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  • Skynet Big Data Demo Using Hexbug Spider Robot, Raspberry Pi, and Java SE Embedded (Part 4)

    - by hinkmond
    Here's the first sign of life of a Hexbug Spider Robot converted to become a Skynet Big Data model T-1. Yes, this is T-1 the precursor to the Cyberdyne Systems T-101 (and you know where that will lead to...) It is demonstrating a heartbeat using a simple Java SE Embedded program to drive it. See: Skynet Model T-1 Heartbeat It's alive!!! Well, almost alive. At least there's a pulse. We'll program more to its actions next, and then finally connect it to Skynet Big Data to do more advanced stuff, like hunt for Sara Connor. Java SE Embedded programming makes it simple to create the first model in the long line of T-XXX robots to take on the world. Raspberry Pi makes connecting it all together on one simple device, easy. Next post, I'll show how the wires are connected to drive the T-1 robot. Hinkmond

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  • CUPS causes printer to click and doesn't print

    - by Pez Cuckow
    I'm suffering a strange problem with my Cannon iP4850 when trying to use CUPS on a Raspberry Pi (this is not RPi specific, please do not vote to move it). When I plug the printer into my Laptop (OSX) or my Desktop W7 it identifies as a iP4800 and prints perfectly. So I plug it into the Pi (running debian), set it up in CUPS enable sharing and can now see the iP4800 series shared on the network. However if I print to it (using AirPrint etc...); the file gets to CUPS safely (shows in the queue) but when it tries to print the printer clicks (like a loud thunk) 3/4 times and then gives in, with a double amber flashing light. In cups it shows as job completed. Do you know why using the pi and cups would cause what appears to be a hardware fault and what I can do to fix the problem or to provide further debug info? Thanks for your time! Description: Canon iP4800 series Location: Lounge Driver: Canon PIXMA iP4800 - CUPS+Gutenprint v5.2.9 (color, 2-sided printing) Connection: usb://Canon/iP4800%20series?serial=2239B2 Note: I've tried deleting and re-adding the printer to the Laptop, Desktop and PI and the results are always the same Log for plugging in printer and printing (attempting to) something until the printer turned off again pi@pezpi /var/log $ dmesg [ 7284.176336] usb 1-1.2: new high speed USB device number 8 using dwc_otg [ 7284.279703] usb 1-1.2: New USB device found, idVendor=04a9, idProduct=10d5 [ 7284.279750] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 7284.279771] usb 1-1.2: Product: iP4800 series [ 7284.279786] usb 1-1.2: Manufacturer: Canon [ 7284.279800] usb 1-1.2: SerialNumber: 2239B2 Setting cups to verbose: Change loglevel in cupsd.conf to debug (or debug2) pi@pezpi /var/log $ sudo vim /etc/cups/cupsd.conf pi@pezpi /var/log $ sudo /etc/init.d/cups restart [ ok ] Restarting Common Unix Printing System: cupsd. pi@pezpi /var/log $ Log from $ /var/log/cups/error_log is at http://pastebin.com/7VZMRMrG (too large to post here) The log contains - in order (deleted the log and then did the beneath) Restarting the cups server Attempting to print a test page x2 Printing from 192.168.1.90 via AirPrint Printing from 192.168.1.90 via Network Print Turning the printer off and on again

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  • Rasbperry Pi Mod Offers One Button Audiobook Playback

    - by Jason Fitzpatrick
    How do you design an audiobook player for an elderly book lover who doesn’t want to wrestle with new technology? Simple and with a single button interface is a great place to start. This clever and thoughtful build comes to us courtesy of tinker Michael Clemens. His wife’s grandmother, in her 90s, is visually impaired but still loves to take in books via audiobooks. In an effort to make modern MP3 audiobooks accessible to her, Michael built a dedicated audiobook reader based off Rasbperry Pi and programmed it to use a single button. The system boots, loads the audiobook it finds on the attached USB drive, and loads up its track position from memory. Press the button to resume play or, for a refresher, hold the button for four seconds to start the track over. While you may not be in the market for a one-button audiobook player for an elderly relative, the same simple design could be easily adopted, via new scripts, to another function. Hit up the link below to read more about the build. The One Button Audiobook Player [via Hack A Day] How To Play DVDs on Windows 8 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives?

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  • Raspberry Pi: mvoe home & var folders to USB HDD?

    - by doni49
    I have a Raspberry Pi running raspian. I've installed Apache2, PHP & MySQL. Apache & MySQL are both configured to use sub-directories of /var. I'd like to use a directory on my USB HDD instead of my SD card. I'd also like to move the /home directory to the USB HDD. I'd like to avoid re-partioning my HDD if possible. I thought maybe I could use a symlink to tell raspian that /var is really at /media/USBHDD1/var and /home is really at /media/USBHDD1/home. I tried it last night but couldn't get it to work.

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  • FAQ: GridView Calculation with JavaScript - Editable Price Field

    - by Vincent Maverick Durano
    Recently I wrote a series of blog posts that demonstrates how to do calculation in GridView using JavaScripts. You can check the series of posts below: FAQ: GridView Calculation with JavaScript FAQ: GridView Calculation with JavaScript - Formatting and Validation FAQ: GridView Calculation with JavaScript - Displaying Quantity Total Recently a user in the forums is asking how to calculate the total quantity, sub-totals and total amout in GridView  when a user enters the price and quantity in the TextBox field. Obviously the series of post  that I wrote will not work in this case because the price field in those examples are Label (read-only) and not TextBox fields. In this post I'm going to demonstrate how to accomplish this using the same method used in my previous examples. Basically I'm just going to modify the GridView declaration and replace the Label price field with a TextBox so that users can type on it. And finally modify the CalculateTotals() javascript function. Here are the code blocks below: <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title></title> <script type="text/javascript"> function CalculateTotals() { var gv = document.getElementById("<%= GridView1.ClientID %>"); var tb = gv.getElementsByTagName("input"); var lb = gv.getElementsByTagName("span"); var sub = 0; var total = 0; var indexQ = 1; var indexP = 0; var price = 0; var qty = 0; var totalQty = 0; var tbCount = tb.length / 2; for (var i = 0; i < tbCount; i++) { if (tb[i].type == "text") { ValidateNumber(tb[i + indexQ]); sub = parseFloat(tb[i + indexP].value) * parseFloat(tb[i + indexQ].value); if (isNaN(sub)) { lb[i].innerHTML = "0.00"; sub = 0; } else { lb[i].innerHTML = FormatToMoney(sub, "$", ",", "."); ; } if (isNaN(tb[i + indexQ].value) || tb[i + indexQ].value == "") { qty = 0; } else { qty = tb[i + indexQ].value; } totalQty += parseInt(qty); total += parseFloat(sub); indexQ++; indexP++; } } lb[lb.length - 2].innerHTML = totalQty; lb[lb.length -1].innerHTML = FormatToMoney(total, "$", ",", "."); } function ValidateNumber(o) { if (o.value.length > 0) { o.value = o.value.replace(/[^\d]+/g, ''); //Allow only whole numbers } } function isThousands(position) { if (Math.floor(position / 3) * 3 == position) return true; return false; }; function FormatToMoney(theNumber, theCurrency, theThousands, theDecimal) { var theDecimalDigits = Math.round((theNumber * 100) - (Math.floor(theNumber) * 100)); theDecimalDigits = "" + (theDecimalDigits + "0").substring(0, 2); theNumber = "" + Math.floor(theNumber); var theOutput = theCurrency; for (x = 0; x < theNumber.length; x++) { theOutput += theNumber.substring(x, x + 1); if (isThousands(theNumber.length - x - 1) && (theNumber.length - x - 1 != 0)) { theOutput += theThousands; }; }; theOutput += theDecimal + theDecimalDigits; return theOutput; } </script> </head> <body> <form id="form1" runat="server"> <asp:gridview ID="GridView1" runat="server" ShowFooter="true" AutoGenerateColumns="false"> <Columns> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Description" HeaderText="Item Description" /> <asp:TemplateField HeaderText="Item Price"> <ItemTemplate> <asp:TextBox ID="TXTPrice" runat="server" onkeyup="CalculateTotals();"></asp:TextBox> </ItemTemplate> <FooterTemplate> <b>Total Qty:</b> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Quantity"> <ItemTemplate> <asp:TextBox ID="TXTQty" runat="server" onkeyup="CalculateTotals();"></asp:TextBox> </ItemTemplate> <FooterTemplate> <asp:Label ID="LBLQtyTotal" runat="server" Font-Bold="true" ForeColor="Blue" Text="0" ></asp:Label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b>Total Amount:</b> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Sub-Total"> <ItemTemplate> <asp:Label ID="LBLSubTotal" runat="server" ForeColor="Green" Text="0.00"></asp:Label> </ItemTemplate> <FooterTemplate> <asp:Label ID="LBLTotal" runat="server" ForeColor="Green" Font-Bold="true" Text="0.00"></asp:Label> </FooterTemplate> </asp:TemplateField> </Columns> </asp:gridview> </form> </body> </html>   That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,GridView,JavaScript

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  • 3D Vector "End Point" Calculation for procedural Vector Graphics

    - by FrostFlame64
    Alright, So I need some help with some Vector Math. I've developing some game Engines that have Procedural Fractal Generation for Some Graphics, such as using Lindenmayer Systems for generating Trees and Plants. L-Systems, are drawn by using Turtle Graphics, which is a form of Vector graphics. I first created a system to draw in 2D Graphics, which works perfectly fine. But now I want to make a 3D equivalent, and I’ve run into an issue. For my 2D Version, I created a Method for quickly determining the “End Point” of a Vector-like movement. Given a starting point (X, Y), a direction (between 0 and 360 degrees), and a distance, the end point is calculated by these formulas: newX = startX + distance * Sin((PI * direction) / 180) newY = startY + distance * Cos((PI * direction) / 180) Now I need something Similarly Equivalent for performing this Calculation in 3D, But I haven’t been able to Google anything that could show me how to do this. I'm flexible enough to get whatever required information is needed for this method calculation, in any reasonable form (Vector3, Quaternion, ect). To summarize: Given a starting point/vector position in 3D space (X, Y, Z), a Direction in 3D space (Vector3, Quaternion, ect), and a Distance, I need to find the “End Point” in 3D Space. Thank you for your time and help.

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  • HPCM 11.1.2.x - Outline Optimisation for Calculation Performance

    - by Jane Story
    When an HPCM application is first created, it is likely that you will want to carry out some optimisation on the HPCM application’s Essbase outline in order to improve calculation execution times. There are several things that you may wish to consider. Because at least one dense dimension for an application is required to deploy from HPCM to Essbase, “Measures” and “AllocationType”, as the only required dimensions in an HPCM application, are created dense by default. However, for optimisation reasons, you may wish to consider changing this default dense/sparse configuration. In general, calculation scripts in HPCM execute best when they are targeting destinations with one or more dense dimensions. Therefore, consider your largest target stage i.e. the stage with the most assignment destinations and choose that as a dense dimension. When optimising an outline in this way, it is not possible to have a dense dimension in every target stage and so testing with the dense/sparse settings in every stage is the key to finding the best configuration for each individual application. It is not possible to change the dense/sparse setting of individual cloned dimensions from EPMA. When a dimension that is to be repeated in multiple stages, and therefore cloned, is defined in EPMA, every instance of that dimension has the same storage setting. However, such manual changes may not be preserved in all cases. Please see below for full explanation. However, once the application has been deployed from EPMA to HPCM and from HPCM to Essbase, it is possible to make the dense/sparse changes to a cloned dimension directly in Essbase. This can be done by editing the properties of the outline in Essbase Administration Services (EAS) and manually changing the dense/sparse settings of individual dimensions. There are two methods of deployment from HPCM to Essbase from 11.1.2.1. There is a “replace” deploy method and an “update” deploy method: “Replace” will delete the Essbase application and replace it. If this method is chosen, then any changes made directly on the Essbase outline will be lost. If you use the update deploy method (with or without archiving and reloading data), then the Essbase outline, including any manual changes you have made (i.e. changes to dense/sparse settings of the cloned dimensions), will be preserved. Notes If you are using the calculation optimisation technique mentioned in a previous blog to calculate multiple POVs (https://blogs.oracle.com/pa/entry/hpcm_11_1_2_optimising) and you are calculating all members of that POV dimension (e.g. all months in the Period dimension) then you could consider making that dimension dense. Always review Block sizes after all changes! The maximum block size recommended in the Essbase Database Administrator’s Guide is 100k for 32 bit Essbase and 200k for 64 bit Essbase. However, calculations may perform better with a larger than recommended block size provided that sufficient memory is available on the Essbase server. Test different configurations to determine the most optimal solution for your HPCM application. Please note that this blog article covers HPCM outline optimisation only. Additional performance tuning can be achieved by methodically testing database settings i.e data cache, index cache and/or commit block settings. For more information on Essbase tuning best practices, please review these items in the Essbase Database Administrators Guide. For additional information on the commit block setting, please see the previous PA blog article https://blogs.oracle.com/pa/entry/essbase_11_1_2_commit

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  • Time calculation between openGL update calls.

    - by Vijayendra
    In XNA, the system calls update and draw function with the time information. This contains information such as how much time has passed since last update was called. This makes easy to integrate time and do animation calculation accordingly. But I dont see any such mechanism in openGL. I see openGL requires programmers to have their own implementation which could be buggy or inefficient. Is there any standard (and efficient) code that demonstrate this practice in openGL?

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  • A Skill Testing (Search Engine) Calculation

    - by Ken Cox [MVP]
    To claim a contest prize, I had to answer the following skill-testing question: 1000 - 50 / 2 x 10 Okay, it’s not a problem as long as you know about operator precedence. As a developer, my brain automatically supplied brackets. I was curious as to whether this exact skill-testing question is commonly-used in online contests, so I Googled the formula. To my amazement, Google returned the result of the calculation – complete with brackets: 1 000 - ((50 / 2) x 10) = 750 (Google) Bing also has a calculator...(read more)

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  • How do I determine whether calculation was completed, or detect interrupted calculation?

    - by BenTobin
    I have a rather large workbook that takes a really long time to calculate. It used to be quite a challenge to get it to calculate all the way, since Excel is so eager to silently abort calculation if you so much as look at it. To help alleviate the problem, I created some VBA code to initiate the the calculation, which is initiated by a form, and the result is that it is not quite as easy to interrupt the calculation process, but it is still possible. (I can easily do this by clicking the close X on the form, but I imagine there are other ways) Rather than taking more steps to try and make it harder to interrupt calculation, I'd like to have the code detect whether calculation is complete, so it can notify the user rather than just blindly forging on into the rest of the steps in my code. So far, I can't find any way to do that. I've seen references to Application.CalculationState, but the value is xlDone after I interrupt calculation, even if I interrupt the calculation after a few seconds (it normally takes around an hour). I can't think of a way to do this by checking the value of cells, since I don't know which one is calculated last. I see that there is a way to mark cells as "dirty" but I haven't been able to find a way to check the dirtiness of a cell. And I don't know if that's even the right path to take, since I'd likely have to check every cell in every sheet. The act of interrupting calculation does not raise an error, so my ON ERROR doesn't get triggered. Is there anything I'm missing? Any ideas? Any ideas?

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  • Raspberry Pi based Hadoop cluster

    - by Dmitriy Sukharev
    Is it at least possible to build Hadoop cluster from Raspberry Pi-based nodes? Can such a cluster meet hardware requirements of Hadoop? And if so, how much Raspberry Pi nodes are required to meet requirements? I understand that a cluster from several Raspberry Pi nodes being cheap is not powerful. My purpose is to organize cluster without possibility of loosing personal data from my desktop or notebook, and to use this cluster studying Hadoop. I'd appreciate if you suggest any better ideas of organizing a cheap Hadoop cluster for studying purposes. UPD: I've seen that recommended amount of memory for Hadoop is 16-24GB, multi-core processors, and 1TB of HDD, but it doesn't look like minimal requirements.

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  • How often do CPUs make calculation errors?

    - by veryfoolish
    In Dijkstra's Notes on Structured Programming he talks a lot about the provability of computer programs as abstract entities. As a corollary, he remarks how testing isn't enough. E.g., he points out the fact that it would be impossible to test a multiplication function f(x,y) = x*y for any large values of x and y across the entire ranges of x and y. My question concerns his misc. remarks on "lousy hardware". I know the essay was written in the 1970s when computer hardware was less reliable, but computers still aren't perfect, so they must make calculation mistakes sometimes. Does anybody know how often this happens or if there are any statistics on this?

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  • A correct way for JAVA age calculation? [closed]

    - by Jhonnytunes
    I have already a Java calculation of age method. I have a Person Class where I have the method and I need to ask the current time each time the method is called. All I could do is make age a static field of person class, so all person classes use the same time now. Im worring about the Calendar.get() creating Calendar objects every time method is called. Am I doing it wrong? Can I make it better? public short getAge(){ now = Calendar.getInstance(); return (short) ( (now.getTimeInMillis() - birthDate.getTimeInMillis())/ 31536000000L); }

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  • How often do CPUs make calculation errors?

    - by veryfoolish
    In Dijkstra's Notes on Structured Programming he talks a lot about the provability of computer programs as abstract entities. As a corollary, he remarks how testing isn't enough. E.g., he points out the fact that it would be impossible to test a multiplication function f(x,y) = x*y for any large values of x and y across the entire ranges of x and y. My question concerns his misc. remarks on "lousy hardware". I know the essay was written in the 1970s when computer hardware was less reliable, but computers still aren't perfect, so they must make calculation mistakes sometimes. Does anybody know how often this happens or if there are any statistics on this?

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  • Socket stops communicating

    - by user1392992
    I'm running python 2.7 code on a Raspberry Pi that receives serial data from an Arduino, processes it, and sends it to a Windows box over a wifi link. The Pi is wired to a Linksys router running in client bridge mode and that router connects over wifi to another Linksys router to which the Windows box is wired. The code in the Pi runs fine for some (apparently) random interval, and then the Pi becomes unreachable from the Windows box. I'm running PUTTY on the the Windows machine to connect to the Pi and when the fail occurs I get a message saying there's been a network error and the Pi is not reachable. Pinging the Pi from the Windows machine works fine until the error, at which time it produces "Reply from 192.168.0.129: Destination host unreachable." The client bridge router to which the Pi is connected remains reachable. I've got the networking code on the Pi wrapped in an exception handler, and when it fails it shows the following: Ethernet problem: Traceback (most recent call last): File "garage.py", line 108, in module s.connect((host, port)) File "/usr/lib/python2.7/socket.py", line 224, in meth return getattr(self._sock,name)(*args) error: [Errno 113] No route to host None The relevant python code looks like: import socket import traceback host = '192.168.0.129' port = 31415 in the setup, and after serial data has been processed: try: bline = strline.encode('utf-8') s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, port)) s.send(bline) s.close() except: print "Ethernet problem: " print traceback.print_exc() Where strline contains the processed data. As I said, this runs fine for a few hours more or less before failing. Any ideas? EDIT: When PUTTY fails its error message is :Network Error: Software caused connection abort."

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  • FAQ: GridView Calculation with JavaScript

    - by Vincent Maverick Durano
    In my previous post I wrote a simple demo on how to Calculate Totals in GridView and Display it in the Footer. Basically what it does is it calculates the total amount by typing into the TextBox and display the grand total in the footer of the GridView and basically it was a server side implemenation.  Many users in the forums are asking how to do the same thing without postbacks and how to calculate both amount and total amount together. In this post I will demonstrate how to do this using JavaScript. To get started let's go ahead and set up the form. Just for the simplicity of this demo I just set up the form like this:   <asp:gridview ID="GridView1" runat="server" ShowFooter="true" AutoGenerateColumns="false"> <Columns> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Description" HeaderText="Item Description" /> <asp:TemplateField HeaderText="Item Price"> <ItemTemplate> <asp:Label ID="LBLPrice" runat="server" Text='<%# Eval("Price") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Quantity"> <ItemTemplate> <asp:TextBox ID="TXTQty" runat="server"></asp:TextBox> </ItemTemplate> <FooterTemplate> <b>Total Amount:</b> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Sub-Total"> <ItemTemplate> <asp:Label ID="LBLSubTotal" runat="server"></asp:Label> </ItemTemplate> <FooterTemplate> <asp:Label ID="LBLTotal" runat="server" ForeColor="Green"></asp:Label> </FooterTemplate> </asp:TemplateField> </Columns> </asp:gridview>   As you can see there's no fancy about the mark up above. It just a standard GridView with BoundFields and TemplateFields on it. Now just for the purpose of this demo I just use a dummy data for populating the GridView. Here's the code below:   public partial class GridCalculation : System.Web.UI.Page { private void BindDummyDataToGrid() { DataTable dt = new DataTable(); DataRow dr = null; dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); dt.Columns.Add(new DataColumn("Description", typeof(string))); dt.Columns.Add(new DataColumn("Price", typeof(string))); dr = dt.NewRow(); dr["RowNumber"] = 1; dr["Description"] = "Nike"; dr["Price"] = "1000"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 2; dr["Description"] = "Converse"; dr["Price"] = "800"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 3; dr["Description"] = "Adidas"; dr["Price"] = "500"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 4; dr["Description"] = "Reebok"; dr["Price"] = "750"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 5; dr["Description"] = "Vans"; dr["Price"] = "1100"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 6; dr["Description"] = "Fila"; dr["Price"] = "200"; dt.Rows.Add(dr); //Bind the Gridview GridView1.DataSource = dt; GridView1.DataBind(); } protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { BindDummyDataToGrid(); } } }   Now try to run the page. The output should look something like below: The Client-Side Calculation Here's the code for the GridView calculation:   <script type="text/javascript"> function CalculateTotals() { var gv = document.getElementById("<%= GridView1.ClientID %>"); var tb = gv.getElementsByTagName("input"); var lb = gv.getElementsByTagName("span"); var sub = 0; var total = 0; var indexQ = 1; var indexP = 0; for (var i = 0; i < tb.length; i++) { if (tb[i].type == "text") { sub = parseFloat(lb[indexP].innerHTML) * parseFloat(tb[i].value); if (isNaN(sub)) { lb[i + indexQ].innerHTML = ""; sub = 0; } else { lb[i + indexQ].innerHTML = sub; } indexQ++; indexP = indexP + 2; total += parseFloat(sub); } } lb[lb.length -1].innerHTML = total; } </script>   The code above calculates the sub-total by multiplying the price and the quantity and at the same time calculates the total amount  by adding the sub-total values. Now you can simply call the JavaScript function above like this:   <ItemTemplate> <asp:TextBox ID="TXTQty" runat="server" onkeyup="CalculateTotals();"></asp:TextBox> </ItemTemplate>   Running the code above will display something like below: That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,JavaScript,GridView,TipsTricks

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  • Why wireless adatper stop to work?

    - by AndreaNobili
    today I correctly installed the driver for the TP-LINK TL-WN725N USB wireless adapter on my RaspBerry Pi (I use RaspBian that is a Debian), then I setted up the wifi using the wpa-supplicant as explained in this tutorial: http://www.maketecheasier.com/setup-wifi-on-raspberry-pi/ This worked fine untill this evening. Then suddenly it stopped to work when I try to connect in SSH and the Raspberry is on the wireless (or rather it should be, as this is not in the list of my router's DHCP connected Client) The strange thing is that the USB wirless adapter blink so I think that this is not a driver problem. If I try to connect it by the ethernet I have no problem. It appear in my router's DHCP connected Client and I can connect to it by SSH. When I connect to it using ethernet if I perform an ifconfig command I obtain: pi@raspberrypi ~ $ ifconfig eth0 Link encap:Ethernet HWaddr b8:27:eb:2a:9f:b0 inet addr:192.168.1.9 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:48 errors:0 dropped:0 overruns:0 frame:0 TX packets:59 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6006 (5.8 KiB) TX bytes:8268 (8.0 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1104 (1.0 KiB) TX bytes:1104 (1.0 KiB) wlan0 Link encap:Ethernet HWaddr e8:94:f6:19:80:4c UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) So it seems that the wlan0 USB wireless adapter driver is correctly loaded. If I remove the USB wireless adapter and put it again into the USB port, the lasts lines of dmesg log is: [ 20.303172] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [ 20.306340] RTL871X: set bssid:00:00:00:00:00:00 [ 20.306726] RTL871X: set ssid [g\xffffffc6isQ\xffffffffJ\xffffffec)\xffffffcd\xffffffba\xffffffba\xffffffab\xfffffff2\xfffffffb\xffffffe3F|\xffffffc2T\xfffffff8\x1b\xffffffe8\xffffffe7\xffffff8dvZ.c3\xffffff9f\xffffffc9\xffffff9a\xffffff9aD\xffffffa7\x1a\xffffffa0\x1a\xffffff8b] fw_state=0x00000008 [ 21.614585] RTL871X: indicate disassoc [ 21.908495] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0x45E1 [ 25.006282] Adding 102396k swap on /var/swap. Priority:-1 extents:1 across:102396k SSFS [ 26.247997] RTL871X: nolinked power save enter As you can see some of these line are related to the RTL871X that is my USB wireless adapter, but I don't know is that these line report an error or if it is all ok. Looking at the adapter status I obtain: pi@raspberrypi ~ $ ip link list dev wlan0 3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000 link/ether e8:94:f6:19:80:4c brd ff:ff:ff:ff:ff:ff As you can see the mode is DORMANT but I think that this is normal because now I am connected using ethernet. I tryied to set up the adapter but it seems that I obtain no result, infact: pi@raspberrypi ~ $ sudo ip link set dev wlan0 up pi@raspberrypi ~ $ ip link list dev wlan0 3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000 link/ether e8:94:f6:19:80:4c brd ff:ff:ff:ff:ff:ff pi@raspberrypi ~ $ sudo ip link set dev wlan0 up This is my /etc/network/interfaces file content and it is ok: auto lo iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf iface default inet dhcp and it is the /etc/wpa_supplicant/wpa_supplicant.conf that I think is ok (I did not change it compared to when it worked): ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 network={ ssid="MY-NETWORK" psk="mypassword" key_mgmt=WPA-PSK } and infact if I execute a network scan I correctly find MY-NETWORK in the network list,infact: pi@raspberrypi ~ $ sudo iwlist wlan0 scan | grep ESSID ESSID:"TeleTu_74888B0060AD" ESSID:"MY-NETWORK" ESSID:"FASTWEB-1-PT6NtjL4TOSe" ESSID:"DC" So I reboot the system and I remove the ethernet cable but when I try to connect again to my raspberry I obatin the following error message: andrea@andrea-virtual-machine:~$ sudo ssh [email protected] ssh: connect to host 192.168.1.9 port 22: No route to host It seems that it can't connect using wireless. What could be the problem? What am I missing? How can I solve this situation? Tnx

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  • Nested Entities and calculation on leaf entity property - SQL or NoSQL approach

    - by Chandu
    I am working on a hobby project called Menu/Recipe Management. This is how my entities and their relations look like. A Nutrient has properties Code and Value An Ingredient has a collection of Nutrients A Recipe has a Collection of Ingredients and occasionally can have a collection of other recipes A Meal has a Collection of Recipes and Ingredients A Menu has a Collection of Meals The relations can be depicted as In one of the pages, for a selected menu I need to display the effective nutrients information calculated based on its constituents (Meals, Recipes, Ingredients and the corresponding nutrients). As of now am using SQL Server to store the data and I am navigating the chain from my C# code, starting from each meal of the menu and then aggregating the nutrient values. I think this is not an efficient way as this calculation is being done every time the page is requested and the constituents change occasionally. I was thinking about a having a background service that maintains a table called MenuNutrients ({MenuId, NutrientId, Value}) and will populate/update this table with the effective nutrients when any of the component (Meal, Recipe, Ingredient) changes. I feel that a GraphDB would be a good fit for this requirement, but my exposure to NoSQL is limited. I want to know what are the alternative solutions/approaches to this requirement of displaying the nutrients of a given menu. Hope my description of the scenario is clear.

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  • Raspberry Pi how to format HDD

    - by Speed
    Hi I am very new to Raspberry Pi environment, so looking for a bit of help to format a usb hard disk drive. I ran lsblk and got sda 8:0 0 37.3G 0 disk sda1 8:1 0 37.3G 0 part looking on web, if tried the following "sudo mkfs.ext4 /dev/sda1 -L USB40gb" it did something but when I tried to mount the drive again, it still showed the files that were there before and I can not create new file/folder "Error creating directory: Permission denied" I am writing this from my windows 8.1 pc so can not cut and paste from the pi. trying to format its output is a bit hard. Oh, there is Nothing written after the word "part" above. There use to be /media/USB40gb so I have done something because this has disappeared. I am using PCManFM 0.9.10 It does not have a format option, which would make life a lot easier, but then its not windows. I think I am running the basic linux os for the pi. It boots to a graphic environment, but I do not know how to advise what it is. I think its OpenBox 2.0.4 Thanks in advance Speed PS: I reran the format string above but this time I changed the label to read USB37gb. I did this to confirm that I was in fact formatting the right drive. Low and behold, it actually formatted the drive, wiping everything from it. Great ... testing it by creating a new folder on the drive and get error msg Permission Denied! So I have fixed the formatting issue by trial and error but still can't use the drive... Suggestions anyone?

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  • Round-up: Embedded Java posts and videos

    - by terrencebarr
    I’ve been collecting links to some interesting blog posts and videos related to embedded Java over the last couple of weeks. Passing  these on here: Freescale blog – The Embedded Beat: “Let’s make it real – Internet of Things” Simon Ritter’s blog: “Mind Reading with Raspberry Pi” NightHacking with Steve Chin and Terrence Barr: “Java in the Internet of Things” NightHacking with Steve Chin and Alderan Robotics: “The NAO Robot” Java Magazine: “Getting Started with Java SE for embedded devices on Raspberry Pi” OTN video interview: “Java at ARM TechCon” OPN Techtalk with MX Entertainment: “Using Java and MX’s GrinXML Framework to build Blu-ray Disc and media applications” Oracle PartnerNetwork Blog: “M2M Architecture: Machine to Machine – The Internet of Things – It’s all about the Data” YouTube Java Channel: “Understanding the JVM and Low Latency Applications” Cheers, – Terrence Filed under: Mobile & Embedded Tagged: blog, iot, Java, Java Embedded, Raspberry Pi, video

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  • Round-up: Embedded Java posts and videos

    - by terrencebarr
    I’ve been collecting links to some interesting blog posts and videos related to embedded Java over the last couple of weeks. Passing  these on here: Freescale blog – The Embedded Beat: “Let’s make it real – Internet of Things” Simon Ritter’s blog: “Mind Reading with Raspberry Pi” NightHacking with Steve Chin and Terrence Barr: “Java in the Internet of Things” NightHacking with Steve Chin and Alderan Robotics: “The NAO Robot” Java Magazine: “Getting Started with Java SE for embedded devices on Raspberry Pi” OTN video interview: “Java at ARM TechCon” OPN Techtalk with MX Entertainment: “Using Java and MX’s GrinXML Framework to build Blu-ray Disc and media applications” Oracle PartnerNetwork Blog: “M2M Architecture: Machine to Machine – The Internet of Things – It’s all about the Data” YouTube Java Channel: “Understanding the JVM and Low Latency Applications” Cheers, – Terrence Filed under: Mobile & Embedded Tagged: blog, iot, Java, Java Embedded, Raspberry Pi, video

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  • Any reliable polygon normal calculation code?

    - by Jenko
    I'm currently calculating the normal vector of a polygon using this code, but for some faces here and there it calculates a wrong normal. I don't really know what's going on or where it fails but its not reliable. Do you have any polygon normal calculation that's tested and found to be reliable? // calculate normal of a polygon using all points var n:int = points.length; var x:Number = 0; var y:Number = 0; var z:Number = 0 // ensure all points above 0 var minx:Number = 0, miny:Number = 0, minz:Number = 0; for (var p:int = 0, pl:int = points.length; p < pl; p++) { var po:_Point3D = points[p] = points[p].clone(); if (po.x < minx) { minx = po.x; } if (po.y < miny) { miny = po.y; } if (po.z < minz) { minz = po.z; } } for (p = 0; p < pl; p++) { po = points[p]; po.x -= minx; po.y -= miny; po.z -= minz; } var cur:int = 1, prev:int = 0, next:int = 2; for (var i:int = 1; i <= n; i++) { // using Newell method x += points[cur].y * (points[next].z - points[prev].z); y += points[cur].z * (points[next].x - points[prev].x); z += points[cur].x * (points[next].y - points[prev].y); cur = (cur+1) % n; next = (next+1) % n; prev = (prev+1) % n; } // length of the normal var length:Number = Math.sqrt(x * x + y * y + z * z); // turn large values into a unit vector if (length != 0){ x = x / length; y = y / length; z = z / length; }else { throw new Error("Cannot calculate normal since triangle has an area of 0"); }

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  • Camera frustum calculation coming out wrong

    - by Telanor
    I'm trying to calculate a view/projection/bounding frustum for the 6 directions of a point light and I'm having trouble with the views pointing along the Y axis. Our game uses a right-handed, Y-up system. For the other 4 directions I create the LookAt matrix using (0, 1, 0) as the up vector. Obviously that doesn't work when looking along the Y axis so for those I use an up vector of (-1, 0, 0) for -Y and (1, 0, 0) for +Y. The view matrix seems to come out correctly (and the projection matrix always stays the same), but the bounding frustum is definitely wrong. Can anyone see what I'm doing wrong? This is the code I'm using: camera.Projection = Matrix.PerspectiveFovRH((float)Math.PI / 2, ShadowMapSize / (float)ShadowMapSize, 1, 5); for(var i = 0; i < 6; i++) { var renderTargetView = shadowMap.GetRenderTargetView((TextureCubeFace)i); var up = DetermineLightUp((TextureCubeFace) i); var forward = DirectionToVector((TextureCubeFace) i); camera.View = Matrix.LookAtRH(this.Position, this.Position + forward, up); camera.BoundingFrustum = new BoundingFrustum(camera.View * camera.Projection); } private static Vector3 DirectionToVector(TextureCubeFace direction) { switch (direction) { case TextureCubeFace.NegativeX: return -Vector3.UnitX; case TextureCubeFace.NegativeY: return -Vector3.UnitY; case TextureCubeFace.NegativeZ: return -Vector3.UnitZ; case TextureCubeFace.PositiveX: return Vector3.UnitX; case TextureCubeFace.PositiveY: return Vector3.UnitY; case TextureCubeFace.PositiveZ: return Vector3.UnitZ; default: throw new ArgumentOutOfRangeException("direction"); } } private static Vector3 DetermineLightUp(TextureCubeFace direction) { switch (direction) { case TextureCubeFace.NegativeY: return -Vector3.UnitX; case TextureCubeFace.PositiveY: return Vector3.UnitX; default: return Vector3.UnitY; } } Edit: Here's what the values are coming out to for the PositiveX and PositiveY directions: Constants: Position = {X:0 Y:360 Z:0} camera.Projection = [M11:0.9999999 M12:0 M13:0 M14:0] [M21:0 M22:0.9999999 M23:0 M24:0] [M31:0 M32:0 M33:-1.25 M34:-1] [M41:0 M42:0 M43:-1.25 M44:0] PositiveX: up = {X:0 Y:1 Z:0} target = {X:1 Y:360 Z:0} camera.View = [M11:0 M12:0 M13:-1 M14:0] [M21:0 M22:1 M23:0 M24:0] [M31:1 M32:0 M33:0 M34:0] [M41:0 M42:-360 M43:0 M44:1] camera.BoundingFrustum: Matrix = [M11:0 M12:0 M13:1.25 M14:1] [M21:0 M22:0.9999999 M23:0 M24:0] [M31:0.9999999 M32:0 M33:0 M34:0] [M41:0 M42:-360 M43:-1.25 M44:0] Top = {A:0.7071068 B:-0.7071068 C:0 D:254.5584} Bottom = {A:0.7071068 B:0.7071068 C:0 D:-254.5584} Left = {A:0.7071068 B:0 C:0.7071068 D:0} Right = {A:0.7071068 B:0 C:-0.7071068 D:0} Near = {A:1 B:0 C:0 D:-1} Far = {A:-1 B:0 C:0 D:5} PositiveY: up = {X:0 Y:0 Z:-1} target = {X:0 Y:361 Z:0} camera.View = [M11:-1 M12:0 M13:0 M14:0] [M21:0 M22:0 M23:-1 M24:0] [M31:0 M32:-1 M33:0 M34:0] [M41:0 M42:0 M43:360 M44:1] camera.BoundingFrustum: Matrix = [M11:-0.9999999 M12:0 M13:0 M14:0] [M21:0 M22:0 M23:1.25 M24:1] [M31:0 M32:-0.9999999 M33:0 M34:0] [M41:0 M42:0 M43:-451.25 M44:-360] Top = {A:0 B:0.7071068 C:0.7071068 D:-254.5585} Bottom = {A:0 B:0.7071068 C:-0.7071068 D:-254.5585} Left = {A:-0.7071068 B:0.7071068 C:0 D:-254.5585} Right = {A:0.7071068 B:0.7071068 C:0 D:-254.5585} Near = {A:0 B:1 C:0 D:-361} Far = {A:0 B:-1 C:0 D:365} When I use the resulting BoundingFrustum to cull regions outside of it, this is the result: Pass PositiveX: Drew 3 regions Pass NegativeX: Drew 6 regions Pass PositiveY: Drew 400 regions Pass NegativeY: Drew 36 regions Pass PositiveZ: Drew 3 regions Pass NegativeZ: Drew 6 regions There are only 400 regions to draw and the light is in the center of them. As you can see, the PositiveY direction is drawing every single region. With the near/far planes of the perspective matrix set as small as they are, there's no way a single frustum could contain every single region.

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  • Need help programming with Mclauren series and Taylor series!

    - by user352258
    Ok so here's what i have so far: #include <stdio.h> #include <math.h> //#define PI 3.14159 int factorial(int n){ if(n <= 1) return(1); else return(n * factorial(n-1)); } void McLaurin(float pi){ int factorial(int); float x = 42*pi/180; int i, val=0, sign; for(i=1, sign=-1; i<11; i+=2){ sign *= -1; // alternate sign of cos(0) which is 1 val += (sign*(pow(x, i)) / factorial(i)); } printf("\nMcLaurin of 42 = %d\n", val); } void Taylor(float pi){ int factorial(int); float x; int i; float val=0.00, sign; float a = pi/3; printf("Enter x in degrees:\n"); scanf("%f", &x); x=x*pi/180.0; printf("%f",x); for(i=0, sign=-1.0; i<2; i++){ if(i%2==1) sign *= -1.0; // alternate sign of cos(0) which is 1 printf("%f",sign); if(i%2==1) val += (sign*sin(a)*(pow(x-a, i)) / factorial(i)); else val += (sign*cos(a)*(pow(x-a, i)) / factorial(i)); printf("%d",factorial(i)); } printf("\nTaylor of sin(%g degrees) = %d\n", (x*180.0)/pi, val); } main(){ float pi=3.14159; void McLaurin(float); void Taylor(float); McLaurin(pi); Taylor(pi); } and here's the output: McLaurin of 42 = 0 Enter x in degrees: 42 0.733038-1.00000011.0000001 Taylor of sin(42 degrees) = -1073741824 I suspect the reason for these outrageous numbers goes with the fact that I mixed up my floats and ints? But i just cant figure it out...!! Maybe its a math thing, but its never been a strength of mine let alone program with calculus. Also the Mclaurin fails, how does it equal zero? WTF! Please help correct my noobish code. I am still a beginner...

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