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  • Arbitrary projection matrix from 6 arbitrary frustum planes

    - by Doub
    A projection matrix represent a tranformation from the camera view space to the rendering system clip space. In other words, it defines the transormation between a 6-sided frustum to the clip cube. The glOrtho and glFrustum use only 6 parameter to define such a projection, but impose several constraints on the frustum that will get projected to the clip cube: the near and far planes are parallel, the left and right planes intersect on a vertical line, and the top and bottom planes intersect on a horizontal lines, both lines being parallel to the near and far planes. I'd like to lift these restrictions. So, from the definition of the 6 frustum side planes (in whatever representation you see fit), how can I compute a general projection matrix?

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  • Sort List C# in arbitrary order

    - by Jasper
    I have a C# List I.E. List<Food> x = new List<Food> () ; This list is populated with this class Public class Food { public string id { get; set; } public string idUser { get; set; } public string idType { get; set; } //idType could be Fruit , Meat , Vegetable , Candy public string location { get; set; } } Now i have this unsorted List<Food> list ; which has I.E. 15 elements. There are 8 Vegetable Types , 3 Fruit Types , 1 Meat Types , 1 Candy Types I would sort this so that to have a list ordered in this way : 1° : Food.idType Fruit 2° : Food.idType Vegetables 3° : Food.idType Meat 4° : Food.idType Candy 5° : Food.idType Fruit 6° : Food.idType Vegetables 7° : Food.idType Fruit //Becouse there isnt more Meat so i insert the //next one which is Candy but also this type is empty //so i start from begin : Fruit 8° : Food.idType Vegetables 9° : Food.idType Vegetables // For the same reason of 7° 10 ° Food.idType Vegetables ...... .... .... 15 : Food.idType Vegetables I cant find a rule to do this. Is there a linq or List.Sort instruction which help me to order the list in this way? Update i changed the return value of idType and now return int type instead string so 1=Vegetable , 2=Fruit , 3=Candy 4=Meat

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  • Arbitrary precision arithmetic with Ruby

    - by macek
    How the heck does Ruby do this? Does Jörg or anyone else know what's happening behind the scenes? irb(main):001:0> 999**999 368063488259223267894700840060521865838338232037353204655959621437025609300472231530103873614505175218691345257589896391130393189447969771645832382192366076536631132001776175977932178658703660778465765811830827876982014124022948671975678131724958064427949902810498973271030787716781467419524180040734398996952930832508934116945966120176735120823151959779536852290090377452502236990839453416790640456116471139751546750048602189291028640970574762600185950226138244530187489211615864021135312077912018844630780307462205252807737757672094320692373101032517459518497524015120165166724189816766397247824175394802028228160027100623998873667435799073054618906855460488351426611310634023489044291860510352301912426608488807462312126590206830413782664554260411266378866626653755763627796569082931785645600816236891168141774993267488171702172191072731069216881668294625679492696148976999868715671440874206427212056717373099639711168901197440416590226524192782842896415414611688187391232048327738965820265934093108172054875188246591760877131657895633586576611857277011782497943522945011248430439201297015119468730712364007639373910811953430309476832453230123996750235710787086641070310288725389595138936784715274150426495416196669832679980253436807864187160054589045664027158817958549374490512399055448819148487049363674611664609890030088549591992466360050042566270348330911795487647045949301286614658650071299695652245266080672989921799342509291635330827874264789587306974472327718704306352445925996155619153783913237212716010410294999877569745287353422903443387562746452522860420416689019732913798073773281533570910205207767157128174184873357050830752777900041943256738499067821488421053870869022738698816059810579221002560882999884763252161747566893835178558961142349304466506402373556318707175710866983035313122068321102457824112014969387225476259342872866363550383840720010832906695360553556647545295849966279980830561242960013654529514995113584909050813015198928283202189194615501403435553060147713139766323195743324848047347575473228198492343231496580885057330510949058490527738662697480293583612233134502078182014347192522391449087738579081585795613547198599661273567662441490401862839817822686573112998663038868314974259766039340894024308383451039874674061160538242392803580758232755749310843694194787991556647907091849600704712003371103926967137408125713631396699343733288014254084819379380555174777020843568689927348949484201042595271932630685747613835385434424807024615161848223715989797178155169951121052285149157137697718850449708843330475301440373094611119631361702936342263219382793996895988331701890693689862459020775599439506870005130750427949747071390095256759203426671803377068109744629909769176319526837824364926844730545524646494321826241925107158040561607706364484910978348669388142016838792902926158979355432483611517588605967745393958061959024834251565197963477521095821435651996730128376734574843289089682710350244222290017891280419782767803785277960834729869249991658417000499998999

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  • Enterprise Architecture IS (should not be) Arbitrary

    - by pat.shepherd
    I took a look at a blog entry today by Jordan Braunstein where he comments on another blog entry titled “Yes, “Enterprise Architecture is Relative BUT it is not Arbitrary.”  The blog makes some good points such as the following: Lock 10 architects in 10 separate rooms; provide them all an identical copy of the same business, technical, process, and system requirements; have them design an architecture under the same rules and perspectives; and I guarantee your result will be 10 different architectures of varying degrees. SOA Today: Enterprise Architecture IS Arbitrary Agreed, …to a degree….but less so if all 10 truly followed one of the widely accepted EA frameworks. My thinking is that EA frameworks all focus on getting the business goals/vision locked down first as the primary drivers for decisions made lower down the architecture stack.  Many people I talk to, know about frameworks such as TOGAF, FEA, etc. but seldom apply the tenants to the architecture at hand.  We all seem to want to get right into the Visio diagrams and boxes and arrows and connecting protocols and implementation details and lions and tigers and bears (Oh, my!) too early. If done properly the Business, Application and Information architectures are nailed down BEFORE any technological direction (SOA or otherwise) is set.  Those 3 layers and Governance (people and processes), IMHO, are layers that should not vary much as they have everything to do with understanding the business -- from which technological conclusions can later be drawn. I really like what he went on to say later in the post about the fact that architecture attempts to remove the amount of variance between the 10 different architect’s work.  That is the real heart of what EA is about; REMOVING THE ARBRITRARITY.

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  • CVE-2012-1182 Arbitrary code execution vulnerability in Samba

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-1182 Arbitrary code execution vulnerability 10 Samba Solaris 10 SPARC: 119757-22 x86: 119758-22 Solaris 11 11/11 SRU 7.5 Solaris 9 SPARC: 114684-18 x86: 114685-18 This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • CVE-2012-4245 Arbitrary code execution vulnerability in Gimp

    - by Umang_D
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-4245 Arbitrary code execution vulnerability 6.8 Gimp Solaris 11 11/11 SRU 12.4 Solaris 10 Contact Support This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • Drawing an outline around an arbitrary group of hexagons

    - by Perky
    Is there an algorithm for drawing an outline around around an arbitrary group of hexagons? The polygon outline drawn may be concave. See the images below, the green line is what I am trying to achieve. The hexagons are stored as vertices and drawn as polygons. Edit: I've uploaded images that should explain more. I want to favour convex hulls because it's conveys an area of control more quickly. Each hexagon is stored in a multidimensional array so they all have x and y coordinates, I can easily find adjacent hexagons and the opposite vertex, i.e. adjacentHexagon = getAdjacentHexagon( someHexagon, NORTHWEST ) if there isn't a hexagon immediately adjacent it will continue to search in that direction until it finds one or hits the map edges.

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  • Relative cam movement and momentum on arbitrary surface

    - by user29244
    I have been working on a game for quite long, think sonic classic physics in 3D or tony hawk psx, with unity3D. However I'm stuck at the most fundamental aspect of movement. The requirement is that I need to move the character in mario 64 fashion (or sonic adventure) aka relative cam input: the camera's forward direction always point input forward the screen, left or right input point toward left or right of the screen. when input are resting, the camera direction is independent from the character direction and the camera can orbit the character when input are pressed the character rotate itself until his direction align with the direction the input is pointing at. It's super easy to do as long your movement are parallel to the global horizontal (or any world axis). However when you try to do this on arbitrary surface (think moving along complex curved surface) with the character sticking to the surface normal (basically moving on wall and ceiling freely), it seems harder. What I want is to achieve the same finesse of movement than in mario but on arbitrary angled surfaces. There is more problem (jumping and transitioning back to the real world alignment and then back on a surface while keeping momentum) but so far I didn't even take off the basics. So far I have accomplish moving along the curved surface and the relative cam input, but for some reason direction fail all the time (point number 3, the character align slowly to the input direction). Do you have an idea how to achieve that? Here is the code and some demo so far: The demo: https://dl.dropbox.com/u/24530447/flash%20build/litesonicengine/LiteSonicEngine5.html Camera code: using UnityEngine; using System.Collections; public class CameraDrive : MonoBehaviour { public GameObject targetObject; public Transform camPivot, camTarget, camRoot, relcamdirDebug; float rot = 0; //---------------------------------------------------------------------------------------------------------- void Start() { this.transform.position = targetObject.transform.position; this.transform.rotation = targetObject.transform.rotation; } void FixedUpdate() { //the pivot system camRoot.position = targetObject.transform.position; //input on pivot orientation rot = 0; float mouse_x = Input.GetAxisRaw( "camera_analog_X" ); // rot = rot + ( 0.1f * Time.deltaTime * mouse_x ); // wrapAngle( rot ); // //when the target object rotate, it rotate too, this should not happen UpdateOrientation(this.transform.forward,targetObject.transform.up); camRoot.transform.RotateAround(camRoot.transform.up,rot); //debug the relcam dir RelativeCamDirection() ; //this camera this.transform.position = camPivot.position; //set the camera to the pivot this.transform.LookAt( camTarget.position ); // } //---------------------------------------------------------------------------------------------------------- public float wrapAngle ( float Degree ) { while (Degree < 0.0f) { Degree = Degree + 360.0f; } while (Degree >= 360.0f) { Degree = Degree - 360.0f; } return Degree; } private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; camRoot.transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } float GetOffsetAngle( float targetAngle, float DestAngle ) { return ((targetAngle - DestAngle + 180)% 360) - 180; } //---------------------------------------------------------------------------------------------------------- void OnDrawGizmos() { Gizmos.DrawCube( camPivot.transform.position, new Vector3(1,1,1) ); Gizmos.DrawCube( camTarget.transform.position, new Vector3(1,5,1) ); Gizmos.DrawCube( camRoot.transform.position, new Vector3(1,1,1) ); } void OnGUI() { GUI.Label(new Rect(0,80,1000,20*10), "targetObject.transform.up : " + targetObject.transform.up.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "target euler : " + targetObject.transform.eulerAngles.y.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "rot : " + rot.ToString()); } //---------------------------------------------------------------------------------------------------------- void RelativeCamDirection() { float input_vertical_movement = Input.GetAxisRaw( "Vertical" ), input_horizontal_movement = Input.GetAxisRaw( "Horizontal" ); Vector3 relative_forward = Vector3.forward, relative_right = Vector3.right, relative_direction = ( relative_forward * input_vertical_movement ) + ( relative_right * input_horizontal_movement ) ; MovementController MC = targetObject.GetComponent<MovementController>(); MC.motion = relative_direction.normalized * MC.acceleration * Time.fixedDeltaTime; MC.motion = this.transform.TransformDirection( MC.motion ); //MC.transform.Rotate(Vector3.up, input_horizontal_movement * 10f * Time.fixedDeltaTime); } } Mouvement code: using UnityEngine; using System.Collections; public class MovementController : MonoBehaviour { public float deadZoneValue = 0.1f, angle, acceleration = 50.0f; public Vector3 motion ; //-------------------------------------------------------------------------------------------- void OnGUI() { GUILayout.Label( "transform.rotation : " + transform.rotation ); GUILayout.Label( "transform.position : " + transform.position ); GUILayout.Label( "angle : " + angle ); } void FixedUpdate () { Ray ground_check_ray = new Ray( gameObject.transform.position, -gameObject.transform.up ); RaycastHit raycast_result; Rigidbody rigid_body = gameObject.rigidbody; if ( Physics.Raycast( ground_check_ray, out raycast_result ) ) { Vector3 next_position; //UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); next_position = GetNextPosition( raycast_result.point ); rigid_body.MovePosition( next_position ); } } //-------------------------------------------------------------------------------------------- private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } private Vector3 GetNextPosition( Vector3 current_ground_position ) { Vector3 next_position; // //-------------------------------------------------------------------- // angle = 0; // Vector3 dir = this.transform.InverseTransformDirection(motion); // angle = Vector3.Angle(Vector3.forward, dir);// * 1f * Time.fixedDeltaTime; // // if(angle > 0) this.transform.Rotate(0,angle,0); // //-------------------------------------------------------------------- next_position = current_ground_position + gameObject.transform.up * 0.5f + motion ; return next_position; } } Some observation: I have the correct input, I have the correct translation in the camera direction ... but whenever I attempt to slowly lerp the direction of the character in direction of the input, all I get is wild spin! Sad Also discovered that strafing to the right (immediately at the beginning without moving forward) has major singularity trapping on the equator!! I'm totally lost and crush (I have already done a much more featured version which fail at the same aspect)

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  • Selection of a mesh with arbitrary region

    - by Tigran
    Considering example: I have a mesh(es) on the OpenGL screen and would like to select a part of it (say for delete purpose). There is a clear way to do the selction via Ray Tracing, or via Selection provided by OpenGL itself. But, for my users, considering that meshes can get wired surfaces, I need to implement a selection via a Arbitrary closed region, so all triangles that appears present inside that region has to be selected. To be more clear, here is screen shot: I want all triangles inside black polygon to be selected, identified, whatever in some way. How can I achieve that ?

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  • Dump an arbitrary object To Html String

    - by Michael Freidgeim
    For debugging purposes me and my collegue wanted to dump details of the arbitrary object, and created function that uses LINQPad Dump functionality (thanks to http://stackoverflow.com/a/6035014/52277 and original http://linqpad.uservoice.com/forums/18302-linqpad-feature-suggestions/suggestions/447166-make-dump-extension-method-available-in-visual-s discussion)    public static string DumpToHtmlString<T>(this T objectToSerialize)        {            string strHTML = "";            try            {                var writer = LINQPad.Util.CreateXhtmlWriter(true);                writer.Write(objectToSerialize);                strHTML = writer.ToString();            }            catch (Exception exc)            {                Debug.Assert(false, "Investigate why ?" + exc);            }            return strHTML;        }You will need to add the linqpad executable as a reference in your project.TO DO similar in plain text ,look at https://github.com/ServiceStack/ServiceStack.Text StringExtensions , e.g. JsonSerializer/CsvSerializer or http://objectdumper.codeplex.com/

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  • matrix to transform unit cube to space defined by 8 arbitrary points

    - by aadster
    I asked a question relating to similar to this already, but I think this is a clearer objective of what Im trying to achieve.. or whether its possible at all! Im trying to find a transformation (matrix ideally) which would transform the 8 points of a 3d unit cube to 8 arbitrary points in space. The 8 target points have no known structure. e.g: My gut feeling is that a matrix is unable to provide this xform since the cube faces vertices can be concave.. but are there any other methods of transformation? Thanks!

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  • Split large file, have arbitrary start index number

    - by nEJC
    I do a lot of file manipulation on my system and in one particular batch job I end up with around 16 Gb file. I need to prepare this data into smaller chunks for another process. I split it into 10k lines per file and numeric index, padded to 5 digits split -a 5 -d -l 10000 large_input_file /out_path/out. This way I end up with files named out.00000 out.00001 ... The problem is that this way indexing always starts with 0. Is there a way to set it to arbitrary starting index? man reveals nothing ...

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  • Arbitrary Rotation about a Sphere

    - by Der
    I'm coding a mechanic which allows a user to move around the surface of a sphere. The position on the sphere is currently stored as theta and phi, where theta is the angle between the z-axis and the xz projection of the current position (i.e. rotation about the y axis), and phi is the angle from the y-axis to the position. I explained that poorly, but it is essentially theta = yaw, phi = pitch Vector3 position = new Vector3(0,0,1); position.X = (float)Math.Sin(phi) * (float)Math.Sin(theta); position.Y = (float)Math.Sin(phi) * (float)Math.Cos(theta); position.Z = (float)Math.Cos(phi); position *= r; I believe this is accurate, however I could be wrong. I need to be able to move in an arbitrary pseudo two dimensional direction around the surface of a sphere at the origin of world space with radius r. For example, holding W should move around the sphere in an upwards direction relative to the orientation of the player. I believe I should be using a Quaternion to represent the position/orientation on the sphere, but I can't think of the correct way of doing it. Spherical geometry is not my strong suit. Essentially, I need to fill the following block: public void Move(Direction dir) { switch (dir) { case Direction.Left: // update quaternion to rotate left break; case Direction.Right: // update quaternion to rotate right break; case Direction.Up: // update quaternion to rotate upward break; case Direction.Down: // update quaternion to rotate downward break; } }

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  • Managing arbitrary user permissions under PureFTPd

    - by Sebastián Grignoli
    I need to provide an FTP service that needs to be web-managed in the simplest way possible. My customer wants to create folders and users, and give them read only or read/write access arbitrarily. For example: The folder 'Documents' should be read only for several users, writable for internal users, and invisible for the rest. The folder 'Pictures' should be read only for journalists, writable for associates, and invisible for the rest. The folder 'Media' should be read only, writable or invisible for arbitrary users specified on the admin. There could be a large number of users and folders. I can't find a good way to accomplish that. I thought that I could give each user a home folder and put symlinks for the folders he has read access to, and make the user part of the folder's group when he has write access too, but now I think that this wouldn't work, because with PureFTPd (or ProFTPd) I can only specify the virtual user's mapping to a system user, and only one GUID for each virtual user. My approach requires that I could specify several GUIDs for each user (one by each folder he has write access to). I need to start programming this admin and I still don't know wich approach would work, if any. ¿Any ideas?

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  • Handling window resize with arbitrary aspect ratios

    - by DormoTheNord
    I'm currently making a 2D game using SFML. I want the aspect ratio to be maintained when the user resizes the window. I also want the game to work with any arbitrary aspect ratio (like any media player would). Here is the code I have so far: void os::GameEngine::setCameraViewport() { sf::FloatRect tempViewport; float viewAspectRatio = (float)aspectRatio.x / aspectRatio.y; float screenAspectRatio = (float)gameWindow.getSize().x / gameWindow.getSize().y; if (viewAspectRatio > screenAspectRatio) { // Viewport is wider than screen, fit on X } else if (viewAspectRatio < screenAspectRatio) { // Screen is wider than viewport, fit on Y } else // window aspect ratio matches view aspect ratio { tempViewport.height = 1; tempViewport.width = 1; tempViewport.left = 0; tempViewport.top = 0; } viewport = tempViewport; camera.setViewport(viewport); gameWindow.setView(camera); } The problem is I'm having trouble with the logic to determine the properties of the viewport.

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  • Send arbitrary commands to modem for info

    - by mydoghasworms
    I have a USB 3G data card and modem. According to the supplier, to check the data balance on the account, I must dial a number like *89# (or whatever) from the handset. The device appears as a ppp0 interface in my network devices. How does one go about issuing commands to the modem to send the commands and receive back the information? UPDATE: OK, I found some help here: http://www.linuxquestions.org/questions/linux-hardware-18/sending-at-commands-to-a-sms-modem-372445/, but firstly, there are 3 ttyUSB devices on my system, and I assume that one of them is the 3G modem, but how can I tell? Secondly, trying to echo something to two of them says that the device is busy, which stands to reason, because I am using it to connect to the internet. Some help, please?

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  • Add entries to Nautilus' right-click menu (copy, move to arbitrary directories)

    - by qbi
    Assume I want to copy a file from /home/foo/bar/baz to /opt/quuz/dir1/option3. When I try it with Nautilus, first I have to open the correct directory, copy the file, go to the other directory and paste it there. I was thinking of a better way and old KDE3 versions of Konqueror came to mind. It was possible to right-click on a file. The context menu had an option for copying, moving the file to some default directories. Furthermore you could select any directory under /. So for the above action one would right click on a file, select /opt first, a list of subdirectories will open, select /opt/quuz and so on. Using GNOME there are only two possible values (home and desktop). Is there any way to insert more directories to this context menu in GNOME? Can I copy somehow the behaviour of Konqueror?

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  • Ease Rotate RigidBody2D toward arbitrary angle

    - by Plastic Sturgeon
    I'm trying to make a rigidbody2D circle return to an orientation after a collision. But there is a weird behavior I do not expect - it always orients to the same direction. This is what I call in FixedUpdate(): rotationdifference = -halfPI + rigidbody2D.rotation; rigidbody2D.AddTorque (rotationdifference * ease); I would expect this would rotate 90 degrees (1/2 Pi Radians) off of the neutral axis. But it does not. In fact it performs exactly the same as: rotationdifference = rigidbody2D.rotation; rigidbody2D.AddTorque (rotationdifference * ease); What is going on? How would I be able to set an angle I want it to ease towards, and then have it ease towards it when its not colliding with some other force?

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  • Scaling along an arbitrary axis (Dealing with non-uniform scale)

    - by Jon
    I'm trying to build my own little engine to get more familiar with the concepts of 3D programming. I have a transform class that on each frame it creates a Scaling Matrix (S), a Rotation Matrix from a Quaternion (R) and concatenates them together (S*R). Once i have SR, I insert the translation values into the bottom of the three columns. So i end up with a transformation matrix that looks like: [SR SR SR 0] [SR SR SR 0] [SR SR SR 0] [tx ty tz 1] This works perfectly in all cases except when rotating an object that has a non-uniform scale. For example a unit cube with ScaleX = 4, ScaleY = 2, ScaleZ = 1 will give me a rectangular box that is 4 times as wide as the depth and twice as high as the depth. If i then translate this around, the box stays the same and looks normal. The problem happens whenever I try to rotate this scaled box. The shape itself becomes distorted and it appears as though the Scale factors are affecting the object on the World X,Y,Z axis rather than the local X,Y,Z axis of the object. I've done some pretty extensive research through a variety of textbooks (Eberly, Moller/Hoffman, Phar etc) and there isn't a ton there to go off of. Online, most of the answers say to avoid non-uniform scaling which I understand the desire to avoid it, but I'd still like to figure out how to support it. The only thing I can think off is that when constructing a Scale Matrix: [sx 0 0 0] [0 sy 0 0] [0 0 sz 0] [0 0 0 1] This is scaling along the World Axis instead of the object's local Direction, Up and Right vectors or it's local Z, Y, X axis. Does anyone have any tips or ideas on how to handle construction a transformation matrix that allows for non-uniform scaling and rotation? Thanks!

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  • "Arbitrary" context free grammars?

    - by danwroy
    Long time admirer first time inquirer :) I'm working on a program which derives a deterministic finite-state automata from a context-free grammar, and the paper I have been assigned which explains how to do this keeps referring to "arbitrary probabilistic context-free grammars" but never defines the meaning of "arbitrary" in relation to PCFGs. I assume they mean "any old PCFG" but then why not just say "any PCFG"? The term also turns up in several Wikipedia entries. At the top of the CFG page there is a reference to arbitrariness in relation to CFGs on ("clauses can be nested inside clauses arbitrarily deeply"), but doesn't make clear why someone would refer to a PCFG or subset of PCFGs as arbitrary. In case anyone is curious, the paper is Parsing and Hypergraphs by Klein and Manning (2001); I've also been reading two other papers by them related to this one (An Agenda-Based Chart Parser for Arbitrary Probabilistic Context-Free Grammars and Empirical Bounds, Theoretical Models, and the Penn Treebank) which use the term extensively but never explain it either. Thanks for your help!

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  • Haskell Linear Algebra Matrix Library for Arbitrary Element Types

    - by Johannes Weiß
    I'm looking for a Haskell linear algebra library that has the following features: Matrix multiplication Matrix addition Matrix transposition Rank calculation Matrix inversion is a plus and has the following properties: arbitrary element (scalar) types (in particular element types that are not Storable instances). My elements are an instance of Num, additionally the multiplicative inverse can be calculated. The elements mathematically form a finite field (??2256). That should be enough to implement the features mentioned above. arbitrary matrix sizes (I'll probably need something like 100x100, but the matrix sizes will depend on the user's input so it should not be limited by anything else but the memory or the computational power available) as fast as possible, but I'm aware that a library for arbitrary elements will probably not perform like a C/Fortran library that does the work (interfaced via FFI) because of the indirection of arbitrary (non Int, Double or similar) types. At least one pointer gets dereferenced when an element is touched (written in Haskell, this is not a real requirement for me, but since my elements are no Storable instances the library has to be written in Haskell) I already tried very hard and evaluated everything that looked promising (most of the libraries on Hackage directly state that they wont work for me). In particular I wrote test code using: hmatrix, assumes Storable elements Vec, but the documentation states: Low Dimension : Although the dimensionality is limited only by what GHC will handle, the library is meant for 2,3 and 4 dimensions. For general linear algebra, check out the excellent hmatrix library and blas bindings I looked into the code and the documentation of many more libraries but nothing seems to suit my needs :-(. Update Since there seems to be nothing, I started a project on GitHub which aims to develop such a library. The current state is very minimalistic, not optimized for speed at all and only the most basic functions have tests and therefore should work. But should you be interested in using or helping out developing it: Contact me (you'll find my mail address on my web site) or send pull requests.

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