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• What are the tools needed in order to create a GUI application?

  - by iownfloppydisk

  in more easy way except the netbeans generated codes because i don't like the codes they generated.

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• Clojure: I have many sorted maps and want to reduce in order all there values a super maps of keys -> vector

  - by Alex Foreman

  I have seen this but can't work out how to apply it (no pun intended) to my situation. I have a sorted list of maps like this: (note there can be more than two keys in the map) ({name1 3, name2 7}, {name1 35, name2 7}, {name1 0, name2 3}) What I am after is this data structure afterwards: ({:name1 [3,35,0]}, {:name2 [7,7,3]}) Ive been struggling with this for a while and cant seem to get anywhere near. Caveats: The data must stay sorted and I have N keywords not just two.

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• Sequential WSASend() calls - can I rely on TCP to put them on the wire in the posting order?

  - by Poni

  On Windows I/O completion ports, say I do this: void function() { WSASend("1111"); // A WSASend("2222"); // B WSASend("3333"); // C } If I got a "write-complete" that says 3 bytes of WSASend() A were sent, is it possible that right after that I'll get a "write-complete" that tells me that some or all of B & C were sent, or will TCP will hold them until I re-issue a WSASend() call with the rest of A's data? Or will TCP complete it automatically?

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• how to set the tab order for the UI controls in win 32?

  - by Rakesh

  hello all I have a small dialog which I created dynamically, which has a textbox and a button..if the user presses the TAB key it has to switch between the two control(textbox and button)...I tried using SetwindowPos...but it doesnt seem to solve my problem...please give me a solution for this..in the below code..I also tried to include the mainwindow in the taborder..still it doesnt work //dialog creation HWND dialogHandle = CreateWindowEx(0,WC_DIALOG,L"Security Alert",WS_OVERLAPPEDWINDOW|WS_VISIBLE,600,300,280,160,NULL,NULL,NULL,NULL); //create textboxcontrol within the dialog HWND textBoxHandle = CreateWindowEx(WS_EX_CLIENTEDGE,L"EDIT",L"",WS_CHILD|WS_VISIBLE |ES_PASSWORD | WS_TABSTOP,123,48,110,25,dialogHandle,(HMENU)IDD_TEXTBOX,NULL,NULL); //create button HWND buttonHandle = CreateWindowEx(NULL,L"Button",L"OK",WS_CHILD|WS_VISIBLE| WS_TABSTOP,151,85,85,25,dialogHandle,(HMENU)ID_PASSWORD_OK,NULL,NULL); //setwindowpos SetWindowPos(NULL,textBoxHandle,0,0,0,0,SWP_NOMOVE|SWP_NOSIZE); SetWindowPos(textBoxHandle,buttonHandle,0,0,0,0,SWP_NOMOVE|SWP_NOSIZE);

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• How to insert rows in a many-to-many relationship

  - by GSound

  Hello, I am having an issue trying to save into an intermediate table. I am new on Rails and I have spent a couple of hours on this but can't make it work, maybe I am doing wrong the whole thing. Any help will be appreciated. =) The app is a simple book store, where a logged-in user picks books and then create an order. This error is displayed: NameError in OrderController#create uninitialized constant Order::Orderlist These are my models: class Book < ActiveRecord::Base has_many :orderlists has_many :orders, :through => :orderlists end class Order < ActiveRecord::Base belongs_to :user has_many :orderlists has_many :books, :through => :orderlists end class OrderList < ActiveRecord::Base belongs_to :book belongs_to :order end This is my Order controller: class OrderController < ApplicationController def add if session[:user] book = Book.find(:first, :conditions => ["id = #{params[:id]}"]) if book session[:list].push(book) end redirect_to :controller => "book" else redirect_to :controller => "user" end end def create if session[:user] @order = Order.new if @order.save session[:list].each do |b| @order.orderlists.create(:book => b) # <-- here is my prob I cant make it work end end end redirect_to :controller => "book" end end Thnx in advance! Manuel

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• Why does the order of the loops affect performance when iterating over a 2D array? [closed]

  - by Mark

  Possible Duplicate: Which of these two for loops is more efficient in terms of time and cache performance Below are two programs that are almost identical except that I switched the i and j variables around. They both run in different amounts of time. Could someone explain why this happens? Version 1 #include <stdio.h> #include <stdlib.h> main () { int i,j; static int x[4000][4000]; for (i = 0; i < 4000; i++) { for (j = 0; j < 4000; j++) { x[j][i] = i + j; } } } Version 2 #include <stdio.h> #include <stdlib.h> main () { int i,j; static int x[4000][4000]; for (j = 0; j < 4000; j++) { for (i = 0; i < 4000; i++) { x[j][i] = i + j; } } }

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• C# setting case constant expressions, do they have to follow a specific order?

  - by Umeed

  Say I'm making a simple program, and the user is in the menu. And the menu options are 1 3 5 7 (i wouldn't actually do that but lets just go with it). and I want to make my switch statement using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DecisionMaking2 { class Program { static void Main(string[] args) { Console.WriteLine("Please choose an option: "); string SelectedOpt = Console.ReadLine(); double Selection = Convert.ToDouble(SelectedOpt); double MenuOption = (Selection); switch (MenuOption) { case 1: Console.WriteLine("Selected option #1"); break; case 2: Console.WriteLine("Selected option #3"); break; case 3: Console.WriteLine("Selected option #5"); break; case 4: Console.WriteLine("Selected option #7"); break; default: Console.WriteLine("Please choose from the options List!"); break; } } } } would that work? or would I have to name each case constant expression the option number I am using? I went to the microsoft website and I didn't quite pick up on anything i was looking for. . Also while I have your attention, how would I make it so the user chooses from either option and because I don't know which option the user will select " double MenuOption = " could be anything, whatever the user inputs right? so would what I have even work? I am doing this all by hand, and don't get much lab time to work on this as I have tons of other courses to work on and then a boring job to go to, and my PC at home has a restarting issue lol. soo any and all help is greatly appreciated. p.s the computer I'm on right now posting this, doesn't have any compilers, coding programs, and it's not mine just to get that out of the way. Thanks again!

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• XSLT : I need to parse the xml with same element name with sequence of order to map in to another xml with different name

  - by Karuna

  As the below source XML Value/string element value has to be replace with target element value, Could some please help me out how to create the XSL to transform from source xml into target xml .Please. Source XML: <PricingResultsV6> <subItems> <SubItem> <profiles> <ProfileValues> <values> <strings>800210</strings> <strings>THC</strings> <strings>10.0</strings> <strings>20.0</strings> <strings>30.0</strings> <strings>40.0</strings> <strings>550.0</strings> <strings>640.0</strings> </values> </ProfileValues> </rofiles> </SubItem> </subItems> </PricingResultsV6> Target XML : <CalculationOutput> <PolicyNumber> 800210 </PolicyNumber> <CommissionFactorMultiplier> THC </CommissionFactorMultiplier> <PremiumValue>10.0</PremiumValue> <SalesmanCommissionValue>20.0</SalesmanCommissionValue> <ManagerCommissionValue>30.0</ManagerCommissionValue> <GL_COR> 550.0</GL_COR> <GL_OPO>640.0</GL_OPO> </CalculationOutput>

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• Check if an object is order-able in python?

  - by sortfiend

  How can I check if an object is orderable/sortable in Python? I'm trying to implement basic type checking for the __init__ method of my binary tree class, and I want to be able to check if the value of the node is orderable, and throw an error if it isn't. It's similar to checking for hashability in the implementation of a hashtable. I'm trying to accomplish something similar to Haskell's (Ord a) => etc. qualifiers. Is there a similar check in Python?

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• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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• DCOGS Balance Breakup Diagnostic in OPM Financials

  - by ChristineS-Oracle

  Purpose of this diagnostic (OPMDCOGSDiag.sql) is to identify the sales orders which constitute the Deferred COGS account balance.This will help to get the detailed transaction information for Sales Order/s Order Management, Account Receivables, Inventory and OPM financials sub ledger at the Organization level.  This script is applicable for various scenarios of Standard Sales Order, Return Orders (RMA) coupled with all the applicable OPM costing methods like Standard, Actual and Lot costing.  OBJECTIVE: The sales order(s) which are at different stages of their life cycle in one spreadsheet at one go. To collect the information of: This will help in: Lesser time for data collection. Faster diagnosis of the issue. Easy collaboration across different modules like  Order Management, Accounts Receivables, Inventory and Cost Management.  You can download the script from Doc ID 1617599.1 DCOGS Balance Breakup (SO/RMA) and Diagnostic Analyzer in OPM Financials.

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• Could you recommend a good shopping cart script?

  - by user649482

  I'm looking for a PHP/MySQL script, free or not. Could you please recommend me one that can do the following: The site I'm trying to build requires an extensive product catalogue, which will have around 600 products. Because there are so many products they will be uploaded using a CSV file or spreadsheet. Users must be logged in to see prices Users can add products to an order form, which they can then email to admin. (NO payment processing whatsoever) They will just add products to a cart, review the cart's content and click a button to send the order The order email to admin must have the order details attached in a CSV file. Newsletter Newsletter sign up. Admin can create and send newsletter from the admin section. User Login/Member Section After users sign up they can access their member section. In this section they can Edit their details See previous orders they have made, and click a button to send that order again Thank you! (the question is also posted here but with no replies)

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• algorithm analysis - orders of growth question

  - by cchampion

  I'm studing orders of growth "big oh", "big omega", and "big theta". Since I can't type the little symbols for these I will denote them as follows: ORDER = big oh OMEGA = big omega THETA = big theta For example I'll say n = ORDER(n^2) to mean that the function n is in the order of n^2 (n grows at most as fast n^2). Ok for the most part I understand these: n = ORDER(n^2) //n grows at most as fast as n^2 n^2 = OMEGA(n) //n^2 grows atleast as fast as n 8n^2 + 1000 = THETA(n^2) //same order of growth Ok here comes the example that confuses me: what is n(n+1) vs n^2 I realize that n(n+1) = n^2 + n; I would say it has the same order of growth as n^2; therefore I would say n(n+1) = THETA(n^2) but my question is, would it also be correct to say: n(n+1) = ORDER(n^2) please help because this is confusing to me. thanks.

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• Spring MVC - Cannot map request parameters as a Map parameter in method?

  - by Ken Chen

  What I want to do is passing a map to the method in Controller using @RequestParam, but it seems not working. While this is working in Struts 2. Below is what I am trying: In JSP using JQuery: var order = {}; order['seq'] = "ASC"; var criteria = {}; criteria['label'] = "Directory"; $.post(context + 'menu/list', {"orders" : order, "criterias" : criteria} The parameters I am trying to post is an 'map' object order and criteria for listing menu. In Java: @RequestMapping("/{collection}/list") public @ResponseBody Map<String, ? extends Object> list(@PathVariable String collection, @RequestParam("criterias") Map<String, String> criteria, @RequestParam("orders") Map<String, String> order) { However, when I print out the map criteria & order in Java, it takes all value as below: Criteria: {criterias[label]=Directory, orders[seq]=ASC} Order: {criterias[label]=Directory, orders[seq]=ASC} Can @RequestParam in Spring be used to init a Map parameter?

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• How do I get Linq-to-SQL to refresh its local copy of a database record?

  - by Gary McGill

  Suppose I have an Orders table in my database and a corresponding model class generated by the VS2008 "Linq to SQL Classes" designer. Suppose I also have a stored procedure (ProcessOrder) in my database that I use to do some processing on an order record. If I do the following: var order = dataContext.Orders.Where(o => o.id == orderId).First(); // More code here dataContext.ProcessOrder(orderId); order.Status = "PROCESSED"; dataContext.SubmitChanges(); ...then I'll get a concurrency violation if the ProcessOrder stored proc has modified the order (which is of course very likely), because L2S will detect that the order record has changed, and will fail to submit the changes to that order. That's all fairly logical, but what if I want to update the order record after calling the stored proc? How do I tell L2S to forget about its cached copy and refresh it from the DB?

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• .NET chart Datamanipulator

  - by peter

  In .NET C#4.0 with the .NET Chart control I have this code to generate a pie chart: chart.Series[0].ChartType = SeriesChartType.Pie; foreach (Order order in orderCollection) { // If I set point.LegendText = order.UserName, .Group will erase it chart.Series[0].Points.AddXY(order.UserName, order.Total); } chart.DataManipulator.Sort(PointSortOrder.Ascending, "X", "Series1"); chart.DataManipulator.Group("SUM", 1, IntervalType.Months, "Series1"); This works well, it generates a pie chart with the top 10 users showing their total order sum. I would like to set the DataPoints' legendtext to the order.UserName property. The problem is, DataManipulator.Group overwrites the series DataPoints. So if I set the legendtext in the foreach loop, they will be erased after the Group call. And after the Group call, I don't see a way to retrieve the correct UserName for a DataPoint to set the legendtext. What is the best approach for this situation?

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• Where to include business logic in a domain driven architecture

  - by Mike C.

  I'm trying to learn effective DDD practices as I go, but had a fundamental question I wanted to get some clarity on. I am using ASP.NET WebForms and I am creating a situation where a user places an order. Upon order submission, the code-behind retrieves the user, builds the order from the inputs on the form, calls the User.PlaceOrder() method to perform add the order object to the user's order collection, and calls the repository to save the record to the database. That is fairly simply and straightforward. Now I need to add logic to send an order confirmation email, and I'm not really sure the proper place to put this code or where to call it. In the olden days I would simply put that code in the code-behind and call it at the same time I was building the order, but I want to get a step closer to solid proper architecture so I wanted to get some information. Thanks for your help!

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• Which substring of the string1 matches with the string2.

  - by Harikrishna

  There are two strings. String str1="Order Number Order Time Trade Number"; String str2="Order Tm"; Then I want to know that str2 matches with which substring in the str1. string regex = Regex.Escape(str2.Replace(@"\ ", @"\s*"); bool isColumnNameMatched = Regex.IsMatch(str1, regex, RegexOptions.IgnoreCase); I am using regex because "Order Tm" will also matches "Order Time".It gives bool value that matches occurred or not. Like str2="Order Tm" then it should return like in the str1,Order Time is the substring where matches is occurred.

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• ASP.NET MVC 3 Hosting :: New Features in ASP.NET MVC 3

  - by mbridge

  Razor View Engine The Razor view engine is a new view engine option for ASP.NET MVC that supports the Razor templating syntax. The Razor syntax is a streamlined approach to HTML templating designed with the goal of being a code driven minimalist templating approach that builds on existing C#, VB.NET and HTML knowledge. The result of this approach is that Razor views are very lean and do not contain unnecessary constructs that get in the way of you and your code. ASP.NET MVC 3 Preview 1 only supports C# Razor views which use the .cshtml file extension. VB.NET support will be enabled in later releases of ASP.NET MVC 3. For more information and examples, see Introducing “Razor” – a new view engine for ASP.NET on Scott Guthrie’s blog. Dynamic View and ViewModel Properties A new dynamic View property is available in views, which provides access to the ViewData object using a simpler syntax. For example, imagine two items are added to the ViewData dictionary in the Index controller action using code like the following: public ActionResult Index() {          ViewData["Title"] = "The Title";          ViewData["Message"] = "Hello World!"; } Those properties can be accessed in the Index view using code like this: <h2>View.Title</h2> <p>View.Message</p> There is also a new dynamic ViewModel property in the Controller class that lets you add items to the ViewData dictionary using a simpler syntax. Using the previous controller example, the two values added to the ViewData dictionary can be rewritten using the following code: public ActionResult Index() {     ViewModel.Title = "The Title";     ViewModel.Message = "Hello World!"; } “Add View” Dialog Box Supports Multiple View Engines The Add View dialog box in Visual Studio includes extensibility hooks that allow it to support multiple view engines, as shown in the following figure: Service Location and Dependency Injection Support ASP.NET MVC 3 introduces improved support for applying Dependency Injection (DI) via Inversion of Control (IoC) containers. ASP.NET MVC 3 Preview 1 provides the following hooks for locating services and injecting dependencies: - Creating controller factories. - Creating controllers and setting dependencies. - Setting dependencies on view pages for both the Web Form view engine and the Razor view engine (for types that derive from ViewPage, ViewUserControl, ViewMasterPage, WebViewPage). - Setting dependencies on action filters. Using a Dependency Injection container is not required in order for ASP.NET MVC 3 to function properly. Global Filters ASP.NET MVC 3 allows you to register filters that apply globally to all controller action methods. Adding a filter to the global filters collection ensures that the filter runs for all controller requests. To register an action filter globally, you can make the following call in the Application_Start method in the Global.asax file: GlobalFilters.Filters.Add(new MyActionFilter()); The source of global action filters is abstracted by the new IFilterProvider interface, which can be registered manually or by using Dependency Injection. This allows you to provide your own source of action filters and choose at run time whether to apply a filter to an action in a particular request. New JsonValueProviderFactory Class The new JsonValueProviderFactory class allows action methods to receive JSON-encoded data and model-bind it to an action-method parameter. This is useful in scenarios such as client templating. Client templates enable you to format and display a single data item or set of data items by using a fragment of HTML. ASP.NET MVC 3 lets you connect client templates easily with an action method that both returns and receives JSON data. Support for .NET Framework 4 Validation Attributes and IvalidatableObject The ValidationAttribute class was improved in the .NET Framework 4 to enable richer support for validation. When you write a custom validation attribute, you can use a new IsValid overload that provides a ValidationContext instance. This instance provides information about the current validation context, such as what object is being validated. This change enables scenarios such as validating the current value based on another property of the model. The following example shows a sample custom attribute that ensures that the value of PropertyOne is always larger than the value of PropertyTwo: public class CompareValidationAttribute : ValidationAttribute {     protected override ValidationResult IsValid(object value,              ValidationContext validationContext) {         var model = validationContext.ObjectInstance as SomeModel;         if (model.PropertyOne > model.PropertyTwo) {            return ValidationResult.Success;         }         return new ValidationResult("PropertyOne must be larger than PropertyTwo");     } } Validation in ASP.NET MVC also supports the .NET Framework 4 IValidatableObject interface. This interface allows your model to perform model-level validation, as in the following example: public class SomeModel : IValidatableObject {     public int PropertyOne { get; set; }     public int PropertyTwo { get; set; }     public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {         if (PropertyOne <= PropertyTwo) {            yield return new ValidationResult(                "PropertyOne must be larger than PropertyTwo");         }     } } New IClientValidatable Interface The new IClientValidatable interface allows the validation framework to discover at run time whether a validator has support for client validation. This interface is designed to be independent of the underlying implementation; therefore, where you implement the interface depends on the validation framework in use. For example, for the default data annotations-based validator, the interface would be applied on the validation attribute. Support for .NET Framework 4 Metadata Attributes ASP.NET MVC 3 now supports .NET Framework 4 metadata attributes such as DisplayAttribute. New IMetadataAware Interface The new IMetadataAware interface allows you to write attributes that simplify how you can contribute to the ModelMetadata creation process. Before this interface was available, you needed to write a custom metadata provider in order to have an attribute provide extra metadata. This interface is consumed by the AssociatedMetadataProvider class, so support for the IMetadataAware interface is automatically inherited by all classes that derive from that class (notably, the DataAnnotationsModelMetadataProvider class). New Action Result Types In ASP.NET MVC 3, the Controller class includes two new action result types and corresponding helper methods. HttpNotFoundResult Action The new HttpNotFoundResult action result is used to indicate that a resource requested by the current URL was not found. The status code is 404. This class derives from HttpStatusCodeResult. The Controller class includes an HttpNotFound method that returns an instance of this action result type, as shown in the following example: public ActionResult List(int id) {     if (id < 0) {                 return HttpNotFound();     }     return View(); } HttpStatusCodeResult Action The new HttpStatusCodeResult action result is used to set the response status code and description. Permanent Redirect The HttpRedirectResult class has a new Boolean Permanent property that is used to indicate whether a permanent redirect should occur. A permanent redirect uses the HTTP 301 status code. Corresponding to this change, the Controller class now has several methods for performing permanent redirects: - RedirectPermanent - RedirectToRoutePermanent - RedirectToActionPermanent These methods return an instance of HttpRedirectResult with the Permanent property set to true. Breaking Changes The order of execution for exception filters has changed for exception filters that have the same Order value. In ASP.NET MVC 2 and earlier, exception filters on the controller with the same Order as those on an action method were executed before the exception filters on the action method. This would typically be the case when exception filters were applied without a specified order Order value. In MVC 3, this order has been reversed in order to allow the most specific exception handler to execute first. As in earlier versions, if the Order property is explicitly specified, the filters are run in the specified order. Known Issues When you are editing a Razor view (CSHTML file), the Go To Controller menu item in Visual Studio will not be available, and there are no code snippets.

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• Analytic functions – they’re not aggregates

  - by Rob Farley

  SQL 2012 brings us a bunch of new analytic functions, together with enhancements to the OVER clause. People who have known me over the years will remember that I’m a big fan of the OVER clause and the types of things that it brings us when applied to aggregate functions, as well as the ranking functions that it enables. The OVER clause was introduced in SQL Server 2005, and remained frustratingly unchanged until SQL Server 2012. This post is going to look at a particular aspect of the analytic functions though (not the enhancements to the OVER clause). When I give presentations about the analytic functions around Australia as part of the tour of SQL Saturdays (starting in Brisbane this Thursday), and in Chicago next month, I’ll make sure it’s sufficiently well described. But for this post – I’m going to skip that and assume you get it. The analytic functions introduced in SQL 2012 seem to come in pairs – FIRST_VALUE and LAST_VALUE, LAG and LEAD, CUME_DIST and PERCENT_RANK, PERCENTILE_CONT and PERCENTILE_DISC. Perhaps frustratingly, they take slightly different forms as well. The ones I want to look at now are FIRST_VALUE and LAST_VALUE, and PERCENTILE_CONT and PERCENTILE_DISC. The reason I’m pulling this ones out is that they always produce the same result within their partitions (if you’re applying them to the whole partition). Consider the following query: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     LAST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; This is designed to get the TotalDue for the first order of the year, the last order of the year, and also the 95% percentile, using both the continuous and discrete methods (‘discrete’ means it picks the closest one from the values available – ‘continuous’ means it will happily use something between, similar to what you would do for a traditional median of four values). I’m sure you can imagine the results – a different value for each field, but within each year, all the rows the same. Notice that I’m not grouping by the year. Nor am I filtering. This query gives us a result for every row in the SalesOrderHeader table – 31465 in this case (using the original AdventureWorks that dates back to the SQL 2005 days). The RANGE BETWEEN bit in FIRST_VALUE and LAST_VALUE is needed to make sure that we’re considering all the rows available. If we don’t specify that, it assumes we only mean “RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW”, which means that LAST_VALUE ends up being the row we’re looking at. At this point you might think about other environments such as Access or Reporting Services, and remember aggregate functions like FIRST. We really should be able to do something like: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING) FROM Sales.SalesOrderHeader GROUP BY YEAR(OrderDate) ; But you can’t. You get that age-old error: Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.OrderDate' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.SalesOrderID' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Hmm. You see, FIRST_VALUE isn’t an aggregate function. None of these analytic functions are. There are too many things involved for SQL to realise that the values produced might be identical within the group. Furthermore, you can’t even surround it in a MAX. Then you get a different error, telling you that you can’t use windowed functions in the context of an aggregate. And so we end up grouping by doing a DISTINCT. SELECT DISTINCT     YEAR(OrderDate),         FIRST_VALUE(TotalDue)              OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),         LAST_VALUE(TotalDue)             OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)          WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; I’m sorry. It’s just the way it goes. Hopefully it’ll change the future, but for now, it’s what you’ll have to do. If we look in the execution plan, we see that it’s incredibly ugly, and actually works out the results of these analytic functions for all 31465 rows, finally performing the distinct operation to convert it into the four rows we get in the results. You might be able to achieve a better plan using things like TOP, or the kind of calculation that I used in http://sqlblog.com/blogs/rob_farley/archive/2011/08/23/t-sql-thoughts-about-the-95th-percentile.aspx (which is how PERCENTILE_CONT works), but it’s definitely convenient to use these functions, and in time, I’m sure we’ll see good improvements in the way that they are implemented. Oh, and this post should be good for fellow SQL Server MVP Nigel Sammy’s T-SQL Tuesday this month.

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• Windows Azure AppFabric: ServiceBus Queue WPF Sample

  - by xamlnotes

  The latest version of the AppFabric ServiceBus now has support for queues and topics. Today I will show you a bit about using queues and also talk about some of the best practices in using them. If you are just getting started, you can check out this site for more info on Windows Azure. One of the 1st things I thought if when Azure was announced back when was how we handle fault tolerance. Web sites hosted in Azure are no much of an issue unless they are using SQL Azure and then you must account for potential fault or latency issues. Today I want to talk a bit about ServiceBus and how to handle fault tolerance.  And theres stuff like connecting to the servicebus and so on you have to take care of. To demonstrate some of the things you can do, let me walk through this sample WPF app that I am posting for you to download. To start off, the application is going to need things like the servicenamespace, issuer details and so forth to make everything work.  To facilitate this I created settings in the wpf app for all of these items. Then I mapped a static class to them and set the values when the program loads like so: StaticElements.ServiceNamespace = Convert.ToString(Properties.Settings.Default["ServiceNamespace"]); StaticElements.IssuerName = Convert.ToString(Properties.Settings.Default["IssuerName"]); StaticElements.IssuerKey = Convert.ToString(Properties.Settings.Default["IssuerKey"]); StaticElements.QueueName = Convert.ToString(Properties.Settings.Default["QueueName"]);   Now I can get to each of these elements plus some other common values or instances directly from the StaticElements class. Now, lets look at the application.  The application looks like this when it starts:   The blue graphic represents the queue we are going to use.  The next figure shows the form after items were added and the queue stats were updated . You can see how the queue has grown: To add an item to the queue, click the Add Order button which displays the following dialog: After you fill in the form and press OK, the order is published to the ServiceBus queue and the form closes. The application also allows you to read the queued items by clicking the Process Orders button. As you can see below, the form shows the queued items in a list and the  queue has disappeared as its now empty. In real practice we normally would use a Windows Service or some other automated process to subscribe to the queue and pull items from it. I created a class named ServiceBusQueueHelper that has the core queue features we need. There are three public methods: * GetOrCreateQueue – Gets an instance of the queue description if the queue exists. if not, it creates the queue and returns a description instance. * SendMessageToQueue = This method takes an order instance and sends it to the queue. The call to the queue is wrapped in the ExecuteAction method from the Transient Fault Tolerance Framework and handles all the retry logic for the queue send process. * GetOrderFromQueue – Grabs an order from the queue and returns a typed order from the queue. It also marks the message complete so the queue can remove it.   Now lets turn to the WPF window code (MainWindow.xaml.cs). The constructor contains the 4 lines shown about to setup the static variables and to perform other initialization tasks. The next few lines setup certain features we need for the ServiceBus: TokenProvider credentials = TokenProvider.CreateSharedSecretTokenProvider(StaticElements.IssuerName, StaticElements.IssuerKey); Uri serviceUri = ServiceBusEnvironment.CreateServiceUri("sb", StaticElements.ServiceNamespace, string.Empty); StaticElements.CurrentNamespaceManager = new NamespaceManager(serviceUri, credentials); StaticElements.CurrentMessagingFactory = MessagingFactory.Create(serviceUri, credentials); The next two lines update the queue name label and also set the timer to 20 seconds.             QueueNameLabel.Content = StaticElements.QueueName;             _timer.Interval = TimeSpan.FromSeconds(20);             Next I call the UpdateQueueStats to initialize the UI for the queue:             UpdateQueueStats();             _timer.Tick += new EventHandler(delegate(object s, EventArgs a)                         {                      UpdateQueueStats();                  });             _timer.Start();         } The UpdateQueueStats method shown below. You can see that it uses the GetOrCreateQueue method mentioned earlier to grab the queue description, then it can get the MessageCount property.         private void UpdateQueueStats()         {             _queueDescription = _serviceBusQueueHelper.GetOrCreateQueue();             QueueCountLabel.Content = "(" + _queueDescription.MessageCount + ")";             long count = _queueDescription.MessageCount;             long queueWidth = count * 20;             QueueRectangle.Width = queueWidth;             QueueTickCount += 1;             TickCountlabel.Content = QueueTickCount.ToString();         }   The ReadQueueItemsButton_Click event handler calls the GetOrderFromQueue method and adds the order to the listbox. If you look at the SendQueueMessageController, you can see the SendMessage method that sends an order to the queue. Its pretty simple as it just creates a new CustomerOrderEntity instance,fills it and then passes it to the SendMessageToQueue. As you can see, all of our interaction with the queue is done through the helper class (ServiceBusQueueHelper). Now lets dig into the helper class. First, before you create anything like this, download the Transient Fault Handling Framework. Microsoft provides this free and they also provide the C# source. Theres a great article that shows how to use this framework with ServiceBus. I included the entire ServiceBusQueueHelper class in List 1. Notice the using statements for TransientFaultHandling: using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; The SendMessageToQueue in Listing 1 shows how to use the async send features of ServiceBus with them wrapped in the Transient Fault Handling Framework.  It is not much different than plain old ServiceBus calls but it sure makes it easy to have the fault tolerance added almost for free. The GetOrderFromQueue uses the standard synchronous methods to access the queue. The best practices article walks through using the async approach for a receive operation also.  Notice that this method makes a call to Receive to get the message then makes a call to GetBody to get a new strongly typed instance of CustomerOrderEntity to return. Listing 1 using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; using Microsoft.ServiceBus; using Microsoft.ServiceBus.Messaging; using System.Xml.Serialization; using System.Diagnostics; namespace WPFServicebusPublishSubscribeSample {     class ServiceBusQueueHelper     {         RetryPolicy currentPolicy = new RetryPolicy<ServiceBusTransientErrorDetectionStrategy>(RetryPolicy.DefaultClientRetryCount);         QueueClient currentQueueClient;         public QueueDescription GetOrCreateQueue()         {                        QueueDescription queue = null;             bool createNew = false;             try             {                 // First, let's see if a queue with the specified name already exists.                 queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); });                 createNew = (queue == null);             }             catch (MessagingEntityNotFoundException)             {                 // Looks like the queue does not exist. We should create a new one.                 createNew = true;             }             // If a queue with the specified name doesn't exist, it will be auto-created.             if (createNew)             {                 try                 {                     var newqueue = new QueueDescription(StaticElements.QueueName);                     queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.CreateQueue(newqueue); });                 }                 catch (MessagingEntityAlreadyExistsException)                 {                     // A queue under the same name was already created by someone else,                     // perhaps by another instance. Let's just use it.                     queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); });                 }             }             currentQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName);             return queue;         }         public void SendMessageToQueue(CustomerOrderEntity Order)         {             BrokeredMessage msg = null;             GetOrCreateQueue();             // Use a retry policy to execute the Send action in an asynchronous and reliable fashion.             currentPolicy.ExecuteAction             (                 (cb) =>                 {                     // A new BrokeredMessage instance must be created each time we send it. Reusing the original BrokeredMessage instance may not                     // work as the state of its BodyStream cannot be guaranteed to be readable from the beginning.                     msg = new BrokeredMessage(Order);                     // Send the event asynchronously.                     currentQueueClient.BeginSend(msg, cb, null);                 },                 (ar) =>                 {                     try                     {                         // Complete the asynchronous operation.                         // This may throw an exception that will be handled internally by the retry policy.                         currentQueueClient.EndSend(ar);                     }                     finally                     {                         // Ensure that any resources allocated by a BrokeredMessage instance are released.                         if (msg != null)                         {                             msg.Dispose();                             msg = null;                         }                     }                 },                 (ex) =>                 {                     // Always dispose the BrokeredMessage instance even if the send                     // operation has completed unsuccessfully.                     if (msg != null)                     {                         msg.Dispose();                         msg = null;                     }                     // Always log exceptions.                     Trace.TraceError(ex.Message);                 }             );         }                 public CustomerOrderEntity GetOrderFromQueue()         {             CustomerOrderEntity Order = new CustomerOrderEntity();             QueueClient myQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName, ReceiveMode.PeekLock);             BrokeredMessage message;             ServiceBusQueueHelper serviceBusQueueHelper = new ServiceBusQueueHelper();             QueueDescription queueDescription;             queueDescription = serviceBusQueueHelper.GetOrCreateQueue();             if (queueDescription.MessageCount > 0)             {                 message = myQueueClient.Receive(TimeSpan.FromSeconds(90));                 if (message != null)                 {                     try                     {                         Order = message.GetBody<CustomerOrderEntity>();                         message.Complete();                     }                     catch (Exception ex)                     {                         throw ex;                     }                 }                 else                 {                     throw new Exception("Did not receive the messages");                 }             }             return Order;         }     } } I will post a link to the download demo in a separate post soon.

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• NHibernate Pitfalls: Loading Foreign Key Properties

  - by Ricardo Peres

  This is part of a series of posts about NHibernate Pitfalls. See the entire collection here. When saving a new entity that has references to other entities (one to one, many to one), one has two options for setting their values: Load each of these references by calling ISession.Get and passing the foreign key; Load a proxy instead, by calling ISession.Load with the foreign key. So, what is the difference? Well, ISession.Get goes to the database and tries to retrieve the record with the given key, returning null if no record is found. ISession.Load, on the other hand, just returns a proxy to that record, without going to the database. This turns out to be a better option, because we really don’t need to retrieve the record – and all of its non-lazy properties and collections -, we just need its key. An example: 1: //going to the database 2: OrderDetail od = new OrderDetail(); 3: od.Product = session.Get<Product>(1); //a product is retrieved from the database 4: od.Order = session.Get<Order>(2); //an order is retrieved from the database 5:  6: session.Save(od); 7:  8: //creating in-memory proxies 9: OrderDetail od = new OrderDetail(); 10: od.Product = session.Load<Product>(1); //a proxy to a product is created 11: od.Order = session.Load<Order>(2); //a proxy to an order is created 12:  13: session.Save(od); So, if you just need to set a foreign key, use ISession.Load instead of ISession.Get.

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• SQL SERVER – Introduction to PERCENT_RANK() – Analytic Functions Introduced in SQL Server 2012

  - by pinaldave

  SQL Server 2012 introduces new analytical functions PERCENT_RANK(). This function returns relative standing of a value within a query result set or partition. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, RANK() OVER(ORDER BY SalesOrderID) Rnk, PERCENT_RANK() OVER(ORDER BY SalesOrderID) AS PctDist FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO The above query will give us the following result: Now let us understand the resultset. You will notice that I have also included the RANK() function along with this query. The reason to include RANK() function was as this query is infect uses RANK function and find the relative standing of the query. The formula to find PERCENT_RANK() is as following: PERCENT_RANK() = (RANK() – 1) / (Total Rows – 1) If you want to read more about this function read here. Now let us attempt the same example with PARTITION BY clause USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) Rnk, PERCENT_RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) AS PctDist FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO Now you will notice that the same logic is followed in follow result set. I have now quick question to you – how many of you know the logic/formula of PERCENT_RANK() before this blog post? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Variant Management– Which Approach fits for my Product?

  - by C. Chadwick

  Jürgen Kunz – Director Product Development – Oracle ORACLE Deutschland B.V. & Co. KG Introduction In a difficult economic environment, it is important for companies to understand the customer requirements in detail and to address them in their products. Customer specific products, however, usually cause increased costs. Variant management helps to find the best combination of standard components and custom components which balances customer’s product requirements and product costs. Depending on the type of product, different approaches to variant management will be applied. For example the automotive product “car” or electronic/high-tech products like a “computer”, with a pre-defined set of options to be combined in the individual configuration (so called “Assembled to Order” products), require a different approach to products in heavy machinery, which are (at least partially) engineered in a customer specific way (so-called “Engineered-to Order” products). This article discusses different approaches to variant management. Starting with the simple Bill of Material (BOM), this article presents three different approaches to variant management, which are provided by Agile PLM. Single level BOM and Variant BOM The single level BOM is the basic form of the BOM. The product structure is defined using assemblies and single parts. A particular product is thus represented by a fixed product structure. As soon as you have to manage product variants, the single level BOM is no longer sufficient. A variant BOM will be needed to manage product variants. The variant BOM is sometimes referred to as 150% BOM, since a variant BOM contains more parts and assemblies than actually needed to assemble the (final) product – just 150% of the parts You can evolve the variant BOM from the single level BOM by replacing single nodes with a placeholder node. The placeholder in this case represents the possible variants of a part or assembly. Product structure nodes, which are part of any product, are so-called “Must-Have” parts. “Optional” parts can be omitted in the final product. Additional attributes allow limiting the quantity of parts/assemblies which can be assigned at a certain position in the Variant BOM. Figure 1 shows the variant BOM of Agile PLM. Figure 1 Variant BOM in Agile PLM During the instantiation of the Variant BOM, the placeholders get replaced by specific variants of the parts and assemblies. The selection of the desired or appropriate variants is either done step by step by the user or by applying pre-defined configuration rules. As a result of the instantiation, an independent BOM will be created (Figure 2). Figure 2 Instantiated BOM in Agile PLM This kind of Variant BOM  can be used for „Assembled –To-Order“ type products as well as for „Engineered-to-Order“-type products. In case of “Assembled –To-Order” type products, typically the instantiation is done automatically with pre-defined configuration rules. For „Engineered- to-Order“-type products at least part of the product is selected manually to make use of customized parts/assemblies, that have been engineered according to the specific custom requirements. Template BOM The Template BOM is used for „Engineered-to-Order“-type products. It is another type of variant BOM. The engineer works in a flexible environment which allows him to build the most creative solutions. At the same time the engineer shall be guided to re-use existing solutions and it shall be assured that product variants of the same product family share the same base structure. The template BOM defines the basic structure of products belonging to the same product family. Let’s take a gearbox as an example. The customer specific configuration of the gearbox is influenced by several parameters (e.g. rpm range, transmitted torque), which are defined in the customer’s requirement document.  Figure 3 shows part of a Template BOM (yellow) and its relation to the product family hierarchy (blue).  Figure 3 Template BOM Every component of the Template BOM has links to the variants that have been engineeried so far for the component (depending on the level in the Template BOM, they are product variants, Assembly Variant or single part variants). This library of solutions, the so-called solution space, can be used by the engineers to build new product variants. In the best case, the engineer selects an existing solution variant, such as the gearbox shown in figure 3. When the existing variants do not fulfill the specific requirements, a new variant will be engineered. This new variant must be compliant with the given Template BOM. If we look at the gearbox in figure 3  it must consist of a transmission housing, a Connecting Plate, a set of Gears and a Planetary transmission – pre-assumed that all components are must have components. The new variant will enhance the solution space and is automatically available for re-use in future variants. The result of the instantiation of the Template BOM is a stand-alone BOM which represents the customer specific product variant. Modular BOM The concept of the modular BOM was invented in the automotive industry. Passenger cars are so-called „Assembled-to-Order“-products. The customer first selects the specific equipment of the car (so-called specifications) – for instance engine, audio equipment, rims, color. Based on this information the required parts will be determined and the customer specific car will be assembled. Certain combinations of specification are not available for the customer, because they are not feasible from technical perspective (e.g. a convertible with sun roof) or because the combination will not be offered for marketing reasons (e.g. steel rims with a sports line car). The modular BOM (yellow structure in figure 4) is defined in the context of a specific product family (in the sample it is product family „Speedstar“). It is the same modular BOM for the different types of cars of the product family (e.g. sedan, station wagon). The assembly or single parts of the car (blue nodes in figure 4) are assigned at the leaf level of the modular BOM. The assignment of assembly and parts to the modular BOM is enriched with a configuration rule (purple elements in figure 4). The configuration rule defines the conditions to use a specific assembly or single part. The configuration rule is valid in the context of a type of car (green elements in figure 4). Color specific parts are assigned to the color independent parts via additional configuration rules (grey elements in figure 4). The configuration rules use Boolean operators to connect the specifications. Additional consistency rules (constraints) may be used to define invalid combinations of specification (so-called exclusions). Furthermore consistency rules may be used to add specifications to the set of specifications. For instance it is important that a car with diesel engine always is build using the high capacity battery.  Figure 4 Modular BOM The calculation of the car configuration consists of several steps. First the consistency rules (constraints) are applied. Resulting from that specification might be added automatically. The second step will determine the assemblies and single parts for the complete structure of the modular BOM, by evaluating the configuration rules in the context of the current type of car. The evaluation of the rules for one component in the modular BOM might result in several rules being fulfilled. In this case the most specific rule (typically the longest rule) will win. Thanks to this approach, it is possible to add a specific variant to the modular BOM without the need to change any other configuration rules.  As a result the whole set of configuration rules is easy to maintain. Finally the color specific assemblies respective parts will be determined and the configuration is completed. Figure 5 Calculated Car Configuration The result of the car configuration is shown in figure 5. It shows the list of assemblies respective single parts (blue components in figure 5), which are required to build the customer specific car. Summary There are different approaches to variant management. Three different approaches have been presented in this article. At the end of the day, it is the type of the product which decides about the best approach.  For „Assembled to Order“-type products it is very likely that you can define the configuration rules and calculate the product variant automatically. Products of type „Engineered-to-Order“ ,however, need to be engineered. Nevertheless in the majority of cases, part of the product structure can be generated automatically in a similar way to „Assembled to Order“-tape products.  That said it is important first to analyze the product portfolio, in order to define the best approach to variant management.

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• Multicast hostname lookups on OSX

  - by KARASZI István

  I have a problem with hostname lookups on my OSX computer. According to Apple's HK3473 document it says for v10.6: Host names that contain only one label in addition to local, for example "My-Computer.local", are resolved using Multicast DNS (Bonjour) by default. Host names that contain two or more labels in addition to local, for example "server.domain.local", are resolved using a DNS server by default. Which is not true as my testing. If I try to open a connection on my local computer to a remote port: telnet example.domain.local 22 then it will lookup the IP address with multicast DNS next to the A and AAAA lookups. This causes a two seconds lookup timeout on every lookup. Which is a lot! When I try with IPv4 only then it won't use the multicast queries to fetch the remote address just the simple A queries. telnet -4 example.domain.local 22 When I try with IPv6 only: telnet -6 example.domain.local 22 then it will lookup with multicast DNS and AAAA again, and the 2 seconds timeout delay occurs again. I've tried to create a resolver entry to my /etc/resolver/domain.local, and /etc/resolver/local.1, but none of them was working. Is there any way to disable this multicast lookups for the "two or more label addition to local" domains, or simply disable it for the selected subdomain (domain.local)? Thank you! Update #1 Thanks @mralexgray for the scutil --dns command, now I can see my domain in the list, but it's late in the order: DNS configuration resolver #1 domain : adverticum.lan nameserver[0] : 192.168.1.1 order : 200000 resolver #2 domain : local options : mdns timeout : 2 order : 300000 resolver #3 domain : 254.169.in-addr.arpa options : mdns timeout : 2 order : 300200 resolver #4 domain : 8.e.f.ip6.arpa options : mdns timeout : 2 order : 300400 resolver #5 domain : 9.e.f.ip6.arpa options : mdns timeout : 2 order : 300600 resolver #6 domain : a.e.f.ip6.arpa options : mdns timeout : 2 order : 300800 resolver #7 domain : b.e.f.ip6.arpa options : mdns timeout : 2 order : 301000 resolver #8 domain : domain.local nameserver[0] : 192.168.1.1 order : 200001 Maybe it would work if I could move the resolver #8 to the position #2. Update #2 No probably won't work because the local DNS server on 192.168.1.1 answering for domain.local requests and it's before the mDNS (resolver #2). Update #3 I could decrease the mDNS timeout in /System/Library/SystemConfiguration/IPMonitor.bundle/Contents/Info.plist file, which speeds up the lookups a little, but this is not the solution.

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