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  • Is it safe to operate a laptop without battery?

    - by leladax
    I know it's 'unsafe' in terms of data loss but I noticed motherboards still have some of their circuits on power when they are plugged in [e.g. a circuit that must wait for power-on signals is certainly one of them]. Hence, I wondered if it would increase the life of the laptop if the battery was simply off. Let alone that may also increase battery life, but that's the least of my concerns. Notice the main point is to plug it off on hibernate and have no power source whatsoever for the duration of being off (apart from the clock battery). (i.e. saving having to plug off the battery every time)

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  • Public Folders - Delete Public Folders from 2003 after migrating to 2010 (via Adsiedit) - safe?

    - by HeavenCore
    Similar Question: How do I delete a public store in Exchange 2003? We are ready to remove our Exchange 2003 server after having migrated all public folders and mailboxes to 2010. We ran for a week with the exchange 2003 server shutdown and everything seemed to work. When I try to delete the PF database from 2003 it says it contains replicas. Whilst migrating i only had one was sync working (from 2003 to 2010) so i believe that 2003 hasn't received the responses from 2010 saying replica removed. When I look in Public folders on the 2003 box none are listed, when i look in PF Instances they are all listed. I know everything has moved to the 2010 server and I know 2010 is not showing the 2003 server as a replica for any folders. I am looking to use ADSI edit to remove the Public folder database from the 2003 server, but want to ensure i am going to delete the right thing so that they do not get deleted from the 2010 database. Should i delete configuration, Services, Microsoft Exchange, Company Name, Administrative groups, First administrative group, Servers, Server name, Information store, First storage group, public folder store (Server name)? Or something else? I have checked and the only public folder with the old exchange server listed as a replica is SYSTEM CONFIGURATION. Thanks in advance.

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  • Is it safe to compress my Windows 7 %USERPROFILE%\AppData folder?

    - by Kev
    Having just read Scott Hanselman's latest blog entry, Guide to Freeing up Disk Space under Windows 7, he suggests turning on NTFS compression which I already do for a number of less travelled folders that contain static files such as downloads or images. However I am wondering if it's wise to turn on NTFS compression for the whole of my %USERPROFILE%\AppData folder? My system drive is a 128 GB SSD residing in a Dell Precision T5400 3Ghz Quad Core Xeon workstation so I ought not to notice the extra cycles used to compress and decompress files on their way to and from the disk. However would there be any good reasons not to do this? In fact could I safely compress the whole of my %USERPROFILE% folder?

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  • Is it perfectly safe to install grub bootloader on regular partition?

    - by Flint
    One of the methods to do dual booting Windows with Linux OS is by installing grub boot loader onto Linux partition so you can retain Windows boot loader and let Windows handles the dual booting process. What's the odd that grub bootloader could partially overwrite the data at the beginning of the Linux partition and corrupt the file? Does grub actually check if there's a data at the beginning of the partition and move it to other location on the partition before writing its bootloader?

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  • Is domain-transfer inherently safe for downtime when the name servers remain the same?

    - by jlmt
    I've been reading around this topic towards understanding whether there's some or no chance of downtime during an upcoming domain transfer for 15 live and very critical domains. In our case there are three companies involved: CompanyA is the original registrar and DNS host, CompanyB is the new DNS host, and CompanyC is the new registrar. I've already changed the nameservers for all domains to those of CompanyB. We suffered some downtime because CompanyA deleted their hosted DNS for our domains directly after the change, but the changes propagated and we're now able to configure our DNS with CompanyB. From what I understand (please correct where wrong!): There exists an SOA record that points oneofourdomains.com to ns.companyb.com. That record is maintained and authoritatively hosted by the ccTLD registry for the domain (eg. Verisign for .com). CompanyA currently has the ability to change the SOA record because they're the registrar. There exist NS records for oneofourdomains.com, which are also related to the link from domain name to nameserver, are similarly hosted by the ccTLD, and which CompanyA are also able to change while acting as registrar. Neither CompanyB nor CompanyC currently have any control over the SOA or NS records. CompanyA are unable to cause us (DNS) problems during the transfer by dropping service early, because they are not the authoritative source for the SOA and NS records. When we transfer the domains, it's administrative control of the SOA and NS records that will be transferred to CompanyC. As long as we advise CompanyC that the SOA and NS records must not change (as regards pointing to CompanyB's nameservers), there's no need for any kind of DNS change, and therefore no possibility of downtime. Is my understanding of this correct? My fear is that CompanyA will somehow cut us off again, and their support dept hasn't given me much confidence in their understanding of the topic.

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  • Is it safe/wise to run Drupal alongside bespoke business web apps in production?

    - by Vaze
    I'm interested to know the general community feeling about the safety of running Drupal alongside bespoke, business critial ASP.NET MVC apps on a production server. Previously my employer's Drupal based 'visitor website' was hosted as a managed service with a 3rd party. While the LoB sites were hosted in-house. That 3rd party is no longer available so I'm considering my options: Bring Drupal in-house Find another 3rd party My concern is that I have little experience with Drupal administration (and no experience securing it) and that the addition of PHP to my IIS server poses a security risk. Is there a best practice that I can follow in this situation?

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  • Safe to use high port numbers? (re: obscuring web services)

    - by sofakng
    I have a small home network and I'm trying to balance the need for security versus convenience. The safest way to secure internal web servers is to only connect using VPNs but this seems overkill to protect a DVRs remote web interface (for example). As a compromise, would it be better to use very large ports numbers? (eg. five digits up to 65531) I've read that port scanners typically only scan the first 10,000 ports so using very high port numbers is a bit more secure. Is this true? Are there better ways to protect web servers? (ie. web guis for applications)

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  • Safe to use high port numbers? (re: obscuring web services)

    - by sofakng
    I have a small home network and I'm trying to balance the need for security versus convenience. The safest way to secure internal web servers is to only connect using VPNs but this seems overkill to protect a DVRs remote web interface (for example). As a compromise, would it be better to use very large ports numbers? (eg. five digits up to 65531) I've read that port scanners typically only scan the first 10,000 ports so using very high port numbers is a bit more secure. Is this true? Are there better ways to protect web servers? (ie. web guis for applications)

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  • Am I safe on Windows if I continue like this?

    - by max
    Of all the available tons of anti-malware software for Windows all over the internet, I've never used any paid solution(I am a student, I have no money). Since the last 10 years, my computers running Windows have never been hacked/compromised or infected so badly that I had to reformat them(of course I did reformat them for other reasons). The only program I have for security is Avast Home Edition, which is free, installed on my computers. It has never caused any problems; always detected malware, updated automatically, has an option to sandbox programs and everything else I need. Even if I got infected, I just did a boot-time scan with it, downloaded and ran Malwarebytes, scanned Autoruns logs, checked running processes with Process Explorer and did some other things and made sure I cleaned my computer. I am quite experienced and I've always taken basic precautions like not clicking suspicious executables, not going to sites which are suspicious according to WOT, and all that blah. But recently I've been doing more and more online transactions and since its 2012 now, I'm doubtful whether I need more security or not. Have I been just lucky, or do my computing habits obviate the need to use any more(or paid) security software?

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  • Is it safe to swap SATA ports during hibernation?

    - by netvope
    I hibernated my Windows 7 desktop PC, replaced the SATA cables of my 2 hard drives (without paying attention to which ports they were connected), and resumed the system. Everything appeared normal and it entered the desktop with all the applications previously open before hibernation. However, after a few seconds, the screen became frozen and the system no longer responded to anything (mouse/keyboard/network ping). Does anyone have a definitive answer on whether changing SATA ports of the HDDs during hibernation would crash a Windows 7 system?

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  • Is it safe to use up all memory on linux server, not leaving anything for the cache?

    - by Temnovit
    I have a CentOS server fully dedicated to MySQL 5.5 (with innodb tables mostly). Server has 32 GB RAM, SSD disks, and avarage memory usage looks like this: So about 25GB is in use and about 6.5GB is cached. I am experiencing performance problems with WRITE queries, so I was thinking, is this the optimal cache size? I might increase innodb buffer size, so that linux cache would become smaller, or decrease it, so it would be bigger. What is the optimal used/cached memory balance for busy MySQL server on linux?

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  • safe to setup NAS in virtual image with web server?

    - by Erik
    My current setup is Ubuntu Desktop, running Apache + MySQL + PHP stack. I use this image to host my small website to the outside world. I want to now run a virtual machine on the box, that will act as the FreeNAS box for my internal network. This sounds like a bad idea if the website gets hacked/attacked. Should I just give up and grab a dedicated machine instead? Can I instead virtualize the web server and NAS side by side on this machine?

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  • Using Plesk for webhosting on Ubuntu - Security risk or reasonably safe?

    - by user66952
    Sorry for this newb-question I'm pretty clueless about Plesk, only have limited debian (without Plesk) experience. If the question is too dumb just telling me how to ask a smarter one or what kind of info I should read first to improve the question would be appreciated as well. I want to offer a program for download on my website hosted on an Ubuntu 8.04.4 VPS using Plesk 9.3.0 for web-hosting. I have limited the ssh-access to the server via key only. When setting up the webhosting with Plesk it created an FTP-login & user is that a potential security risk that could bypass the key-only access? I think Plesk itself (even without the ftp-user-account) through it's web-interface could be a risk is that correct or are my concerns exaggerated? Would you say this solution makes a difference if I'm just using it for the next two weeks and then change servers to a system where I know more about security. 3.In other words is one less likely to get hacked within the first two weeks of having a new site up and running than in week 14&15? (due to occurring in less search results in the beginning perhaps, or for whatever reason... )

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  • Apache Tuscany 1.6 How do you set the JMS Binding Delivery Mode to NON_PERSISTENT?

    - by Robert Greiner
    I am using Tuscany 1.6 and am trying to set the Delivery Mode JMS Binding to NON_PERSISTENT. I've tried using uri="jms:MyService?deliveryMode=1" (which is what the spec (PDF) says to do) but, I ended up getting the following exception: Unknown token deliveryMode=1 I also tried <headers JMSDeliveryMode="NON_PERSISTENT"/>, although I did not get an exception the messages still got delivered as PERSISTENT. This is the format for the URI jms:<jms-dest>? connectionFactoryName=<Connection-Factory-Name> & destinationType={queue|topic} deliveryMode=<Delivery-Mode> & timeToLive=<Time-To-Live> & priority=<Priority> & <User-Property>=<User-Property-Value> & … This is the example I am using <composite xmlns="http://www.osoa.org/xmlns/sca/1.0" name="MyValueComposite"> <service name="MyValueService"> <interface.java interface="services.myvalue.MyValueService"/> <binding.jms uri="jms:MyValueServiceQueue?activationSpecName=MyValueServiceAS&... "/> </service> <reference name="StockQuoteService"> <interface.java interface="services.stockquote.StockQuoteService"/> <binding.jms uri="jms:StockQuoteServiceQueue?connectionFactoryName=StockQuoteServiceQCF&deliveryMode=1&... "/> </reference> </composite>

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  • How do I run a VBScript in 32-bit mode on a 64-bit machine?

    - by Peter
    I have a text file that ends with .vbs that I have written the following in: Set Conn = CreateObject("ADODB.Connection") Conn.Provider = "Microsoft.ACE.OLEDB.12.0" Conn.Properties("Data Source") = "C:\dummy.accdb" Conn.Properties("Jet OLEDB:Database Password") = "pass" Conn.Open Conn.Close Set Conn = Nothing When I execute this on a Windows 32-bit machine it runs and ends without any notion (expected). When I execute this on a Windows 64-bit machine it gets the error "Provider cannot be found. It may not be properly installed.". But it is installed. I think the root of the problem is that the provider is a 32-bit provider, as far as I know it doesn't exist as 64-bit. If I run the VBScript through IIS on my 64-bit machine (as a ASP file) I can select that it should run in 32-bit mode. It can then find the provider. How can I make it find the provider on Windows 64-bit? Can I tell CScript (which executes the .vbs text file) to run in 32-bit mode somehow?

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  • How can I show print statements in debug mode of OPNET Modeler?

    - by Here now
    I'm writing C++ code in OPNET Modeler. I try to simulate my scenario in debugger mode & I need to trace the function that I wrote it. I need to show print statements which I put it in my code. I used in debugger mode: ***ltr function_name()*** then ***c*** But the result looks like: Type 'help' for Command Summary ODB> ltr enqueue_packet() Added trace #0: trace on label (enqueue_packet()) ODB> c |-----------------------------------------------------------------------------| | Progress: Time (1 min. 52 sec.); Events (500,002) | | Speed: Average (82,575 events/sec.); Current (82,575 events/sec.) | | Time : Elapsed (6.1 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Progress: Time (1 min. 55 sec.); Events (1,000,002) | | Speed: Average (69,027 events/sec.); Current (59,298 events/sec.) | | Time : Elapsed (14 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Progress: Time (1 min. 59 sec.); Events (1,500,002) | | Speed: Average (51,464 events/sec.); Current (34,108 events/sec.) | | Time : Elapsed (29 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Simulation Completed - Collating Results. | | Events: Total (1,591,301); Average Speed (48,803 events/sec.) | | Time : Elapsed (33 sec.); Simulated (2 min. 0 sec.) | | DES Log: 29 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Reading network model. | |-----------------------------------------------------------------------------| I need to show the print statements in my code. Where it has to be appeared? Is there any step before run the simulation to insure that OPNET debugger using Visual Studio & go through my code??

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  • What is the safe way to use fork with Apache::DBI under mod_perl2?

    - by codeholic
    I have a problem when I use Apache::DBI in child processes. The problem is that Apache::DBI provides a single handle for all processes which use it, so I get DBD::mysql::db selectall_arrayref failed: Commands out of sync; you can't run this command now at /usr/local/www/apache22/data/test-fork.cgi line 20. Reconnection doesn't help, since Apache::DBI reconnects in all processes, as I understood the following error The server encountered an internal error and was unable to complete your request. Error message: DBD driver has not implemented the AutoCommit attribute at /usr/local/lib/perl5/site_perl/5.8.9/Apache/DBI.pm line 283. , Here's the origin code: use Data::Dumper 'Dumper'; use DBI (); my $dbh = DBI->connect($dsn, $username, $password, { RaiseError => 1, PrintError => 0, }); my $file = "/tmp/test-fork.tmp"; my $pid = fork; defined $pid or die "fork: $!"; if ($pid) { my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') }; print "Content-Type: text/plain\n\n"; print $rows ? "parent: " . Dumper($rows) : $@; } else { my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') }; open FH, '>', $file or die "$file: $!"; print FH $rows ? "child: " . Dumper($rows) : $@; close FH; } The code I used for reconnection: ... else { $dbh->disconnect; $dbh = DBI->connect($dsn, $username, $password, $attrs); my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') }; open FH, '>', $file or die "$file: $!"; print FH $rows ? "child: " . Dumper($rows) : $@; close FH; } Is there a safe way to use Apache::DBI with forking? Is there a way to make it create a new connection perhaps?

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  • How do I create a thread-safe write-once read-many value in Java?

    - by Software Monkey
    This is a problem I encounter frequently in working with more complex systems and which I have never figured out a good way to solve. It usually involves variations on the theme of a shared object whose construction and initialization are necessarily two distinct steps. This is generally because of architectural requirements, similar to applets, so answers that suggest I consolidate construction and initialization are not useful. By way of example, let's say I have a class that is structured to fit into an application framework like so: public class MyClass { private /*ideally-final*/ SomeObject someObject; MyClass() { someObject=null; } public void startup() { someObject=new SomeObject(...arguments from environment which are not available until startup is called...); } public void shutdown() { someObject=null; // this is not necessary, I am just expressing the intended scope of someObject explicitly } } I can't make someObject final since it can't be set until startup() is invoked. But I would really like it to reflect it's write-once semantics and be able to directly access it from multiple threads, preferably avoiding synchronization. The idea being to express and enforce a degree of finalness, I conjecture that I could create a generic container, like so: public class WoRmObject<T> { private T object; WoRmObject() { object=null; } public WoRmObject set(T val) { object=val; return this; } public T get() { return object; } } and then in MyClass, above, do: private final WoRmObject<SomeObject> someObject; MyClass() { someObject=new WoRmObject<SomeObject>(); } public void startup() { someObject.set(SomeObject(...arguments from environment which are not available until startup is called...)); } Which raises some questions for me: Is there a better way, or existing Java object (would have to be available in Java 4)? Is this thread-safe provided that no other thread accesses someObject.get() until after it's set() has been called. The other threads will only invoke methods on MyClass between startup() and shutdown() - the framework guarantees this. Given the completely unsynchronized WoRmObject container, it is ever possible under either JMM to see a value of object which is neither null nor a reference to a SomeObject? In other words, does has the JMM always guaranteed that no thread can observe the memory of an object to be whatever values happened to be on the heap when the object was allocated.

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  • Is it possible to make this Flex/Flash application safe?

    - by Frank
    I'm back with another Flex/Flash security question. I've already received some help from the community on this topic, but I'm still not quite sure this is the best way to do. Here's the thing. A flex web app, a lot of users (1000+), custom configuration of the application depending of the user group. Can I make this thing safe... or safer. For the moment, when a user comes to the application, there is only one configuration possible, but for the next version we've implented a multi-configuration protocol, this way : 1. The user connect to Default.aspx, server code process the windows credentials (whe are on intranet) and give the correct xml configuration file. 2. The flex app loads with the xml conf file as a flashvar and then the app 'builds' itself with the content of the xml file. As we know, since this is a flex application the swf is downloaded on the client computer and the xml file too. If more than one user connects to the app, from the same computer, the can possibly see the other xml file in the windows temp folder. The current directory of the application looks that way : Web site |-> default.aspx |-> index.swf |-> configAdmin.xml |-> configUserType1.xml |-> configUserType2.xml |-> com |-> a lot of swf and xml files I was first thinking making another directory (without read access for the client) containing all the configurations xml files, picking the right one, copying it to the client and deleting it afterwards. But it seems like I must let know the user know when downloading/deleting content on it's computer... I'm running out of ideas, so I hope you have some great ones. It's there are some design flaws (in the way the app is build, not in Flash :p) please share. I'm always looking forward to improve. Thanks Update : In browser Flash/Flex (without AIR that is) doesn't allow deleting file localy silently (on the client computer, where the application is). It's also not yet possible to get session data.

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  • Is it thread safe to read a form controls value (but not change it) without using Invoke/BeginInvoke from another thread

    - by goku_da_master
    I know you can read a gui control from a worker thread without using Invoke/BeginInvoke because my app is doing it now. The cross thread exception error is not being thrown and my System.Timers.Timer thread is able to read gui control values just fine (unlike this guy: can a worker thread read a control in the GUI?) Question 1: Given the cardinal rule of threads, should I be using Invoke/BeginInvoke to read form control values? And does this make it more thread-safe? The background to this question stems from a problem my app is having. It seems to randomly corrupt form controls another thread is referencing. (see question 2) Question 2: I have a second thread that needs to update form control values so I Invoke/BeginInvoke to update those values. Well this same thread needs a reference to those controls so it can update them. It holds a list of these controls (say DataGridViewRow objects). Sometimes (not always), the DataGridViewRow reference gets "corrupt". What I mean by corrupt, is the reference is still valid, but some of the DataGridViewRow properties are null (ex: row.Cells). Is this caused by question 1 or can you give me any tips on why this might be happening? Here's some code (the last line has the problem): public partial class MyForm : Form { void Timer_Elapsed(object sender) { // we're on a new thread (this function gets called every few seconds) UpdateUiHelper updateUiHelper = new UpdateUiHelper(this); foreach (DataGridViewRow row in dataGridView1.Rows) { object[] values = GetValuesFromDb(); updateUiHelper.UpdateRowValues(row, values[0]); } // .. do other work here updateUiHelper.UpdateUi(); } } public class UpdateUiHelper { private readonly Form _form; private Dictionary<DataGridViewRow, object> _rows; private delegate void RowDelegate(DataGridViewRow row); private readonly object _lockObject = new object(); public UpdateUiHelper(Form form) { _form = form; _rows = new Dictionary<DataGridViewRow, object>(); } public void UpdateRowValues(DataGridViewRow row, object value) { if (_rows.ContainsKey(row)) _rows[row] = value; else { lock (_lockObject) { _rows.Add(row, value); } } } public void UpdateUi() { foreach (DataGridViewRow row in _rows.Keys) { SetRowValueThreadSafe(row); } } private void SetRowValueThreadSafe(DataGridViewRow row) { if (_form.InvokeRequired) { _form.Invoke(new RowDelegate(SetRowValueThreadSafe), new object[] { row }); return; } // now we're on the UI thread object newValue = _rows[row]; row.Cells[0].Value = newValue; // randomly errors here with NullReferenceException, but row is never null! }

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  • python- scipy optimization

    - by pear
    In scipy fmin_slsqp (Sequential Least Squares Quadratic Programming), I tried reading the code 'slsqp.py' provided with the scipy package, to find what are the criteria to get the exit_modes 0? I cannot find which statements in the code produce this exit mode? Please help me 'slsqp.py' code as follows, exit_modes = { -1 : "Gradient evaluation required (g & a)", 0 : "Optimization terminated successfully.", 1 : "Function evaluation required (f & c)", 2 : "More equality constraints than independent variables", 3 : "More than 3*n iterations in LSQ subproblem", 4 : "Inequality constraints incompatible", 5 : "Singular matrix E in LSQ subproblem", 6 : "Singular matrix C in LSQ subproblem", 7 : "Rank-deficient equality constraint subproblem HFTI", 8 : "Positive directional derivative for linesearch", 9 : "Iteration limit exceeded" } def fmin_slsqp( func, x0 , eqcons=[], f_eqcons=None, ieqcons=[], f_ieqcons=None, bounds = [], fprime = None, fprime_eqcons=None, fprime_ieqcons=None, args = (), iter = 100, acc = 1.0E-6, iprint = 1, full_output = 0, epsilon = _epsilon ): # Now do a lot of function wrapping # Wrap func feval, func = wrap_function(func, args) # Wrap fprime, if provided, or approx_fprime if not if fprime: geval, fprime = wrap_function(fprime,args) else: geval, fprime = wrap_function(approx_fprime,(func,epsilon)) if f_eqcons: # Equality constraints provided via f_eqcons ceval, f_eqcons = wrap_function(f_eqcons,args) if fprime_eqcons: # Wrap fprime_eqcons geval, fprime_eqcons = wrap_function(fprime_eqcons,args) else: # Wrap approx_jacobian geval, fprime_eqcons = wrap_function(approx_jacobian, (f_eqcons,epsilon)) else: # Equality constraints provided via eqcons[] eqcons_prime = [] for i in range(len(eqcons)): eqcons_prime.append(None) if eqcons[i]: # Wrap eqcons and eqcons_prime ceval, eqcons[i] = wrap_function(eqcons[i],args) geval, eqcons_prime[i] = wrap_function(approx_fprime, (eqcons[i],epsilon)) if f_ieqcons: # Inequality constraints provided via f_ieqcons ceval, f_ieqcons = wrap_function(f_ieqcons,args) if fprime_ieqcons: # Wrap fprime_ieqcons geval, fprime_ieqcons = wrap_function(fprime_ieqcons,args) else: # Wrap approx_jacobian geval, fprime_ieqcons = wrap_function(approx_jacobian, (f_ieqcons,epsilon)) else: # Inequality constraints provided via ieqcons[] ieqcons_prime = [] for i in range(len(ieqcons)): ieqcons_prime.append(None) if ieqcons[i]: # Wrap ieqcons and ieqcons_prime ceval, ieqcons[i] = wrap_function(ieqcons[i],args) geval, ieqcons_prime[i] = wrap_function(approx_fprime, (ieqcons[i],epsilon)) # Transform x0 into an array. x = asfarray(x0).flatten() # Set the parameters that SLSQP will need # meq = The number of equality constraints if f_eqcons: meq = len(f_eqcons(x)) else: meq = len(eqcons) if f_ieqcons: mieq = len(f_ieqcons(x)) else: mieq = len(ieqcons) # m = The total number of constraints m = meq + mieq # la = The number of constraints, or 1 if there are no constraints la = array([1,m]).max() # n = The number of independent variables n = len(x) # Define the workspaces for SLSQP n1 = n+1 mineq = m - meq + n1 + n1 len_w = (3*n1+m)*(n1+1)+(n1-meq+1)*(mineq+2) + 2*mineq+(n1+mineq)*(n1-meq) \ + 2*meq + n1 +(n+1)*n/2 + 2*m + 3*n + 3*n1 + 1 len_jw = mineq w = zeros(len_w) jw = zeros(len_jw) # Decompose bounds into xl and xu if len(bounds) == 0: bounds = [(-1.0E12, 1.0E12) for i in range(n)] elif len(bounds) != n: raise IndexError, \ 'SLSQP Error: If bounds is specified, len(bounds) == len(x0)' else: for i in range(len(bounds)): if bounds[i][0] > bounds[i][1]: raise ValueError, \ 'SLSQP Error: lb > ub in bounds[' + str(i) +'] ' + str(bounds[4]) xl = array( [ b[0] for b in bounds ] ) xu = array( [ b[1] for b in bounds ] ) # Initialize the iteration counter and the mode value mode = array(0,int) acc = array(acc,float) majiter = array(iter,int) majiter_prev = 0 # Print the header if iprint >= 2 if iprint >= 2: print "%5s %5s %16s %16s" % ("NIT","FC","OBJFUN","GNORM") while 1: if mode == 0 or mode == 1: # objective and constraint evaluation requird # Compute objective function fx = func(x) # Compute the constraints if f_eqcons: c_eq = f_eqcons(x) else: c_eq = array([ eqcons[i](x) for i in range(meq) ]) if f_ieqcons: c_ieq = f_ieqcons(x) else: c_ieq = array([ ieqcons[i](x) for i in range(len(ieqcons)) ]) # Now combine c_eq and c_ieq into a single matrix if m == 0: # no constraints c = zeros([la]) else: # constraints exist if meq > 0 and mieq == 0: # only equality constraints c = c_eq if meq == 0 and mieq > 0: # only inequality constraints c = c_ieq if meq > 0 and mieq > 0: # both equality and inequality constraints exist c = append(c_eq, c_ieq) if mode == 0 or mode == -1: # gradient evaluation required # Compute the derivatives of the objective function # For some reason SLSQP wants g dimensioned to n+1 g = append(fprime(x),0.0) # Compute the normals of the constraints if fprime_eqcons: a_eq = fprime_eqcons(x) else: a_eq = zeros([meq,n]) for i in range(meq): a_eq[i] = eqcons_prime[i](x) if fprime_ieqcons: a_ieq = fprime_ieqcons(x) else: a_ieq = zeros([mieq,n]) for i in range(mieq): a_ieq[i] = ieqcons_prime[i](x) # Now combine a_eq and a_ieq into a single a matrix if m == 0: # no constraints a = zeros([la,n]) elif meq > 0 and mieq == 0: # only equality constraints a = a_eq elif meq == 0 and mieq > 0: # only inequality constraints a = a_ieq elif meq > 0 and mieq > 0: # both equality and inequality constraints exist a = vstack((a_eq,a_ieq)) a = concatenate((a,zeros([la,1])),1) # Call SLSQP slsqp(m, meq, x, xl, xu, fx, c, g, a, acc, majiter, mode, w, jw) # Print the status of the current iterate if iprint > 2 and the # major iteration has incremented if iprint >= 2 and majiter > majiter_prev: print "%5i %5i % 16.6E % 16.6E" % (majiter,feval[0], fx,linalg.norm(g)) # If exit mode is not -1 or 1, slsqp has completed if abs(mode) != 1: break majiter_prev = int(majiter) # Optimization loop complete. Print status if requested if iprint >= 1: print exit_modes[int(mode)] + " (Exit mode " + str(mode) + ')' print " Current function value:", fx print " Iterations:", majiter print " Function evaluations:", feval[0] print " Gradient evaluations:", geval[0] if not full_output: return x else: return [list(x), float(fx), int(majiter), int(mode), exit_modes[int(mode)] ]

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  • How to design authentication in a thick client, to be fail safe?

    - by Jay
    Here's a use case: I have a desktop application (built using Eclipse RCP) which on start, pops open a dialog box with 'UserName' and 'Password' fields in it. Once the end user, inputs his UserName and Password, a server is contacted (a spring remote-servlet, with the client side being a spring httpclient: similar to the approaches here.), and authentication is performed on the server side. A few questions related to the above mentioned scenario: If said this authentication service were to go down, what would be the best way to handle further proceedings? Authentication is something that I cannot do away with. Would running the desktop client in a "limited" mode be a good idea? For instance, important features/menus/views will be disabled, rest of the application will be accessible? Should I have a back up authentication service running on a different machine, working as a backup? What are the general best-practices in this scenario? I remember reading about google gears and how it would let you edit and do stuff offline - should something like this be designed? Please let me know your design/architectural comments/suggestions. Appreciate your help.

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  • Safe, standard way to load images in ListView on a different thread?

    - by Po
    Before making this question, I have searched and read these ones: http://stackoverflow.com/questions/541966/android-how-do-i-do-a-lazy-load-of-images-in-listview http://stackoverflow.com/questions/1409623/android-issue-with-lazy-loading-images-into-a-listview My problem is I have a ListView, where: Each row contains an ImageView, whose content is to be loaded from the internet Each row's view is recycled as in ApiDemo's List14 What I want ultimately: Load images lazily, only when the user scrolls to them Load images on different thread(s) to maintain responsiveness My current approach: In the adapter's getView() method, apart from setting up other child views, I launch a new thread that loads the Bitmap from the internet. When that loading thread finishes, it returns the Bitmap to be set on the ImageView (I do this using AsyncTask or Handler). Because I recycle ImageViews, it may be the case that I first want to set a view with Bitmap#1, then later want to set it to Bitmap#2 when the user scrolls down. Bitmap#1 may happen to take longer than Bitmap#2 to load, so it may end up overwriting Bitmap#2 on the view. I solve this by maintaining a WeakHashMap that remembers the last Bitmap I want to set for that view. Below is somewhat a pseudocode for my current approach. I've ommitted other details like caching, just to keep the thing clear. public class ImageLoader { // keeps track of the last Bitmap we want to set for this ImageView private static final WeakHashMap<ImageView, AsyncTask> assignments = new WeakHashMap<ImageView, AsyncTask>(); /** Asynchronously sets an ImageView to some Bitmap loaded from the internet */ public static void setImageAsync(final ImageView imageView, final String imageUrl) { // cancel whatever previous task AsyncTask oldTask = assignments.get(imageView); if (oldTask != null) { oldTask.cancel(true); } // prepare to launch a new task to load this new image AsyncTask<String, Integer, Bitmap> newTask = new AsyncTask<String, Integer, Bitmap>() { protected void onPreExecute() { // set ImageView to some "loading..." image } protected Bitmap doInBackground(String... urls) { return loadFromInternet(imageUrl); } protected void onPostExecute(Bitmap bitmap) { // set Bitmap if successfully loaded, or an "error" image if (bitmap != null) { imageView.setImageBitmap(bitmap); } else { imageView.setImageResource(R.drawable.error); } } }; newTask.execute(); // mark this as the latest Bitmap we want to set for this ImageView assignments.put(imageView, newTask); } /** returns (Bitmap on success | null on error) */ private Bitmap loadFromInternet(String imageUrl) {} } Problem I still have: what if the Activity gets destroyed while some images are still loading? Is there any risk when the loading thread calls back to the ImageView later, when the Activity is already destroyed? Moreover, AsyncTask has some global thread-pool underneath, so if lengthy tasks are not canceled when they're not needed anymore, I may end up wasting time loading things users don't see. My current design of keeping this thing globally is too ugly, and may eventually cause some leaks that are beyond my understanding. Instead of making ImageLoader a singleton like this, I'm thinking of actually creating separate ImageLoader objects for different Activities, then when an Activity gets destroyed, all its AsyncTask will be canceled. Is this too awkward? Anyway, I wonder if there is a safe and standard way of doing this in Android. In addition, I don't know iPhone but is there a similar problem there and do they have a standard way to do this kind of task? Many thanks.

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