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• Efficient way to store a graph for calculation in Hadoop

  - by user337499

  I am currently trying to perform calculations like clustering coefficient on huge graphs with the help of Hadoop. Therefore I need an efficient way to store the graph in a way that I can easily access nodes, their neighbors and the neighbors' neighbors. The graph is quite sparse and stored in a huge tab separated file where the first field is the node from which an edge goes to the second node in field two. Thanks in advance!

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• Google Maps panTo AND setCenter

  - by Harry

  The default panTo only pans to the edge of the screen. I like setCenter but would like to pan to that point. Any ideas welcome map.setCenter(mymarker.getPoint()); GEvent.trigger(mymarker,"click"); //open the info window

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• how to draw directed edges with "IGraphContentProvider"?

  - by syeed

  Hi, I am using ZEST and RCP to build a graph visalization tool. I used "IGraphContentProvider" and the "LabelProvider" for drawing the grpah. My question is: how can I draw a directed edge between two nodes using IGraphContentProvider? Thanks in advance -syeed

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• Open-source image processing library that supports high level 3D algorithms ?

  - by user363827

  High, I need to do some image manipulations on CT volume images. Mainly segmentations. Which open-source library supports 3D algorithms - Filtering, edge detection, deformable objects and so ? Language is not an issue at the moment. 10x

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• GtkComboBox related qusestion.

  - by PP

  Hello, How to set GtkComboBox default selectio? How to Adjust X, Y location of Drop Down menu of GtkComboBox? I want to display Drop Down menu at the lower edge of GtkComoBox. Also I want to set text color of Selected text in combo box to white. Thank, PP.

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• How do I achieve lossless JPEG joining without truncation of partial MCUs?

  - by Karan

  I am working on a project for which I need to join thousands of JPEG images losslessly (I'm not talking about the Lossless JPEG/JPEG 2000/JPEG-LS formats here). Aforementioned images have varying levels of chroma subsampling (1x1, 1x2, 2x1, 2x2), resulting in varying MCU sizes (8x8, 8x16, 16x8, 16x16 px). However, in any given set of images to be joined together, each image has identical characteristics. For now, let's assume I only have 2 images. Image #1 (I1) is 256x256px in size and #2 (I2) is 239x256px in size. 2x2 subsampling is used such that MCU size is 16x16px. I2 thus obviously has partial MCUs at the right edge, since its width is not evenly divisible by 16. (I've read that so-called 'partial' MCUs actually contain the data for a complete MCU, but the image dimensions instruct the renderer to only display the relevant pixels and ignore/hide the extra ones.) Looking around for tools that could help me accomplish this, I came across a modified version of JpegTran, that contains an experimental lossless crop 'n' drop (cut & paste) feature. All the other apps I encountered that support lossless JPEG editing seem to utilise IJG's (JpegTran) code, so this seemed to be the logical choice. Also, given the sheer number of images, I wanted something that could preferably be run from the command-line so that I could automate the process with a script. Unfortunately, while everything else worked fine, it seems JpegTran truncates the partial MCUs instead of retaining them. Thus in the example above, the final joined image contains all of I1, but only 224x256px of I2. Why 224? because 239 = 14x16+15, which means there are 14 full MCUs along the width, and 1 partial MCU (just 1px short of the complete 16px). The last 15px is what is getting blanked, leading to a 495x256px image with 15px of blank (grey) pixels at the right edge. See images below (shame that imgur re-compresses them): (left )+ (right) = As you can clearly see, the red portion (15px) of I2 has been truncated by JpegTran. If the MCUs were 8px in width, the lost portion would have been the right-most 7px of I2. Similarly, joining I3 (256x239px) *below * I1 would cause the loss of 7 or 15px, depending on the MCU height of course: (top) + (bottom) = If this is better suited to some other StackExchange (or even non-SE) site/forum where JPEG/image encoding experts hang out, do let me know. Can what I am attempting even be done, or is the so-called 'lossless' JPEG crop 'n' drop only valid for images with no partial MCUs? (Maybe that is why the feature is still in an "experimental state" more than a decade after being introduced...) Until I know for sure that it is impossible, I am not interested in suggestions for lossy joining. Avoiding any generational loss whatsoever is the sole reason why I'm breaking my head over this, else I'd have had this done and dusted ages ago. Also, I am not interested in suggestions related to switching image formats. I do not control the source of the images. If it can be done, how? Please keep in mind that any alternate apps suggested must ideally be capable of automation, given the requirements stated above. (But given how it's unlikely I'm even going to receive a useful answer given the constraints, I would be happy with any app suggestion just as long as it actually works. I can always look into an AutoIT/AHK script or something later to automate it.) I understand that an odd-sized final image might cause issues, so I am fully prepared to accept any solution, even if it results in blank (preferably black) padding pixels to the right/bottom. What I mean is, I don't care if I1 + I2 is 496x256px (1px padding) or even 512x256px (17px padding) in size, as long as the final image contains all the actual image data from both source images, and the entire process is lossless. Obviously the lesser the padding (if any), the better, but at this point any solution will do. A Windows-based solution would be perfect, but a Linux-based one would be entirely acceptable.

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• usb mouse/keyboard doesn't work with 3.11.0-12-generic kernel

  - by x-yuri

  I can't use my usb keyboard/mouse after upgrade from raring to saucy. The keyboard works in grub menu and if I boot with the previous kernel version (3.8.0-31-generic). My new kernel version is 3.11.0-12-generic. I've got Mad Catz R.A.T.7 wired USB mouse, Canyon CNL-MBMSO02 wired usb mouse and Logitech diNovo Edge wireless keyboard, connected to computer through Logitech Unifying Receiver. Using PS/2 keyboard I've managed to get some information. dmesg says: [ 0.166273] ACPI: bus type USB registered [ 0.166273] usbcore: registered new interface driver usbfs [ 0.166273] usbcore: registered new interface driver hub [ 0.166273] usbcore: registered new device driver usb ... [ 3.534226] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver [ 3.534228] ehci-pci: EHCI PCI platform driver [ 3.534291] ehci-pci 0000:00:1a.7: setting latency timer to 64 [ 3.534299] ehci-pci 0000:00:1a.7: EHCI Host Controller [ 3.534304] ehci-pci 0000:00:1a.7: new USB bus registered, assigned bus number 1 [ 3.534315] ehci-pci 0000:00:1a.7: debug port 1 [ 3.538218] ehci-pci 0000:00:1a.7: cache line size of 64 is not supported [ 3.538231] ehci-pci 0000:00:1a.7: irq 18, io mem 0xd3325400 [ 3.548017] ehci-pci 0000:00:1a.7: USB 2.0 started, EHCI 1.00 [ 3.548042] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 [ 3.548045] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.548048] usb usb1: Product: EHCI Host Controller [ 3.548050] usb usb1: Manufacturer: Linux 3.11.0-12-generic ehci_hcd [ 3.548053] usb usb1: SerialNumber: 0000:00:1a.7 [ 3.548155] hub 1-0:1.0: USB hub found [ 3.548159] hub 1-0:1.0: 6 ports detected [ 3.548311] ehci-pci 0000:00:1d.7: setting latency timer to 64 [ 3.548319] ehci-pci 0000:00:1d.7: EHCI Host Controller [ 3.548323] ehci-pci 0000:00:1d.7: new USB bus registered, assigned bus number 2 [ 3.548333] ehci-pci 0000:00:1d.7: debug port 1 [ 3.552228] ehci-pci 0000:00:1d.7: cache line size of 64 is not supported [ 3.552239] ehci-pci 0000:00:1d.7: irq 23, io mem 0xd3325000 [ 3.564014] ehci-pci 0000:00:1d.7: USB 2.0 started, EHCI 1.00 [ 3.564044] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002 [ 3.564047] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.564050] usb usb2: Product: EHCI Host Controller [ 3.564052] usb usb2: Manufacturer: Linux 3.11.0-12-generic ehci_hcd [ 3.564056] usb usb2: SerialNumber: 0000:00:1d.7 [ 3.564163] hub 2-0:1.0: USB hub found [ 3.564167] hub 2-0:1.0: 6 ports detected [ 3.564274] ehci-platform: EHCI generic platform driver [ 3.564280] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver [ 3.564281] ohci-platform: OHCI generic platform driver [ 3.564287] uhci_hcd: USB Universal Host Controller Interface driver [ 3.564345] uhci_hcd 0000:00:1a.0: setting latency timer to 64 [ 3.564347] uhci_hcd 0000:00:1a.0: UHCI Host Controller [ 3.564352] uhci_hcd 0000:00:1a.0: new USB bus registered, assigned bus number 3 [ 3.564378] uhci_hcd 0000:00:1a.0: irq 16, io base 0x0000f0c0 [ 3.564402] usb usb3: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.564404] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.564406] usb usb3: Product: UHCI Host Controller [ 3.564408] usb usb3: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.564410] usb usb3: SerialNumber: 0000:00:1a.0 [ 3.564478] hub 3-0:1.0: USB hub found [ 3.564482] hub 3-0:1.0: 2 ports detected [ 3.564589] uhci_hcd 0000:00:1a.1: setting latency timer to 64 [ 3.564592] uhci_hcd 0000:00:1a.1: UHCI Host Controller [ 3.564597] uhci_hcd 0000:00:1a.1: new USB bus registered, assigned bus number 4 [ 3.564623] uhci_hcd 0000:00:1a.1: irq 21, io base 0x0000f0a0 [ 3.564647] usb usb4: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.564649] usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.564651] usb usb4: Product: UHCI Host Controller [ 3.564653] usb usb4: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.564654] usb usb4: SerialNumber: 0000:00:1a.1 [ 3.564727] hub 4-0:1.0: USB hub found [ 3.564730] hub 4-0:1.0: 2 ports detected [ 3.564834] uhci_hcd 0000:00:1a.2: setting latency timer to 64 [ 3.564837] uhci_hcd 0000:00:1a.2: UHCI Host Controller [ 3.564843] uhci_hcd 0000:00:1a.2: new USB bus registered, assigned bus number 5 [ 3.564863] uhci_hcd 0000:00:1a.2: irq 18, io base 0x0000f080 [ 3.564885] usb usb5: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.564887] usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.564889] usb usb5: Product: UHCI Host Controller [ 3.564891] usb usb5: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.564892] usb usb5: SerialNumber: 0000:00:1a.2 [ 3.564962] hub 5-0:1.0: USB hub found [ 3.564966] hub 5-0:1.0: 2 ports detected [ 3.565073] uhci_hcd 0000:00:1d.0: setting latency timer to 64 [ 3.565076] uhci_hcd 0000:00:1d.0: UHCI Host Controller [ 3.565081] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 6 [ 3.565101] uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000f060 [ 3.565124] usb usb6: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.565127] usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.565128] usb usb6: Product: UHCI Host Controller [ 3.565130] usb usb6: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.565132] usb usb6: SerialNumber: 0000:00:1d.0 [ 3.565195] hub 6-0:1.0: USB hub found [ 3.565198] hub 6-0:1.0: 2 ports detected [ 3.565303] uhci_hcd 0000:00:1d.1: setting latency timer to 64 [ 3.565306] uhci_hcd 0000:00:1d.1: UHCI Host Controller [ 3.565310] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 7 [ 3.565329] uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000f040 [ 3.565352] usb usb7: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.565354] usb usb7: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.565356] usb usb7: Product: UHCI Host Controller [ 3.565358] usb usb7: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.565359] usb usb7: SerialNumber: 0000:00:1d.1 [ 3.565424] hub 7-0:1.0: USB hub found [ 3.565427] hub 7-0:1.0: 2 ports detected [ 3.565534] uhci_hcd 0000:00:1d.2: setting latency timer to 64 [ 3.565537] uhci_hcd 0000:00:1d.2: UHCI Host Controller [ 3.565541] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 8 [ 3.565560] uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000f020 [ 3.565584] usb usb8: New USB device found, idVendor=1d6b, idProduct=0001 [ 3.565587] usb usb8: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.565588] usb usb8: Product: UHCI Host Controller [ 3.565590] usb usb8: Manufacturer: Linux 3.11.0-12-generic uhci_hcd [ 3.565592] usb usb8: SerialNumber: 0000:00:1d.2 [ 3.565658] hub 8-0:1.0: USB hub found [ 3.565661] hub 8-0:1.0: 2 ports detected ... [ 4.120014] usb 2-3: new high-speed USB device number 2 using ehci-pci ... [ 4.468908] usb 2-3: New USB device found, idVendor=046d, idProduct=0825 [ 4.468912] usb 2-3: New USB device strings: Mfr=0, Product=0, SerialNumber=2 [ 4.468914] usb 2-3: SerialNumber: AF582E10 ... [ 5.284019] usb 5-2: new full-speed USB device number 2 using uhci_hcd [ 5.465903] usb 5-2: New USB device found, idVendor=046d, idProduct=0b04 [ 5.465908] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 5.465911] usb 5-2: Product: Logitech BT Mini-Receiver [ 5.465914] usb 5-2: Manufacturer: Logitech [ 5.468948] hub 5-2:1.0: USB hub found [ 5.470898] hub 5-2:1.0: 3 ports detected [ 5.476096] Switched to clocksource tsc [ 5.712099] usb 7-2: new full-speed USB device number 2 using uhci_hcd [ 5.896366] usb 7-2: New USB device found, idVendor=046d, idProduct=c52b [ 5.896370] usb 7-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 5.896372] usb 7-2: Product: USB Receiver [ 5.896374] usb 7-2: Manufacturer: Logitech [ 6.140016] usb 8-1: new full-speed USB device number 2 using uhci_hcd [ 6.324597] usb 8-1: New USB device found, idVendor=0738, idProduct=1708 [ 6.324603] usb 8-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6.324605] usb 8-1: Product: Mad Catz R.A.T.7 Mouse [ 6.324608] usb 8-1: Manufacturer: Mad Catz [ 6.564012] usb 8-2: new low-speed USB device number 3 using uhci_hcd [ 6.746602] usb 8-2: New USB device found, idVendor=1d57, idProduct=0010 [ 6.746608] usb 8-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 6.746610] usb 8-2: Product: usb mouse with wheel [ 6.746613] usb 8-2: Manufacturer: HID-Compliant Mouse [ 7.337898] usb 5-2.2: new full-speed USB device number 3 using uhci_hcd [ 7.490902] usb 5-2.2: New USB device found, idVendor=046d, idProduct=c713 [ 7.490907] usb 5-2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 7.490910] usb 5-2.2: Product: Logitech BT Mini-Receiver [ 7.490913] usb 5-2.2: Manufacturer: Logitech [ 7.490915] usb 5-2.2: SerialNumber: 001F203BD6A7 [ 7.569898] usb 5-2.3: new full-speed USB device number 4 using uhci_hcd [ 7.722901] usb 5-2.3: New USB device found, idVendor=046d, idProduct=c714 [ 7.722906] usb 5-2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 7.722909] usb 5-2.3: Product: Logitech BT Mini-Receiver [ 7.722911] usb 5-2.3: Manufacturer: Logitech [ 7.722913] usb 5-2.3: SerialNumber: 001F203BD6A7 lsusb (more output): Bus 002 Device 002: ID 046d:0825 Logitech, Inc. Webcam C270 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 008 Device 003: ID 1d57:0010 Xenta Bus 008 Device 002: ID 0738:1708 Mad Catz, Inc. Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 005 Device 004: ID 046d:c714 Logitech, Inc. diNovo Edge Keyboard Bus 005 Device 003: ID 046d:c713 Logitech, Inc. Bus 005 Device 002: ID 046d:0b04 Logitech, Inc. Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub More background. Before that I had a problem with logging in to GNOME. During which I upgraded all the packages at one point (apt-get upgrade) and it stopped booting at all (it didn't get to login screen). Then I fixed PATH issue and now I've got this usb-not-working issue. I tried reinstalling kernel, to no effect. Is there anything else I can do to fix or diagnose the problem?

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• Finding the normal of OBB face with an OBB penetrating

  - by Milo

  Below is an illustration: I have an OBB in an OBB (see below for OBB2D code if needed). What I need to determine is, what face it is in, and what direction do I point the normal? The goal is to get the OBB out of the OBB so the normal needs to face outward of the OBB. How could I go about: Finding what face the line is penetrating given the 4 corners of the OBB and the class below: if we define dx=x2-x1 and dy=y2-y1, then the normals are (-dy, dx) and (dy, -dx). Which normal points outward of the OBB? Thanks public class OBB2D { // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(Vector2D center, float w, float h, float angle) { set(center,w,h,angle); } public OBB2D(float left, float top, float width, float height) { set(new Vector2D(left + (width / 2), top + (height / 2)),width,height,0.0f); } public void set(Vector2D center,float w, float h,float angle) { Vector2D X = new Vector2D( (float)Math.cos(angle), (float)Math.sin(angle)); Vector2D Y = new Vector2D((float)-Math.sin(angle), (float)Math.cos(angle)); X = X.multiply( w / 2); Y = Y.multiply( h / 2); corner[0] = center.subtract(X).subtract(Y); corner[1] = center.add(X).subtract(Y); corner[2] = center.add(X).add(Y); corner[3] = center.subtract(X).add(Y); computeAxes(); extents.x = w / 2; extents.y = h / 2; computeDimensions(center,angle); } private void computeDimensions(Vector2D center,float angle) { this.center.x = center.x; this.center.y = center.y; this.angle = angle; boundingRect.left = Math.min(Math.min(corner[0].x, corner[3].x), Math.min(corner[1].x, corner[2].x)); boundingRect.top = Math.min(Math.min(corner[0].y, corner[1].y),Math.min(corner[2].y, corner[3].y)); boundingRect.right = Math.max(Math.max(corner[1].x, corner[2].x), Math.max(corner[0].x, corner[3].x)); boundingRect.bottom = Math.max(Math.max(corner[2].y, corner[3].y),Math.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(new Vector2D(rect.centerX(),rect.centerY()),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0] = corner[1].subtract(corner[0]); axis[1] = corner[3].subtract(corner[0]); // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { axis[a] = axis[a].divide((axis[a].length() * axis[a].length())); origin[a] = corner[0].dot(axis[a]); } } public void moveTo(Vector2D center) { Vector2D centroid = (corner[0].add(corner[1]).add(corner[2]).add(corner[3])).divide(4.0f); Vector2D translation = center.subtract(centroid); for (int c = 0; c < 4; ++c) { corner[c] = corner[c].add(translation); } computeAxes(); computeDimensions(center,angle); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } };

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• SQL University: What and why of database testing

  - by Mladen Prajdic

  This is a post for a great idea called SQL University started by Jorge Segarra also famously known as SqlChicken on Twitter. It’s a collection of blog posts on different database related topics contributed by several smart people all over the world. So this week is mine and we’ll be talking about database testing and refactoring. In 3 posts we’ll cover: SQLU part 1 - What and why of database testing SQLU part 2 - What and why of database refactoring SQLU part 2 – Tools of the trade With that out of the way let us sharpen our pencils and get going. Why test a database The sad state of the industry today is that there is very little emphasis on testing in general. Test driven development is still a small niche of the programming world while refactoring is even smaller. The cause of this is the inability of developers to convince themselves and their managers that writing tests is beneficial. At the moment they are mostly viewed as waste of time. This is because the average person (let’s not fool ourselves, we’re all average) is unable to think about lower future costs in relation to little more current work. It’s orders of magnitude easier to know about the current costs in relation to current amount of work. That’s why programmers convince themselves testing is a waste of time. However we have to ask ourselves what tests are really about? Maybe finding bugs? No, not really. If we introduce bugs, we’re likely to write test around those bugs too. But yes we can find some bugs with tests. The main point of tests is to have reproducible repeatability in our systems. By having a code base largely covered by tests we can know with better certainty what a small code change can break in other parts of the system. By having repeatability we can make code changes with confidence, since we know we’ll see what breaks in other tests. And here comes the inability to estimate future costs. By spending just a few more hours writing those tests we’d know instantly what broke where. Imagine we fix a reported bug. We check-in the code, deploy it and the users are happy. Until we get a call 2 weeks later about a certain monthly process has stopped working. What we don’t know is that this process was developed by a long gone coworker and for some reason it relied on that same bug we’ve happily fixed. There’s no way we could’ve known that. We say OK and go in and fix the monthly process. But what we have no clue about is that there’s this ETL job that relied on data from that monthly process. Now that we’ve fixed the process it’s giving unexpected (yet correct since we fixed it) data to the ETL job. So we have to fix that too. But there’s this part of the app we coded that relies on data from that exact ETL job. And just like that we enter the “Loop of maintenance horror”. With the loop eventually comes blame. Here’s a nice tip for all developers and DBAs out there: If you make a mistake man up and admit to it. All of the above is valid for any kind of software development. Keeping this in mind the database is nothing other than just a part of the application. But a big part! One reason why testing a database is even more important than testing an application is that one database is usually accessed from multiple applications and processes. This makes it the central and vital part of the enterprise software infrastructure. Knowing all this can we really afford not to have tests? What to test in a database Now that we’ve decided we’ll dive into this testing thing we have to ask ourselves what needs to be tested? The short answer is: everything. The long answer is: read on! There are 2 main ways of doing tests: Black box and White box testing. Black box testing means we have no idea how the system internals are built and we only have access to it’s inputs and outputs. With it we test that the internal changes to the system haven’t caused the input/output behavior of the system to change. The most important thing to test here are the edge conditions. It’s where most programs break. Having good edge condition tests we can be more confident that the systems changes won’t break. White box testing has the full knowledge of the system internals. With it we test the internal system changes, different states of the application, etc… White and Black box tests should be complementary to each other as they are very much interconnected. Testing database routines includes testing stored procedures, views, user defined functions and anything you use to access the data with. Database routines are your input/output interface to the database system. They count as black box testing. We test then for 2 things: Data and schema. When testing schema we only care about the columns and the data types they’re returning. After all the schema is the contract to the out side systems. If it changes we usually have to change the applications accessing it. One helpful T-SQL command when doing schema tests is SET FMTONLY ON. It tells the SQL Server to return only empty results sets. This speeds up tests because it doesn’t return any data to the client. After we’ve validated the schema we have to test the returned data. There no other way to do this but to have expected data known before the tests executes and comparing that data to the database routine output. Testing Authentication and Authorization helps us validate who has access to the SQL Server box (Authentication) and who has access to certain database objects (Authorization). For desktop applications and windows authentication this works well. But the biggest problem here are web apps. They usually connect to the database as a single user. Please ensure that that user is not SA or an account with admin privileges. That is just bad. Load testing ensures us that our database can handle peak loads. One often overlooked tool for load testing is Microsoft’s OSTRESS tool. It’s part of RML utilities (x86, x64) for SQL Server and can help determine if our database server can handle loads like 100 simultaneous users each doing 10 requests per second. SQL Profiler can also help us here by looking at why certain queries are slow and what to do to fix them.   One particular problem to think about is how to begin testing existing databases. First thing we have to do is to get to know those databases. We can’t test something when we don’t know how it works. To do this we have to talk to the users of the applications accessing the database, run SQL Profiler to see what queries are being run, use existing documentation to decipher all the object relationships, etc… The way to approach this is to choose one part of the database (say a logical grouping of tables that go together) and filter our traces accordingly. Once we’ve done that we move on to the next grouping and so on until we’ve covered the whole database. Then we move on to the next one. Database Testing is a topic that we can spent many hours discussing but let this be a nice intro to the world of database testing. See you in the next post.

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• What can cause a DirectAccess IPSec Main Mode Error "no policy configured"

  - by Mike Haboustak

  We have Microsoft's DirectAccess VPN set up on Server 2008 R2 with end-to-edge security, and we're having trouble with the manage-out tunnel. The DirectAccess client has DC/DNS and intranet connectivity, it can ping/rdp/etc to intranet hosts. However connections originating from those same intranet hosts can only intermittently reach the client. At times it works fine, other times it doesn't. When an inbound (intranet to client) connection is attempted there's an IPSec Main Mode failure logged: Event 4653 with a failure reason of "No Policy Configured". I think that it may be related to the state of the intranet (corp) access tunnel, and an overlap in the configured subnets for those polices. I haven't figured out exactly what's different in the scenario where the connection works and where it does not.

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• Does this laptop have high enough specifications for gaming? [closed]

  - by Grant

  Here's the laptop It wouldn't be hardcore gaming, mostly things like the new Deus Ex game, Mirror's Edge, Portal 2, etc... I need to replace my current, broken, laptop and I thought this would be a good opportunity to get to play some of these games. My current laptop is really only lacking in its graphics card. (Intel series 4 chipset) If this laptop isn't good enough, I would really appreciate suggestions. I won't be able to get a desktop, otherwise I would, and I can't spend more than $1000 dollars on my new laptop.

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• Restore monitor detection to one only or restore start menu to bottom

  - by Mark

  I have a co-worker that is no longer able to see his start menu. He used to have it pinned to the left edge of his screen. I tried to troubleshoot it a bit and discovered if we do Windows + R then "cmd" [enter] the command prompt opens (but we don't see the start menu or run box), meaning the start menu is somewhere, just off screen. Restarting doesn't help. Is there some way to force Windows to think it only has a single monitor? It seems to "think" it has two but there's only one and we can get the Start menu back. Or, is there a way to restore the start menu to the bottom? Additional info We are able to right-click the desktop for display settings, etc. We can also get into Windows Explorer (via Ctrl + E) so if we need any of that to restore settings we can do it.

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• Restore monitor detection to one only or restore start menu to bottom [Windows 7]

  - by Mark

  I have a co-worker that is no longer able to see his start menu. He used to have it pinned to the left edge of his screen. I tried to troubleshoot it a bit and discovered if we do Windows + R then "cmd" [enter] the command prompt opens (but we don't see the start menu or run box), meaning the start menu is somewhere, just off screen. Restarting doesn't help. Is there some way to force Windows to think it only has a single monitor? It seems to "think" it has two but there's only one and we can get the Start menu back. Or, is there a way to restore the start menu to the bottom? Additional info We are able to right-click the desktop for display settings, etc. We can also get into Windows Explorer (via Ctrl + E) so if we need any of that to restore settings we can do it.

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• Cannot Access Web Interface on HP 2510G

  - by Stephen

  I am currently setting up a new infrastructure with HP 2510s as edge switches and an HP E5406 as the main switch. I also have a DHCP and DNS server running on the same network. When i first set up one of my 2510 switches, I gave it a static IP through the console and then went to the web interface to continue my configuration. Later, I realized that I assigned it the wrong IP address, so i went through the web interface and changed the IP address to the correct one. Now, I can't access the web interface. I can telnet to the switch on the new IP address, but the web interface will not load. If I switch from static IP to DHCP, it loads the web interface. Any ideas on what could be causing the web server in the 2510 not to load with the new static IP address?

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• What is the best distro to host a KVM virtualization solution

  - by elventear

  I am looking for a Server oriented distro that we can expect have decent support but also offer as much as possible some of the latest features that KVM might offer. I am leaning towards Ubuntu LTS 10.04, because well it's LTS and more bleeding edge, but I find Ubuntu not serious enough in terms of support (I say this a heavy Ubuntu user). Given that Centos 6 is not out yet, I am not sure if going Centos 5 would be the best option in terms of getting more features from KVM. Any other distro you would recommend that could meet the criteria of long term support? (At least 4 years)

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• Why does 1080p through a VGA cable fit my HDTV but is oversized when through an HDMI cable?

  - by GraemeF

  I have put together a new PC with a XFX GeForce GTX 260 graphics card and have it connected to my HDTV. First, I used an old VGA cable with a DVI to VGA adapter and plugged it in to my HDTV's VGA port. Running at 1920x1080 it fit the screen perfectly. Now, to avoid running another cable across the room, I have connected it with a DVI to HDMI cable to my TV's HDMI port, and the desktop at 1920x1080 is cropped by the edge of the screen. I have "fixed" the cropping by using NVIDIA's "Adjust desktop size and position" tool, which created a screen resolution of 1814x1022 to fit the screen, but this is no longer the TV's native resolution and confuses some software (e.g. WoW). Why does VGA work as expected, but HDMI is scaled up? Can it be avoided?

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• check_mk IPMI PCM sensor reading randomly fails

  - by Julian Kessel

  I use check_mk_agent for monitoring a server with IPMI and the freeipmi-tools installed. As far as I can see, the monitoring randomly detects no value returned by the IPMI Sensor "Temperature_PCH_Temp". That's a problem since it results in a CRITICAL state triggering a notification. The interruption lasts only over one check, the following is always OK. The temperature is in no edge area and neither the readings before the fail nor after show a Temp that is tending to overrun a treshold. Has someone an idea on what could be the reason for this behaviour and how prevent it?

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• Are there any FIPS-140-2 certified solutions for Linux?

  - by Mark Renouf

  I'm not even 100% certain what this involves, but my current understanding is this: use of only approved cryptographic algorithms for network traffic (easy, we use SSL and lock down the algorithms to only the really strong ones). Some form of physical data protection, involving disk encryption and physical tamper evident packaging. Obviously we're on our own if we need a tamper-proof product. But what about software for encrpytion. My guess is just using LUKS (although secure) will not be certified because it's open source (gov't seems a bit biased towards proprietary solutions here). Guardian Edge was mentioned by someone, but that appears to be complete Windows-based. So we need something like it, certified FIPS-140 compliant we can use on Linux.

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• Quickly open Windows Mobility Center in Windows 8 "tablet" mode

  - by piyo

  I am using a Surface Pro (2013). I would like to know if there is a quick way to open the Windows Mobility Center desktop program. I like to use this program because it is easy to manipulate during the "tablet" (non-keyboard, no-mouse) mode. This program has multiple ways to be started, according to From How to Open and Use Mobility Center in Windows 7 and Windows 8: (Windows 8) Press Windows key + X and select Mobility Center Open the Control Panel and select "Windows Mobility Center" Open the Run dialog and type "mblctr.exe" and press Enter key. None of these are quick and easy when in "tablet" mode. I would ideally like to swipe from right screen edge into to open the Settings pop up and select one icon that opens the Mobility Center. Alternatively, another way I would like to have implemented would be to touch the Windows icon on the tablet screen outside of the viewing area and touch an "app" to launch the Mobility Center. Alternatively, it would be nice to have a Live Tile App that duplicates this functionality.

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• How can I adapt a Dell 2001FP stand for use on newer Dell monitors?

  - by user26453

  I find myself really disappointed with how little vertical adjustment newer Dell LCD's have. I retiring a malfunctioning Dell 2001FP. The stand on the 2001FP allows over 6 inches of vertical adjustment. Compare this to my newer monitors, a 2005FP and a SW22209, both of which allow at most 2 inches of vertical adjustment. So while the Dell 2001FP monitor is shot, the stand is not. Is there anyway to fit the stand onto the SW2209 or the 2005FP? The 2001FP stand seems to have an odd plate with three tabs on the top edge. Can I replace this?

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• Fullscreen Video stutters on second monitor laptop

  - by nobrandheroes

  Fullscreen video on my new 1080p monitor is choppy when it comes from my laptop. The same video plays when not full screen. This goes for all video(Flash/MKV, etc), regardless of video resolution. I have an ATI Mobility Radeon HD 4200 Series card in my Thinkpad Edge, Turion X2 2GHz. The computer plays 1080p fine. Things I've tried: Updating Drivers Switching cables Turning Hardware Acceleration Changing video players process priority Rebooting Turning of laptop screen Turning off unused processes Nothing Works. What is the likelyhood that my laptop cannot power a 1920x1280 display?

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• How backward compatible are the HSDPA mobile networks

  - by Chris Kimpton

  Hi, I have got this Huawei wifi device, which has been unlocked for other networks. Works fine in UK on Vodafone (as well as 3). We are trying to get it to work with the Claro network in Jamaica. It connects and stays connected, but fails to get a 3g connection, just the slow EDGE one. Claro support say its because Claro currently does not support the 2100MHz frequency for 3G, which is what the device uses Does that sound correct? They say I need one that: Ensure however that these devices can use the 850MHz frequency. My understanding was that the device supports up to 2100, including their 850mhz... I am thinking that maybe the APN is incorrect, but I have set it to the only value I can find on the net, namely: internet.ideasclaro.com.jm Thanks in advance, Chris

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• Raid HDD Boot up

  - by user234695

  My server is Power Edge 1950 running server 2008 32Bit, using 3 Physical SAS HDD as a Virtual 2 Disk configured for RAID5, with partition of C drive as OS and D drive as Data. Planning to format and install Server 2008 R2 64Bit so I insert a New Physical disk and configured as RAID5 and clone the C drive and D drive to the new hard disk. Now I need to test that the new hard disk is able to boot windows and work as expected. How do I test, I am not able to boot the windows by choosing the new harddisk, the bios show only the existing HDD, not the new one. Also, if I remove the old three hard disk, and leave the new harddisk and then am I able to boot the device, if I do this does my existing RAID5 configuration and data on the hard disk still remain.

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• HTTP Range request rejected

  - by Dan

  I am trying to understand why my production environment might be disallowing HTTP RANGE requests. I have a pool of W2K8x64/IIS7 servers behind a pair of Netscaler 9000s. I compose the following request in Fiddler: http://myorigin.example.com/file.flv User-Agent: Fiddler Host: myorigin.example.com Range: bytes=40000-60000 The response looks like: HTTP/1.1 200 OK Cache-Control: public Content-Type: video/x-flv Expires: Thu, 24 Jun 2010 18:23:53 GMT Last-Modified: Sat, 11 Apr 2009 00:16:14 GMT Accept-Ranges: none ETag: f9d5c718-e148-4225-9ca6-d1f91a2a3c08-_633749805744270000 Server: Microsoft-IIS/7.0 Edge-Control: max-age=2592000 X-Powered-By: ASP.NET Date: Tue, 25 May 2010 18:23:53 GMT Content-Length: 443668 "Accept-Ranges: none" tells me that the range request was rejected, but I am not sure where/why as IIS7 accepts Range by default. Could the 'scalers be shooting it down? Thanks, Dan

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• How to adjust Aspect Ratio in Windows Media Center

  - by Svish

  Is there any way of adjusting the aspect ratio of movies I view in Windows Media Center on Windows 7 RTM x64? Any hidden features? Any brilliant light weight plugins? Using Shark007 Codecs, and otherwise just default Media Center and Media Player. I know I could reprocess the videos, but that would probably ruin the already bad quality. I also know I could use VLC media player, but I really would like to find a solution that works in Media Center, since VLC media player isn't especially Remote Control and media collection friendly... Update: By the way, I know I can Ctrl+Drag an edge of the media center in window mode and change the aspect ratio of the player, but that doesn't do anything to the video.

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