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  • What scientific plotting software is available?

    - by Helix
    I am currently doing some experimental work and I have a lot of data to trawl though. I use Gnumeric, and it's very good, but often I feel there has to be something better. Ideally I would like the maximum number of features with a minimal learning curve, but really I'd just like to know if there is something better than Gnumeric that I can use for manipulating and plotting data. What would you recommend?

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  • compact Number formatting behavior in Java (automatically switch between decimal and scientific notation)

    - by kostmo
    I am looking for a way to format a floating point number dynamically in either standard decimal format or scientific notation, depending on the value of the number. For moderate magnitudes, the number should be formatted as a decimal with trailing zeros suppressed. If the floating point number is equal to an integral value, the decimal point should also be suppressed. For extreme magnitudes (very small or very large), the number should be expressed in scientific notation. Alternately stated, if the number of characters in the expression as standard decimal notation exceeds a certain threshold, switch to scientific notation. I should have control over the maximum number of digits of precision, but I don't want trailing zeros appended to express the minimum precision; all trailing zeros should be suppressed. Basically, it should optimize for compactness and readability. 2.80000 - 2.8 765.000000 - 765 0.0073943162953 - 0.00739432 (limit digits of precision—to 6 in this case) 0.0000073943162953 - 7.39432E-6 (switch to scientific notation if the magnitude is small enough—less than 1E-5 in this case) 7394316295300000 - 7.39432E+6 (switch to scientific notation if the magnitude is large enough—for example, when greater than 1E+10) 0.0000073900000000 - 7.39E-6 (strip trailing zeros from significand in scientific notation) 0.000007299998344 - 7.3E-6 (rounding from the 6-digit precision limit causes this number to have trailing zeros which are stripped) Here's what I've found so far: The .toString() method of the Number class does most of what I want, except it doesn't upconvert to integer representation when possible, and it will not express large integral magnitudes in scientific notation. Also, I'm not sure how to adjust the precision. The "%G" format string to the String.format(...) function allows me to express numbers in scientific notation with adjustable precision, but does not strip trailing zeros. I'm wondering if there's already some library function out there that meets these criteria. I guess the only stumbling block for writing this myself is having to strip the trailing zeros from the significand in scientific notation produced by %G.

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  • Configuration management in support of scientific computing

    - by Sharpie
    For the past few years I have been involved with developing and maintaining a system for forecasting near-shore waves. Our team has just received a significant grant for further development and as a result we are taking the opportunity to refactor many components of the old system. We will also be receiving a new server to run the model and so I am taking this opportunity to consider how we set up the system. Basically, the steps that need to happen are: Some standard packages and libraries such as compilers and databases need to be downloaded and installed. Some custom scientific models need to be downloaded and compiled from source as they are not commonly provided as packages. New users need to be created to manage the databases and run the models. A suite of scripts that manage model-database interaction needs to be checked out from source code control and installed. Crontabs need to be set up to run the scripts at regular intervals in order to generate forecasts. I have been pondering applying tools such as Puppet, Capistrano or Fabric to automate the above steps. It seems perfectly possible to implement most of the above functionality except there are a couple usage cases that I am wondering about: During my preliminary research, I have found few examples and little discussion on how to use these systems to abstract and automate the process of building custom components from source. We may have to deploy on machines that are isolated from the Internet- i.e. all configuration and set up files will have to come in on a USB key that can be inserted into a terminal that can connect to the server that will run the models. I see this as an opportunity to learn a new tool that will help me automate my workflow, but I am unsure which tool I should start with. If any member of the community could suggest a tool that would support the above workflow and the issues specific to scientific computing, I would be very grateful. Our production server will be running Linux, but support for OS X would be a bonus as it would allow the development team to setup test installations outside of VirtualBox.

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  • Configuration management in support of scientific computing

    - by Sharpie
    For the past few years I have been involved with developing and maintaining a system for forecasting near-shore waves. Our team has just received a significant grant for further development and as a result we are taking the opportunity to refactor many components of the old system. We will also be receiving a new server to run the model and so I am taking this opportunity to consider how we set up the system. Basically, the steps that need to happen are: Some standard packages and libraries such as compilers and databases need to be downloaded and installed. Some custom scientific models need to be downloaded and compiled from source as they are not commonly provided as packages. New users need to be created to manage the databases and run the models. A suite of scripts that manage model-database interaction needs to be checked out from source code control and installed. Crontabs need to be set up to run the scripts at regular intervals in order to generate forecasts. I have been pondering applying tools such as Puppet, Capistrano or Fabric to automate the above steps. It seems perfectly possible to implement most of the above functionality except there are a couple usage cases that I am wondering about: During my preliminary research, I have found few examples and little discussion on how to use these systems to abstract and automate the process of building custom components from source. We may have to deploy on machines that are isolated from the Internet- i.e. all configuration and set up files will have to come in on a USB key that can be inserted into a terminal that can connect to the server that will run the models. I see this as an opportunity to learn a new tool that will help me automate my workflow, but I am unsure which tool I should start with. If any member of the community could suggest a tool that would support the above workflow and the issues specific to scientific computing, I would be very grateful. Our production server will be running Linux, but support for OS X would be a bonus as it would allow the development team to setup test installations outside of VirtualBox.

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  • Changing file browser in Scientific Linux

    - by karolg
    I use Scientific Linux Release 6.1 (Carbon) with GNOME 2.28.2. When I double-click on a folder on the Desktop it is opened in "File Browser". When I open a folder via "Places" on the Main Menu Bar, the folder is opened in "File Manager". I dislike "File Manager" and I don't understand why there are two different programs (file managers) running depending on how I open a folder. How can I get rid of "File Manager"?

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  • Scientific Linux - mysql and apachefail to start on reboot

    - by Derek Deed
    Both mysqld and httpd fail to restart following a reboot of the server, although chkconfig --list shows both daemons set to on for run levels 2,3,4 & 5 All control is being exectuted via Webmin Reboot server – MySQl and Apache not running MySQL Database Server MySQL version 5.1.69 MySQL is not running on your system - database list could not be retrieved. Click this button to start the MySQL database server on your system with the command /etc/rc.d/init.d/mysqld start. This Webmin module cannot administer the database until it is started. Apache Webserver Apache version 2.2.15 Start Apache Search Docs.. Global configuration Existing virtual hosts Create virtual host Select all. | Invert selection. Default Server Defines the default settings for all other virtual servers, and processes any unhandled requests. Address Any Port Any Server Name Automatic Document Root /var/www/drupal Virtual Server Processes all requests on port 443 not handled by other virtual servers. Address Any Port 443 Server Name Automatic Document Root /var/www/drupal Select all. | Invert selection. chkconfig --list mysqld mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off chkconfig --list httpd httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off Manually Restart Apache chkconfig --list httpd httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off Manually Restart MySQL chkconfig --list mysqld mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off Everything now running okay; but no difference in the chkconfig outputs above. Set chkconfig --levels 235 httpd on /etc/init.d/httpd start The same for mysqld but no change in operation. Log files show that the shutdown has been completed successfully; but there is no indication of the service restarting until it is executed manually: 131112 13:59:15 InnoDB: Starting shutdown... 131112 13:59:16 InnoDB: Shutdown completed; log sequence number 0 881747021 131112 13:59:16 [Note] /usr/libexec/mysqld: Shutdown complete 131112 13:59:16 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended 131112 14:09:52 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 131112 14:09:52 InnoDB: Initializing buffer pool, size = 8.0M 131112 14:09:52 InnoDB: Completed initialization of buffer pool [Tue Nov 12 13:59:13 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Tue Nov 12 13:59:13 2013] [notice] Digest: generating secret for digest authentication ... [Tue Nov 12 13:59:13 2013] [notice] Digest: done [Tue Nov 12 13:59:14 2013] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips configured -- resuming normal operations [Tue Nov 12 13:59:14 2013] [notice] caught SIGTERM, shutting down [Tue Nov 12 14:27:13 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Tue Nov 12 14:27:13 2013] [notice] Digest: generating secret for digest authentication ... [Tue Nov 12 14:27:13 2013] [notice] Digest: done [Tue Nov 12 14:27:13 2013] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips configured -- resuming normal operations Is anyone able to shed any light on this problem, Cheers, Derek.

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  • Scientific Linux - mysql and apache fail to start on reboot

    - by Derek Deed
    Both mysqld and httpd fail to restart following a reboot of the server, although chkconfig --list shows both daemons set to on for run levels 2,3,4 & 5 All control is being exectuted via Webmin Reboot server – MySQl and Apache not running MySQL Database Server MySQL version 5.1.69 MySQL is not running on your system - database list could not be retrieved. ________________________________________ Click this button to start the MySQL database server on your system with the command /etc/rc.d/init.d/mysqld start. This Webmin module cannot administer the database until it is started. Apache Webserver Apache version 2.2.15 Start Apache Search Docs.. Global configuration Existing virtual hosts Create virtual host Select all. | Invert selection. Default Server Defines the default settings for all other virtual servers, and processes any unhandled requests. Address Any Port Any Server Name Automatic Document Root /var/www/drupal Virtual Server Processes all requests on port 443 not handled by other virtual servers. Address Any Port 443 Server Name Automatic Document Root /var/www/drupal Select all. | Invert selection. chkconfig --list mysqld mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off chkconfig --list httpd httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off Manually Restart Apache chkconfig --list httpd httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off Manually Restart MySQL chkconfig --list mysqld mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off Everything now running okay; but no difference in the chkconfig outputs above. I tried: chkconfig --levels 235 httpd on /etc/init.d/httpd start and the same for mysqld but no change in operation. Log files show that the shutdown has been completed successfully; but there is no indication of the service restarting until it is executed manually: 131112 13:59:15 InnoDB: Starting shutdown... 131112 13:59:16 InnoDB: Shutdown completed; log sequence number 0 881747021 131112 13:59:16 [Note] /usr/libexec/mysqld: Shutdown complete 131112 13:59:16 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended 131112 14:09:52 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 131112 14:09:52 InnoDB: Initializing buffer pool, size = 8.0M 131112 14:09:52 InnoDB: Completed initialization of buffer pool And the Apache logs: [Tue Nov 12 13:59:13 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Tue Nov 12 13:59:13 2013] [notice] Digest: generating secret for digest authentication ... [Tue Nov 12 13:59:13 2013] [notice] Digest: done [Tue Nov 12 13:59:14 2013] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips configured -- resuming normal operations [Tue Nov 12 13:59:14 2013] [notice] caught SIGTERM, shutting down [Tue Nov 12 14:27:13 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Tue Nov 12 14:27:13 2013] [notice] Digest: generating secret for digest authentication ... [Tue Nov 12 14:27:13 2013] [notice] Digest: done [Tue Nov 12 14:27:13 2013] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 mod_ssl/2.2.15 OpenSSL/1.0.0-fips configured -- resuming normal operations Is anyone able to shed any light on this problem?

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  • F# performance in scientific computing

    - by aaa
    hello. I am curious as to how F# performance compares to C++ performance? I asked a similar question with regards to Java, and the impression I got was that Java is not suitable for heavy numbercrunching. I have read that F# is supposed to be more scalable and more performant, but how is this real-world performance compares to C++? specific questions about current implementation are: How well does it do floating-point? Does it allow vector instructions how friendly is it towards optimizing compilers? How big a memory foot print does it have? Does it allow fine-grained control over memory locality? does it have capacity for distributed memory processors, for example Cray? what features does it have that may be of interest to computational science where heavy number processing is involved? Are there actual scientific computing implementations that use it? Thanks

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  • Managed language for scientific computing software

    - by heisen
    Scientific computing is algorithm intensive and can also be data intensive. It often needs to use a lot of memory to run analysis and release it before continuing with the next. Sometime it also uses memory pool to recycle memory for each analysis. Managed language is interesting here because it can allow the developer to concentrate on the application logic. Since it might need to deal with huge dataset, performance is important too. But how can we control memory and performance with managed language?

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  • Reading ASCII numbers using "D" instead of "E" for scientific notation using C

    - by Arrieta
    Hello, I have a list of numbers which looks like this: 1.234D+1 or 1.234D-02. I want to read the file using C. The function atof will merely ignore the D and translate only the mantissa. The function fscanf will not accept the format '%10.6e' because it expects an E instead of a D in the exponent. When I ran into this problem in Python, I have up and merely used a string substitution before converting from string to float. But in C, I am sure there must be another way. So, how would you read a file with numbers using D instead of E for scientific notation? Notice that I do not mean how to read the strings themselves, but rather how to convert them to floats. Thanks.

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  • Greek/latin scientific JLabel in Java Swing application

    - by MartinStettner
    For a scientific application I want to design an input form which lets the user enter certain parameters. Some of them are designated using greek letters, some of them have latin letters. The parameter names should be displayed using ordinary JLabel controls. On Windows, the Tahoma font (which is used for Labels by default) contains both latin and greek letters, so I simply set the Text property of the label to a greek (unicode) string and everything works fine. I'm wondering if this works also without modifications on Linux and OSX systems resp. for which Java/OS versions this would work. Also I'm curious if there's an easy way to show subscripts in labels ("\eta_0" in TeX), but this is not that important for my application ...

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  • Industry-style practices for increasing productivity in a small scientific environment

    - by drachenfels
    Hi, I work in a small, independent scientific lab in a university in the United States, and it has come to my notice that, compared with a lot of practices that are ostensibly followed in the industry, like daily checkout into a version control system, use of a single IDE/editor for all languages (like emacs), etc, we follow rather shoddy programming practices. So, I was thinking of getting together all my programs, scripts, etc, and building a streamlined environment to increase productivity. I'd like suggestions from people on Stack Overflow for the same. Here is my primary plan.: I use MATLAB, C and Python scripts, and I'd like to edit, compile them from a single editor, and ensure correct version control. (questions/things for which I'd like suggestions are in italics) 1] Install Cygwin, and get it to work well with Windows so I can use git or a similar version control system (is there a DVCS which can work directly from the windows CLI, so I can skip the Cygwin step?). 2] Set up emacs to work with C, Python, and MATLAB files, so I can edit and compile all three at once from a single editor (say, emacs) (I'm not very familiar with the emacs menu, but is there a way to set the path to the compiler for certain languages? I know I can Google this, but emacs documentation has proved very hard for me to read so far, so I'd appreciate it if someone told me in simple language) 3] Start checking in code at the end of each day or half-day so as to maintain a proper path of progress of my code (two questions), can you checkout files directly from emacs? is there a way to checkout LabVIEW files into a DVCS like git? Lastly, I'd like to apologize for the rather vague nature of the question, and hope I shall learn to ask better questions over time. I'd appreciate it if people gave their suggestions, though, and point to any resources which may help me learn.

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  • Convert scientific notation to decimal notation

    - by Ankur
    There is a similar question on SO which suggests using NumberFormat which is what I have done. I am using the parse() method of NumberFormat. public static void main(String[] args) throws ParseException{ DecToTime dtt = new DecToTime(); dtt.decToTime("1.930000000000E+02"); } public void decToTime(String angle) throws ParseException{ DecimalFormat dform = new DecimalFormat(); //ParsePosition pp = new ParsePosition(13); Number angleAsNumber = dform.parse(angle); System.out.println(angleAsNumber); } The result I get is 1.93 I didn't really expect this to work because 1.930000000000E+02 is a pretty unusual looking number, do I have to do some string parsing first to remove the zeros? Or is there a quick and elegant way?

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  • Scientific Plotting in Python

    - by user100046
    I have a large data set of tuples containing (time of event, latitude, longitude) that I need to visualize. I was hoping to generate a 'movie'-like xy-plot, but was wondering if anyone has a better idea or if there is an easy way to do this in Python? Thanks in advance for the help, --Leo

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  • Automatically check for Security Updates on CentOS or Scientific Linux?

    - by Stefan Lasiewski
    We have machines running RedHat-based distros such as CentOS or Scientific Linux. We want the systems to automatically notify us if there are any known vulnerabilities to the installed packages. FreeBSD does this with the ports-mgmt/portaudit port. RedHat provides yum-plugin-security, which can check for vulnerabilities by their Bugzilla ID, CVE ID or advisory ID. In addition, Fedora recently started to support yum-plugin-security. I believe this was added in Fedora 16. Scientific Linux 6 did not support yum-plugin-security as of late 2011. It does ship with /etc/cron.daily/yum-autoupdate, which updates RPMs daily. I don't think this handles Security Updates only, however. CentOS does not support yum-plugin-security. I monitor the CentOS and Scientific Linux mailinglists for updates, but this is tedious and I want something which can be automated. For those of us who maintain CentOS and SL systems, are there any tools which can: Automatically (Progamatically, via cron) inform us if there are known vulnerabilities with my current RPMs. Optionally, automatically install the minimum upgrade required to address a security vulnerability, which would probably be yum update-minimal --security on the commandline? I have considered using yum-plugin-changelog to print out the changelog for each package, and then parse the output for certain strings. Are there any tools which do this already?

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  • Your thoughts on Best Practices for Scientific Computing?

    - by John Smith
    A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

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  • Languages/Methods to Learn for Scientific Computing?:

    - by Zéychin
    I'm a second-semester Junior working towards a Computer Science degree with a Scientific Computing concentration and a Mathematics degree with a concentration on Applied Discrete Mathematics. So, number crunching and such rather than a bunch of regular expressions, interface design, and networking. I've found that I'm not learning new relevant languages from my coursework and am interested in what the community would recommend me to learn. I know as far as programming methods go, I need to learn more about parallelizing programs, but if there's anything else you can recommend, I would appreciate it. Here's a list of the languages with which I am very experienced (web technologies omitted as they barely apply here). Any recommendations for additional languages I should learn would be very much appreciated!: Java C C++ Fortran77/90/95 Haskell Python MATLAB

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  • Scientific notation in Excel

    - by Vojtech R.
    Hi, I need make Number Format like scientific notation, but without E nor e. Just classic like this: (In latex its 2.3\times10^3) Maybe excel doesn't support this format. (I have on mind Number Format - for hundreds numbers - not in math formula)

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