matlab: RunOpenEMS can search a list for a free host using FindFreeSSH

matlab/FindFreeSSH.m

@@ -0,0 +1,55 @@
+function host = FindFreeSSH(host_list, wait_time, command)
+% function host = FindFreeSSH(host_list, wait_time, command)
+% 
+% Find a free ssh host not running openEMS
+% 
+% internal function used by RunOpenEMS
+% 
+% host_list: give a list of possible host
+% 
+% wait_time: wait x seconds after not finding a free host and rechecking
+%            default: 60 seconds
+% 
+% command: unix command to check for free host (empty result --> free)
+%          default: 'ps -ewwo user,args | grep openEMS'
+%
+% See also RunOpenEMS
+%
+% openEMS matlab interface
+% -----------------------
+% author: Thorsten Liebig
+
+if (nargin<3)
+    % command which should return an empty string if host is available
+    command = 'ps -e user,args | grep openEMS';
+end
+
+if (nargin<2)
+    wait_time = 60;
+end
+
+while 1
+    
+    for n = 1:numel(host_list)
+        host = host_list{n};
+        [status, result] = unix(['ssh ' host ' ' command]);
+        
+        if isempty(result)
+            disp(['FindFreeSSH:: found a free host: ' host ]);
+            return
+        else
+            disp(['FindFreeSSH:: ' host ' is busy running openEMS ... ' ]);
+        end
+
+    end
+    
+    host = '';
+    
+    if (wait_time<=0)
+        warning('openEMS:FindFreeSSH',' unable to find a free host ');
+        return
+    end
+    
+    disp([' no free host found waiting for ' num2str(wait_time) ' seconds ... '])
+    pause(wait_time)
+end

matlab/RunOpenEMS.m

@@ -12,6 +12,8 @@ function RunOpenEMS(Sim_Path, Sim_File, opts, Settings)
 % (ssh only on unix with working ssh client)
 % Settings.SSH.host = '<hostname or ip>'
 % Settings.SSH.bin = '<path_to_openEMS>/openEMS.sh'
+% ssh optional: 
+% Settings.SSH.host_list = {'list','of','hosts'}; %searches for a free host
 %
 % optional MPI:
 % Settings.MPI.xxx --> help RunOpenEMS_MPI
@@ -21,7 +23,7 @@ function RunOpenEMS(Sim_Path, Sim_File, opts, Settings)
 %
 % RunOpenEMS(Sim_Path,Sim_File,opts,Settings)
 %
-% See also WriteOpenEMS
+% See also WriteOpenEMS FindFreeSSH
 %
 % openEMS matlab interface
 % -----------------------
@@ -51,6 +53,15 @@ if (isfield(Settings,'SSH') && isunix)
     scp_options = '-C -o "PasswordAuthentication no" -o "StrictHostKeyChecking no"';
     ssh_options = [scp_options ' -x'];
     
+    if isfield(Settings.SSH,'host_list')
+        host = FindFreeSSH(Settings.SSH.host_list);
+        if ~isempty(host)
+            Settings.SSH.host = host;
+        else
+            error('openEMS:RunOpenEMS', 'unable to find host, abort openEMS');
+        end
+    end
+    
     % create a tmp working dir
  	[status, result] = unix(['ssh ' ssh_options ' ' Settings.SSH.host ' "mktemp -d /tmp/openEMS_XXXXXXXXXXXX"']);
     if (status~=0)