse and execute command by the parser and the evaluater of the server. The result is pushed to the stack.

[234] ox_cmo_rpc(0,"dp_ht",dp_ptod((x+y)^10,[x,y]));
0
[235] ox_pop_cmo(0);
(1)*<<10,0>>
[236] ox_execute_string(0,"12345 % 678;");
0
[237] ox_pop_cmo(0);
141

References: ox_pop_cmo, ox_pop_local

7.5.6 `ox_reset`,`ox_intr`,`register_handler`

ox_reset(number): :: Resets an OpenXM server
ox_intr(number): :: Sends SIGINT to an OpenXM server
register_handler(func): :: Registers a function callable on a keyboard interrupt.

return: 1
number: integer(process identifier)
func: functor or 0

ox_reset() resets a process whose identifier is number. After its execution the process is ready for receiving data.
After executing ox_reset(), sending/receiving buffers and stream buffers are assured to be empty.
Even if a process is running, the execution is safely stopped.
ox_reset() may be used prior to a distirbuted computation. It can be also used to interrupt a distributed computation.
ox_intr() sends SIGINT to a process whose identifier is number. The action of a server against SIGINT is not specified in OpenXM. ‘ox_asir’ immediately enters the debug mode and pops up an window to input debug commands on X window system.
register_handler() registers a function func(). If u is specified on a keybord interrupt, func() is executed before returning the toplevel. If ox_reset() calls are included in func(), one can automatically reset OpenXM servers on a keyboard interrupt.
If func is equal to 0, the setting is reset.

[10] ox_launch();
0
[11] ox_rpc(0,"fctr",x^100-y^100);
0
[12] ox_reset(0); /* usr1 : return to toplevel by SIGUSR1 */
1                 /* is displayed on the xterm.           */

[340] Procs=[ox_launch(),ox_launch()];
[0,1]
[341] def reset() { extern Procs; map(ox_reset,Procs);}
[342] map(ox_rpc,Procs,"fctr",x^100-y^100);
[0,0]
[343] register_handler(reset);
1
[344] interrupt ?(q/t/c/d/u/w/?) u
Abort this computation? (y or n) y
Calling the registered exception handler...done.
return to toplevel

References: ox_rpc, ox_cmo_rpc, ox_execute_string

7.5.7 `ox_push_cmo`, `ox_push_local`

ox_push_cmo(number,obj)
ox_push_local(number,obj): :: Sends obj to a process whose identifier is number.

return: 0
number: integer(process identifier)
obj: object

Sends obj to a process whose identifier is number.
ox_push_cmo is used to send data to an Open_XM other than ‘ox_asir’ and ‘ox_plot’.
ox_push_local is used to send data to ‘ox_asir’ and ‘ox_plot’.
The call immediately returns unless the stream buffer is full.

References: ox_rpc, ox_cmo_rpc, ox_execute_string, ox_pop_cmo, ox_pop_local

7.5.8 `ox_pop_cmo`, `ox_pop_local`

ox_pop_local(number): :: Receives data from a process whose identifier is number.

return: received data
number: integer(process identifier)

Receives data from a process whose identifier is number.
ox_pop_cmo can be used to receive data form an OpenXM server other than ‘ox_asir’ and ‘ox_plot’.
ox_pop_local can be used to receive data from ‘ox_asir’, ‘ox_plot’.
If no data is available, these functions block. To avoid it, send SM_popCMO (262) or SM_popSerializedLocalObject (258). Then check the process status by ox_select. Finally call ox_get for a ready process.

[341] ox_cmo_rpc(0,"fctr",x^2-1);
0
[342] ox_pop_cmo(0);
[[1,1],[x-1,1],[x+1,1]]
[343] ox_cmo_rpc(0,"newvect",3);
0
[344] ox_pop_cmo(0);
error([41,cannot convert to CMO object])
[345] ox_pop_local(0);
[ 0 0 0 ]

References: ox_rpc, ox_cmo_rpc, ox_execute_string, ox_push_cmd, ox_sync, ox_select, ox_get

7.5.9 `ox_push_cmd`, `ox_sync`

ox_push_cmd(number,command): :: Sends a command command to a process whose identifier is number.
ox_sync(number): :: Sends OX_SYNC_BALL to a process whose identifier is number.

return: 0
number: integer(process identifier)
command: integer(command identifier)

Sends a command or OX_SYNC_BALL to a process whose identifier is number.
Data in OpenXM are categorized into three types: OX_DATA, OX_COMMAND, OX_SYNC_BALL. Usually OX_COMMAND and OX_SYNC_BALL are sent implicitly with high level operations, but these functions are prepared to send these data explicitly.
OX_SYNC_BALL is used on the reseting operation by ox_reset. Usually OX_SYNC_BALL will be ignored by the peer.

[3] ox_rpc(0,"fctr",x^100-y^100);
0
[4] ox_push_cmd(0,258);
0
[5] ox_select([0]);
[0]
[6] ox_get(0);
[[1,1],[x^2+y^2,1],[x^4-y*x^3+y^2*x^2-y^3*x+y^4,1],...]

References: ox_rpc, ox_cmo_rpc, ox_execute_string, ox_reset,ox_intr,register_handler

7.5.10 `ox_get`

ox_get(number): :: Receives data form a process whose identifer is number.

return
number: integer(process identifier)

Receives data form a process whose identifer is number.
One may use this function with ox_push_cmd.
ox_pop_cmo and ox_pop_local is realized as combinations of ox_push_cmd and ox_get.

[11] ox_push_cmo(0,123);
0
[12] ox_push_cmd(0,262); /* 262=OX_popCMO */
0
[13] ox_get(0);
123

References: ox_pop_cmo, ox_pop_local, ox_push_cmd, ox_sync

7.5.11 `ox_pops`

ox_pops(number[,nitem]): :: Removes data form the stack of a process whose identifier is number.

return: 0
number: integer(process identifier)
nitem: non-negative integer

Removes data form the stack of a process whose identifier is number. If nitem is specified, nitem items are removed. If nitem is not specified, 1 item is removed.

[69] for(I=1;I<=10;I++)ox_push_cmo(0,I);
[70] ox_pops(0,4);  
0
[71] ox_pop_cmo(0);
6

References: ox_pop_cmo, ox_pop_local

7.5.12 `ox_select`

ox_select(nlist[,timeout]): :: Returns the list of process identifiers on which data is available.

return: list
nlist: list of integers (process identifier)
timeout: number

Returns the list of process identifiers on which data is available.
If all the processes in nlist are running, it blocks until one of the processes returns data. If timeout is specified, it waits for only timeout seconds.
By sending SM_popCMO or SM_popSerializedLocalObject with ox_push_cmd() in advance and by examining the process status with ox_select(), one can avoid a hanging up caused by ox_pop_local() or ox_pop_cmo(). In such a case, data can be received by ox_get().

ox_launch();
0
[220] ox_launch();
1
[221] ox_launch();
2
[222] ox_rpc(2,"fctr",x^500-y^500);
0
[223] ox_rpc(1,"fctr",x^100-y^100);
0
[224] ox_rpc(0,"fctr",x^10-y^10);  
0
[225] P=[0,1,2];
[0,1,2]
[226] map(ox_push_cmd,P,258);
[0,0,0]
[227] ox_select(P);
[0]
[228] ox_get(0);   
[[1,1],[x^4+y*x^3+y^2*x^2+y^3*x+y^4,1],
[x^4-y*x^3+y^2*x^2-y^3*x+y^4,1],[x-y,1],[x+y,1]]

References: ox_pop_cmo, ox_pop_local, ox_push_cmd, ox_sync, ox_get

7.5.13 `ox_flush`

ox_flush(id): :: Flushes the sending buffer.

return: 1
id: process identifier

By default the batch mode is off and the sending buffer is flushed at every sending operation of data and command.
The batch mode is set by "ox_batch" switch of "ctrl".
If one wants to send many pieces of small data, ctrl("ox_batch",1) may decrease the overhead of flush operations. Of course, one has to call ox_flush(id) at the end of the sending operations.
Functions such as ox_pop_cmo and ox_pop_local enter a waiting mode immediately after sending a command. These functions always flush the sending buffer.

[340] ox_launch_nox();
0
[341] cputime(1);
0
7e-05sec + gc : 4.8e-05sec(0.000119sec)
[342] for(I=0;I<10000;I++)ox_push_cmo(0,I);
0.232sec + gc : 0.006821sec(0.6878sec)
[343] ctrl("ox_batch",1);
1
4.5e-05sec(3.302e-05sec)
[344] for(I=0;I<10000;I++)ox_push_cmo(0,I); ox_flush(0);
0.08063sec + gc : 0.06388sec(0.4408sec)
[345] 1
9.6e-05sec(0.01317sec)

References: ox_pop_cmo, ox_pop_local, ctrl

7.5.14 `ox_get_serverinfo`

ox_get_serverinfo([id]): :: Gets server’s mathcap and proess id.

return: list
id: process identifier

If id is specified, the mathcap of the process whose identifier is id is returned.
If id is not specified, the list of [id,Mathcap] is returned, where id is the identifier of a currently active process, and Mathcap is the mathcap of the process. identifier id is returned.

[343] ox_get_serverinfo(0);
[[199909080,Ox_system=ox_sm1.plain,Version=2.991118,HOSTTYPE=FreeBSD],
[262,263,264,265,266,268,269,272,273,275,276],
[[514],[2130706434,1,2,4,5,17,19,20,22,23,24,25,26,30,31,60,61,27,
33,40,16,34]]]
[344] ox_get_serverinfo(); 
[[0,[[199909080,Ox_system=ox_sm1.plain,Version=2.991118,
HOSTTYPE=FreeBSD],
[262,263,264,265,266,268,269,272,273,275,276],
[[514],[2130706434,1,2,4,5,17,19,20,22,23,24,25,26,30,31,60,61,27,33,
40,16,34]]]],
[1,[[199901160,ox_asir],
[276,275,258,262,263,266,267,268,274,269,272,265,264,273,300,270,271],
[[514,2144202544],
[1,2,3,4,5,2130706433,2130706434,17,19,20,21,22,24,25,26,31,27,33,60],
[0,1]]]]]

References: Mathcap.

7.5.15 `ifplot`, `conplot`, `plot`, `polarplot`, `plotover`

ifplot(func [,geometry] [,xrange] [,yrange] [,id] [,name]): :: Displays real zeros of a bi-variate function.
conplot(func [,geometry] [,xrange] [,yrange] [,zrange] [,id] [,name]): :: Displays real contour lines of a bi-variate function.
plot(func [,geometry] [,xrange] [,id] [,name]): :: Displays the graph of a univariate function.
polarplot(func [,geometry] [,thetarange] [,id] [,name]): :: Displays the graph of a curve given in polar form.
plotover(func,id,number): Plots on the existing window real zeros of a bivariate function.

return: integer
func: polynomial
geometry xrange yrange zrange: list
id number: integer
name: string

Function ifplot() draws a graph of real zeros of a bi-variate function. Function conplot() plots the contour lines for a same argument. Function plot() draws the graph of a uninivariate function. Function polarplot() draws the graph of a curve given in polar form r=f(theta).
The plotting functions are realized by an OpenXM server. On UNIX it is ‘ox_plot’ in Asir root directory. On Windows ‘engine’ acts as ‘ox_plot’. Of course, it must be activated by ox_launch() ox_launch_nox(). If the identifier of an active ‘ox_plot’ is specified as id, the server is used for drawing pictures. If id is not specified, an available ‘ox_plot’ server is used if it exists. If no ‘ox_plot’ server is available, then ox_launch_nox() is automatically executed to invoke ‘ox_plot’.
Argument func is indispensable. Other arguments are optional. The format of optional arguments and their default values (parenthesized) are listed below.

geometry

Window size is specified by [x,y] in unit ‘dot.’ [300,300] for UNIX version;

xrange yrange

Value ranges of the variables are specified by [v,vmin,vmax]. ([v,-2,2] for each variable.) If this specification is omitted, the indeterminate having the higher order in func is taken for ‘x’ and the one with lower order is taken for ‘y’. To change this selection, specify explicitly by xrange and/or yrange. For an uni-variate function, the specification is mandatory.

zrange

This specification applies only to conplot(). The format is [v,vmin,vmax [,step ]]. If step is specified, the height difference of contours is set to (vmax-vmin)/step. ([z,-2,2,16].)

id

This specifies the number of the remote process by which you wish to draw a graph. (The number for the newest active process.)

name

The name of the window. (Plot.) The created window is titled name:n/m which means the m-th window of the process with process number n. These numbers are used for plotover().
The maximum number of the windows that can be created on a process is 128.
Function plotover() superposes reals zeros of its argument bi-variate function onto the specified window.
Enlarged plot can be obtained for rectangular area which is specified, on an already existing window with a graph, by dragging cursor with the left button of mouse from the upper-left corner to lower-right corner and then releasing it. Then, a new window is created whose shape is similar to the specified area and whose size is determined so that the largest side of the new window has the same size of the largest side of the original window. If you wish to cancel the action, drag the cursor to any point above or left of the starting point.
This facility is effective when precise button switch is inactive. If precise is selected and active, the area specified by the cursor dragging will be rewritten on the same window. This will be explained later.
A click of the right button will display the current coordinates of the cursor at the bottom area of the window.
Place the cursor at any point in the right marker area on a window created by conplot(), and drag the cursor with the middle mutton. Then you will find the contour lines changing their colors depending on the movement of the cursor and the corresponding height level displayed on the upper right corner of the window.
Several operations are available on the window: by button operations for UNIX version, and pull-down menus for Windows version.

quit

Destroys (kills) the window. While computing, quit the current computation. If one wants to interrupt the computation, use ox_reset().

wide (toggle)

Will display, on the same window, a new area enlarged by 10 times as large as the current area for both width-direction and height-direction. The current area will be indicated by a rectangle placed at the center. Area specification by dragging the cursor will create a new window with a plot of the graph in the specified area.

precise (toggle)

When selected and active, ox_plot redraws the specified area more precisely by integer arithmetic. This mode uses bisection method based on Sturm sequence computation to locate real zeros precisely. More precise plotting can be expected by this technique than by the default plotting technique, at the expense of significant increase of computing time. As you see by above explanation, this function is only effective to polynomials with rational coefficients. (Check how they differ for (x^2+y^2-1)^2.)

formula

Displays the expression for the graph.

noaxis (toggle)

Erase the coordinates.
Program ‘ox_plot’ may consume much stack space depending on which machine it is running. You are recommended to set the stack size to about 16MB as large in ‘.cshrc’ for safe. To specify the size, put limit stacksize 16m for an example.

You can customize various resources of a window on X, e.g., coloring, shape of buttons etc. The default setting of resources is shown below. For plot*form*shapeStyle you can select among rectangle, oval, ellipse, and roundedRectangle.

plot*background:white
plot*form*shapeStyle:rectangle
plot*form*background:white
plot*form*quit*background:white
plot*form*wide*background:white
plot*form*precise*background:white
plot*form*formula*background:white
plot*form*noaxis*background:white
plot*form*xcoord*background:white
plot*form*ycoord*background:white
plot*form*level*background:white
plot*form*xdone*background:white
plot*form*ydone*background:white

References: ox_launch, ox_launch_nox, ox_shutdown, ox_reset,ox_intr,register_handler

7.5.16 `open_canvas`, `clear_canvas`, `draw_obj`, `draw_string`

open_canvas(id[,geometry]): :: Opens a canvas, which is a window for drawing objects.
clear_canvas(id,index): :: Clears a canvas.
draw_obj(id,index,pointorsegment [,color]): :: Draws a point or a line segment on a canvas.
draw_string(id,index,[x,y],string [,color]): :: Draws a character string on a canvas.

return: 0
id index color x y: integer
pointorsegment: list
string: character string

These functions are supplied by the OpenXM server ‘ox_plot’ (‘engine’ on Windows).
open_canvas opens a canvas, which is a window for drawing objecgts. One can specifies the size of a canvas in pixel by supplying geometry option [x,y]. The default size is [300,300]. This function pushes an integer value onto the stack of the OpenXM server. The value is used to distiguish the opened canvas and one has to pop and maintain the value by ox_pop_cmo for subsequent calls of draw_obj.
clear_canvas clears a canvas specified by a server id id and a canvas id index.
draw_obj draws a point or a line segment on a canvas specified by a server id id and a canvas id index. If pointorsegment is [x,y], it is regarded as a point. If pointorsegment is [x,y,u,v], it is regarded as a line segment which connects [x,y] and [u,v]. If color is specified, color/65536 mod 256, color/256 mod 256, color mod 256 are regarded as the vaules of Red, Green, Blue (Max. 255) respectively.
draw_string draws a character string string on a canvas specified by a server id id and a canvas id index. The position of the string is specified by [x,y].

[182] Id=ox_launch_nox(0,"ox_plot");
0
[183] open_canvas(Id);
0
[184] Ind=ox_pop_cmo(Id);
0
[185] draw_obj(Id,Ind,[100,100]);
0
[186] draw_obj(Id,Ind,[200,200],0xffff);
0
[187] draw_obj(Id,Ind,[10,10,50,50],0xff00ff);
0
[187] draw_string(Id,Ind,[100,50],"hello",0xffff00);
0
[189] clear_canvas(Id,Ind);
0

References: ox_launch, ox_launch_nox, ox_shutdown, ox_reset,ox_intr,register_handler, ox_pop_cmo, ox_pop_local.

This document was generated on April 20, 2024 using texi2html 5.0.

7.5.1 `ox_launch`, `ox_launch_nox`, `ox_shutdown`
7.5.2 `ox_launch_generic`
7.5.4 ‘`ox_asir`’
7.5.5 `ox_rpc`, `ox_cmo_rpc`, `ox_execute_string`
7.5.7 `ox_push_cmo`, `ox_push_local`
7.5.8 `ox_pop_cmo`, `ox_pop_local`
7.5.9 `ox_push_cmd`, `ox_sync`
7.5.10 `ox_get`
7.5.11 `ox_pops`
7.5.6 `ox_reset`,`ox_intr`,`register_handler`
7.5.12 `ox_select`
7.5.13 `ox_flush`
7.5.14 `ox_get_serverinfo`
7.5.3 `generate_port`, `try_bind_listen`, `try_connect`, `try_accept`, `register_server`
7.5.15 `ifplot`, `conplot`, `plot`, `polarplot`, `plotover`
7.5.16 `open_canvas`, `clear_canvas`, `draw_obj`, `draw_string`

7.5 Functions for distributed computation

7.5.1 ox_launch, ox_launch_nox, ox_shutdown

7.5.2 ox_launch_generic

7.5.3 generate_port, try_bind_listen, try_connect, try_accept, register_server

7.5.4 ‘ox_asir’

7.5.5 ox_rpc, ox_cmo_rpc, ox_execute_string

7.5.6 ox_reset,ox_intr,register_handler

7.5.7 ox_push_cmo, ox_push_local

7.5.8 ox_pop_cmo, ox_pop_local

7.5.9 ox_push_cmd, ox_sync

7.5.10 ox_get

7.5.11 ox_pops

7.5.12 ox_select

7.5.13 ox_flush

7.5.14 ox_get_serverinfo

7.5.15 ifplot, conplot, plot, polarplot, plotover

7.5.16 open_canvas, clear_canvas, draw_obj, draw_string