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  • Existing LINQ extension method similar to Parallel.For?

    - by Joel Martinez
    The linq extension methods for ienumerable are very handy ... but not that useful if all you want to do is apply some computation to each item in the enumeration without returning anything. So I was wondering if perhaps I was just missing the right method, or if it truly doesn't exist as I'd rather use a built-in version if it's available ... but I haven't found one :-) I could have sworn there was a .ForEach method somewhere, but I have yet to find it. In the meantime, I did write my own version in case it's useful for anyone else: using System.Collections; using System.Collections.Generic; public delegate void Function<T>(T item); public delegate void Function(object item); public static class EnumerableExtensions { public static void For(this IEnumerable enumerable, Function func) { foreach (object item in enumerable) { func(item); } } public static void For<T>(this IEnumerable<T> enumerable, Function<T> func) { foreach (T item in enumerable) { func(item); } } } usage is: myEnumerable.For<MyClass>(delegate(MyClass item) { item.Count++; });

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  • PHP import functions

    - by ninuhadida
    Hi, I'm trying to find the best pragmatic approach to import functions on the fly... let me explain. Say I have a directory called functions which has these files: array_select.func.php stat_mediam.func.php stat_mean.func.php ..... I would like to: load each individual file (which has a function defined inside) and use it just like an internal php function.. such as array_pop(), array_shift(), etc. Once I stumbled on a tutorial (which I can't find again now) that compiled user defined functions as part of a PHP installation.. Although that's not a very good solution because on shared/reseller hosting you can't recompile the PHP installation. I don't want to have conflicts with future versions of PHP / other extensions, i.e. if a function named X by me, is suddenly part of the internal php functions (even though it might not have the same functionality per se) I don't want PHP to throw a fatal error because of this and fail miserably. So the best method that I can think of is to check if a function is defined, using function_exists(), if so throw a notice so that it's easy to track in the log files, otherwise define the function. However that will probably translate to having a lot of include/require statement in other files where I need such a function, which I don't really like. Or possibly, read the directory and loop over each *.func.php file and include_once. Though I find this a bit ugly. The question is, have you ever stumbled upon some source code which handled such a case? How was it implemented? Did you ever do something similar? I need as much ideas as possible! :)

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  • Passing filtering functions to Where() in LINQ-to-SQL

    - by Daniel
    I'm trying to write a set of filtering functions that can be chained together to progressively filter a data set. What's tricky about this is that I want to be able to define the filters in a different context from that in which they'll be used. I've gotten as far as being able to pass a very basic function to the Where() clause in a LINQ statement: filters file: Func<item, bool> returnTrue = (i) => true; repository file: public IQueryable<item> getItems() { return DataContext.Items.Where(returnTrue); } This works. However, as soon as I try to use more complicated logic, the trouble begins: filters file: Func<item, bool> isAssignedToUser = (i) => i.assignedUserId == userId; repository file: public IQueryable<item> getItemsAssignedToUser(int userId) { return DataContext.Items.Where(isAssignedToUser); } This won't even build because userId isn't in the same scope as isAssignedToUser(). I've also tried declaring a function that takes the userId as a parameter: Func<item, int, bool> isAssignedToUser = (i, userId) => i.assignedUserId == userId; The problem with this is that it doesn't fit the function signature that Where() is expecting: Func<item, bool> There must be a way to do this, but I'm at a loss for how. I don't feel like I'm explaining this very well, but hopefully you get the gist. Thanks, Daniel

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  • How to use the LINQ where expression?

    - by NullReference
    I'm implementing the service \ repository pattern in a new project. I've got a base interface that looks like this. Everything works great until I need to use the GetMany method. I'm just not sure how to pass a LINQ expression into the GetMany method. For example how would I simply sort a list of objects of type name? nameRepository.GetMany( ? ) public interface IRepository<T> where T : class { void Add(T entity); void Update(T entity); void Delete(T entity); void Delete(Expression<Func<T, bool>> where); T GetById(long Id); T GetById(string Id); T Get(Expression<Func<T, bool>> where); IEnumerable<T> GetAll(); IEnumerable<T> GetMany(Expression<Func<T, bool>> where); } public virtual IEnumerable<T> GetMany(Expression<Func<T, bool>> where) { return dbset.Where(where).ToList(); }

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  • PHP: passing a function with parameters as parameter

    - by Oden
    Hey, I'm not sure that silly question, but I ask: So, if there is an anonymous function I can give it as another anonymous functions parameter, if it has been already stored a variable. But, whats in that case, if I have stored only one function in a variable, and add the second directly as a parameter into it? Can I add parameters to the non-stored function? Fist example (thats what i understand :) ): $func = function($str){ return $str; }; $func2 = function($str){ return $str; }; $var = $func($func2('asd')); var_dump($var); // prints out string(3) "asd" That makes sense for me, but what is with the following one? $func = function($str){ return $str; }; $var = $func(function($str = "asd"){ return $str; }); var_dump($var); /** This prints out: object(Closure)#1 (1) { ["parameter"]=> array(1) { ["$str"]=> string(10) "" } } But why? */ And at the end, can someone recommend me a book or an article, from what i can learn this lambda coding feature of php? Thank you in advance for your answers :)

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  • How to implement a simple queue properly?

    - by Stephen Hsu
    The current Go library doesn't provide the queue container. To implement a simple queue, I use circle array as the underlying data structure. It follows algorithms mentioned in TAOCP: Insert Y into queue X: X[R]<-Y; R<-(R+1)%M; if R=F then OVERFLOW. Delete Y from queue X: if F=R then UNDERFLOW; Y<-X[F]; F<-(F+1) % M. F: Front, R: Rear, M: Array length. Following is the code: package main import ( "fmt" ) type Queue struct { len int head, tail int q []int } func New(n int) *Queue { return &Queue{n, 0, 0, make([]int, n)} } func (p *Queue) Enqueue(x int) bool { p.q[p.tail] = x p.tail = (p.tail + 1) % p.len return p.head != p.tail } func (p *Queue) Dequeue() (int, bool) { if p.head == p.tail { return 0, false } x := p.q[p.head] p.head = (p.head + 1) % p.len return x, true } func main() { q := New(10) for i := 1; i < 13; i++ { fmt.Println(i, q.Enqueue(i)) } fmt.Println() for i := 1; i < 13; i++ { fmt.Println(q.Dequeue()) } } But the output is obviously wrong: 1 true 2 true 3 true 4 true 5 true 6 true 7 true 8 true 9 true 10 false 11 true 12 true 11 true 12 true 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false 0 false I think I need one more field to make the code work properly. What do you suggest?

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  • Getting unhandled error and connection get lost when a client tries to communicate with chat server in twisted

    - by user2433888
    from twisted.internet.protocol import Protocol,Factory from twisted.internet import reactor class ChatServer(Protocol): def connectionMade(self): print "A Client Has Connected" self.factory.clients.append(self) print"clients are ",self.factory.clients self.transport.write('Hello,Welcome to the telnet chat to sign in type aim:YOUR NAME HERE to send a messsage type msg:YOURMESSAGE '+'\n') def connectionLost(self,reason): self.factory.clients.remove(self) self.transport.write('Somebody was disconnected from the server') def dataReceived(self,data): #print "data is",data a = data.split(':') if len(a) > 1: command = a[0] content = a[1] msg="" if command =="iam": self.name + "has joined" elif command == "msg": ma=sg = self.name + ":" +content print msg for c in self.factory.clients: c.message(msg) def message(self,message): self.transport.write(message + '\n') factory = Factory() factory.protocol = ChatServer factory.clients = [] reactor.listenTCP(80,factory) print "Iphone Chat server started" reactor.run() The above code is running succesfully...but when i connect the client (by typing telnet localhost 80) to this chatserver and try to write message ,connection gets lost and following errors occurs : Iphone Chat server started A Client Has Connected clients are [<__main__.ChatServer instance at 0x024AC0A8>] Unhandled Error Traceback (most recent call last): File "C:\Python27\lib\site-packages\twisted\python\log.py", line 84, in callWithLogger return callWithContext({"system": lp}, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\log.py", line 69, in callWithContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\context.py", line 118, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "C:\Python27\lib\site-packages\twisted\python\context.py", line 81, in callWithContext return func(*args,**kw) --- --- File "C:\Python27\lib\site-packages\twisted\internet\selectreactor.py", line 150, in _doReadOrWrite why = getattr(selectable, method)() File "C:\Python27\lib\site-packages\twisted\internet\tcp.py", line 199, in doRead rval = self.protocol.dataReceived(data) File "D:\chatserverultimate.py", line 21, in dataReceived content = a[1] exceptions.IndexError: list index out of range Where am I going wrong?

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  • Namespace scoped aliases for generic types in C#

    - by TN
    Let's have a following example: public class X { } public class Y { } public class Z { } public delegate IDictionary<Y, IList<Z>> Bar(IList<X> x, int i); public interface IFoo { // ... Bar Bar { get; } } public class Foo : IFoo { // ... public Bar Bar { get { return null; //... } } } void Main() { IFoo foo; //= ... IEnumerable<IList<X>> source; //= ... var results = source.Select(foo.Bar); } The compiler says: The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. It's because, it cannot convert Bar to Func<IList<X>, int, IDictionary<Y, IList<Z>>>. It would be great if I could create type namespace scoped type aliases for generic types in C#. Then I would define Bar not as a delegate, but rather I would define it as an namespace scoped alias for Func<IList<X>, int, IDictionary<Y, IList<Z>>>. public alias Bar = Func<IList<X>, int, IDictionary<Y, IList<Z>>>; I could then also define namespace scoped alias for e.g. IDictionary<Y, IList<Z>>. And if used appropriately:), it will make the code more readable. Now I have inline the generic types and the real code is not well readable:( Have you find the same trouble:)? Is there any good reason why it is not in C# 3.0? Or there is no good reason, it's just matter of money and/or time? EDIT: I know that I can use using, but it is not namespace based - not so convenient for my case.

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  • Passing functor and function pointers interchangeably using a templated method in C++

    - by metroxylon
    I currently have a templated class, with a templated method. Works great with functors, but having trouble compiling for functions. Foo.h template <typename T> class Foo { public: // Constructor, destructor, etc... template <typename Func> void bar(T x, Func f); }; template <typename T> template <typename Func> Foo::bar(T x, Func f) { /* some code here */ } Main.cpp #include "Foo.h" template <typename T> class Functor { public: Functor() {} void operator()(T x) { /* ... */ } private: /* some attributes here */ }; void Function(T x) { /* ... */ } int main() { Foo<int> foo; foo.bar(2, Functor); // No problem foo.bar(2, Function); // <unresolved overloaded function type> return 0; }

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  • Creating a sort function for a generic list

    - by Andrey
    I have a method for sorting generic lists by the object fields: public static IQueryable<T> SortTable<T>(IQueryable<T> q, string sortfield, bool ascending) { var p = Expression.Parameter(typeof(T), "p"); if (typeof(T).GetProperty(sortfield).PropertyType == typeof(int?)) { var x = Expression.Lambda<Func<T, int?>>(Expression.Property(p, sortfield), p); if (ascending) q = q.OrderBy(x); else q = q.OrderByDescending(x); } else if (typeof(T).GetProperty(sortfield).PropertyType == typeof(int)) { var x = Expression.Lambda<Func<T, int>>(Expression.Property(p, sortfield), p); if (ascending) q = q.OrderBy(x); else q = q.OrderByDescending(x); } else if (typeof(T).GetProperty(sortfield).PropertyType == typeof(DateTime)) { var x = Expression.Lambda<Func<T, DateTime>>(Expression.Property(p, sortfield), p); if (ascending) q = q.OrderBy(x); else q = q.OrderByDescending(x); } // many more for every type return q; } Is there any way I can collapse those ifs to a single generic statement? The main problem is that for the part Expression.Lambda<Func<T, int>> I am not sure how to write it generically.

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  • C# Generic Generics (A Serious Question)

    - by tahirhassan
    In C# I am trying to write code where I would be creating a Func delegate which is in itself generic. For example the following (non-Generic) delegate is returning an arbitrary string: Func<string> getString = () => "Hello!"; I on the other hand want to create a generic which acts similarly to generic methods. For example if I want a generic Func to return default(T) for a type T. I would imagine that I write code as follows: Func<T><T> getDefaultObject = <T>() => default(T); Then I would use it as getDefaultObject<string>() which would return null and if I were to write getDefaultObject<int>() would return 0. This question is not merely an academic excercise. I have found numerous places where I could have used this but I cannot get the syntax right. Is this possible? Are there any libraries which provide this sort of functionality?

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  • C++ Function pointers vs Switch

    - by Perfix
    What is faster: Function pointers or switch? The switch statement would have around 30 cases, consisting of enumarated unsigned ints from 0 to 30. I could do the following: class myType { FunctionEnum func; string argv[123]; int someOtherValue; }; // In another file: myType current; // Iterate through a vector containing lots of myTypes // ... for ( i=0; i < myVecSize; i ++ ) switch ( current.func ) { case 1: //... break; // ........ case 30: // blah break; } And go trough the switch with func every time. The good thing about switch would also be that my code is more organized than with 30 functions. Or I could do that (not so sure with that): class myType { myReturnType (*func); string argv[123]; int someOtherValue; }; I'd have 30 different functions then, at the beginning a pointer to one of them is assigned to myType. What is probably faster: Switch statement or function pointer? Calls per second: Around 10 million. I can't just test it out - that would require me to rewrite the whole thing. Currently using switch. I'm building an interpreter which I want to be faster than Python & Ruby - every clock cycle matters!

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  • Is method reference caching a good idea in Java 8?

    - by gexicide
    Consider I have code like the following: class Foo { Y func(X x) {...} void doSomethingWithAFunc(Function<X,Y> f){...} void hotFunction(){ doSomethingWithAFunc(this::func); } } Consider that hotFunction is called very often. Would it then be advisable to cache this::func, maybe like this: class Foo { Function<X,Y> f = this::func; ... void hotFunction(){ doSomethingWithAFunc(f); } } As far as my understanding of java method references goes, the Virtual Machine creates an object of an anonymous class when a method reference is used. Thus, caching the reference would create that object only once while the first approach creates it on each function call. Is this correct? Should method references that appear at hot positions in the code be cached or is the VM able to optimize this and make the caching superfluous? Is there a general best practice about this or is this highly VM-implemenation specific whether such caching is of any use?

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  • Getting rid of function's argument

    - by Max
    It is better to explain my intention with code. So right now I have the following code: class A, IInterfaceUsedByB { } class B { void func(A someObject) { func2(someObject, 1); func3(someObject, "string"); func4(someObject, new MyObject()); } func2(A someObject, int val); func3(A someObject, string val); func4(A someObject, C val); } Where func2, func3, func4 do need references to someObject. I want to change this to void func() { with(someObject, () => { func2(1); func3("string"); func4(new MyObject()); } ); } Or even better to void func(someObject) { func2(1); func3("string"); func4(new MyObject()); } So that I don't have to drag this someObject around, but I should still be able to use it inside func2,3,4. I can use any of the three languages (C#, F# or IronPython) for this. UPDATE In the ideal solution class B would be independent of A. func* functions only depend on a small interface of A consisting of 2 methods.

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  • Using .net 3.5 assemblies in asp.net 2.0 web application

    - by masterik
    I have an .net assembly build against 3.5 framework. This assembly has a class Foo with two method overrides: public class Foo { public T Set<T>(T value); public T Set<T>(Func<T> getValueFunc); } I'm referencing this assembly in my asp.net 2.0 web application to use first override of the Set method (without Func). But on build I get an error saying that I should reference System.Core to use System.Func delegate... but I'm not using this type... Is there a workaround to solve this? PS: There is no option to convert my web application targeting 3.5 framework.

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  • Dictionary<string,string> to Dictionary<Control,object> using IEnumerable<T>.Select()

    - by abatishchev
    I have a System.Collections.Generic.Dictionary<string, string> containing control ID and appropriate data column to data bind: var dic = new Dictionary<string, string> { { "Label1", "FooCount" }, { "Label2", "BarCount" } }; I use it that way: var row = ((DataRowView)FormView1.DataItem).Row; Dictionary<Control, object> newOne = dic.ToDictionary( k => FormView1.FindControl(k.Key)), k => row[k.Value]); So I'm using IEnumerable<T>.ToDictionary(Func<T>, Func<T>). Is it possbile to do the same using IEnumerable<T>.Select(Func<T>) ?

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  • C# threads - Posting messages between threads

    - by Harsha
    Hi All, I am working on a project which involves reusing as well as migrating some of the existing MFC code to C#. The current code in MFC, creates some threads and uses ::PostthreadeMessage() and ON_THREAD_MESSAGE(msg,func) for inter thread asynchronous communication through messages. ::PostthreadeMessage() - sends a message to a particular thread id. ON_THREAD_MESSAGE(msg,func) - calls the function(func) when a message(msg) is received. Since i am not much aware of the threading interfaces in C#, i tried to search for similar API's in C#, but was not able to find any. It would be great, if somebody can help me in finding the appropriate functions for this purpose in C# Thanks, Harsha

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  • Actionscript 3 introspection -- function names

    - by Markus O'reilly
    I am trying to iterate through each of the members of an object. For each member, I check to see if it is a function or not. If it is a function, I want to get the name of it and perform some logic based on the name of the function. I don't know if this is even possible though. Is it? Any tips? example: var mems: Object = getMemberNames(obj, true); for each(mem: Object in members) { if(!(mem is Function)) continue; var func: Function = Function(mem); //I want something like this: if(func.getName().startsWith("xxxx")) { func.call(...); } } I'm having a hard time finding much on doing this. Thanks for the help.

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  • Invoke "internal extern" constructor using reflections

    - by Riz
    Hi, I have following class (as seen through reflector) public class W : IDisposable { public W(string s); public W(string s, byte[] data); // more constructors [MethodImpl(MethodImplOptions.InternalCall)] internal extern W(string s, int i); public static W Func(string s, int i); } I am trying to call "internal extern" constructor or Func using reflections MethodInfo dynMethod = typeof(W).GetMethod("Func", BindingFlags.Static); object[] argVals = new object[] { "hi", 1 }; dynMethod.Invoke(null, argVals); and Type type = typeof(W); Type[] argTypes = new Type[] { typeof(System.String), typeof(System.Int32) }; ConstructorInfo cInfo = type.GetConstructor(BindingFlags.InvokeMethod | BindingFlags.NonPublic, null, argTypes, null); object[] argVals = new object[] { "hi", 1 }; dynMethod.Invoke(null, argVals); unfortunantly both variants rise NullReferenceException when trying to Invoke, so, I must be doing something wrong?

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  • Dynamic function docstring

    - by Tom Aldcroft
    I'd like to write a python function that has a dynamically created docstring. In essence for a function func() I want func.__doc__ to be a descriptor that calls a custom __get__ function create the docstring on request. Then help(func) should return the dynamically generated docstring. The context here is to write a python package wrapping a large number of command line tools in an existing analysis package. Each tool becomes a similarly named module function (created via function factory and inserted into the module namespace), with the function documentation and interface arguments dynamically generated via the analysis package.

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  • c# Attribute Question

    - by Petoj
    Well i need some help here i don't know how to solve this problem. the function of the attribute is to determine if the function can be run... So what i need is the following: The consumer of the attribute should be able to determine if it can be executed. The owner of the attribute should be able to tell the consumer that now it can/can't be executed (like a event). It must have a simple syntax. This is what i have so far but it only implements point 1, 3. [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)] public class ExecuteMethodAttribute : Attribute { private Func<object, bool> canExecute; public Func<object, bool> CanExecute { get { return canExecute; } } public ExecuteMethodAttribute() { } public ExecuteMethodAttribute(Func<object, bool> canExecute) { this.canExecute = canExecute; } }

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  • Cast from Void* to TYPE* using C++ style cast: static_cast or reinterpret_cast

    - by David Relihan
    So if your converting from Void* to Type* or from Type* to Void* should you use: void func(void *p) { Params *params = static_cast<Params*>(p); } or void func(void *p) { Params *params = reinterpret_cast<Params*>(p); } To me static_cast seems the more correct but I've seen both used for the same purpose. Also, does the direction of the conversion matter. i.e. should I still use static_cast for: _beginthread(func,0,static_cast<void*>(params) I have read the other questions on C++ style casting but I'm still not sure what the correct way is for this scenario (I think it is static_cast)

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  • Passing list and dictionary type parameter with Python

    - by prosseek
    When I run this code def func(x, y, *w, **z): print x print y if w: print w if z: print z else: print "None" func(10,20, 1,2,3,{'k':'a'}) I get the result as follows. 10 20 (1, 2, 3, {'k': 'a'}) None But, I expected as follows, I mean the list parameters (1,2,3) matching *w, and dictionary matching **z. 10 20 (1,2,3) {'k':'a'} Q : What went wrong? How can I pass the list and dictionary as parameters? Added func(10,20, 10,20,30, k='a') seems to be working

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  • python- scipy optimization

    - by pear
    In scipy fmin_slsqp (Sequential Least Squares Quadratic Programming), I tried reading the code 'slsqp.py' provided with the scipy package, to find what are the criteria to get the exit_modes 0? I cannot find which statements in the code produce this exit mode? Please help me 'slsqp.py' code as follows, exit_modes = { -1 : "Gradient evaluation required (g & a)", 0 : "Optimization terminated successfully.", 1 : "Function evaluation required (f & c)", 2 : "More equality constraints than independent variables", 3 : "More than 3*n iterations in LSQ subproblem", 4 : "Inequality constraints incompatible", 5 : "Singular matrix E in LSQ subproblem", 6 : "Singular matrix C in LSQ subproblem", 7 : "Rank-deficient equality constraint subproblem HFTI", 8 : "Positive directional derivative for linesearch", 9 : "Iteration limit exceeded" } def fmin_slsqp( func, x0 , eqcons=[], f_eqcons=None, ieqcons=[], f_ieqcons=None, bounds = [], fprime = None, fprime_eqcons=None, fprime_ieqcons=None, args = (), iter = 100, acc = 1.0E-6, iprint = 1, full_output = 0, epsilon = _epsilon ): # Now do a lot of function wrapping # Wrap func feval, func = wrap_function(func, args) # Wrap fprime, if provided, or approx_fprime if not if fprime: geval, fprime = wrap_function(fprime,args) else: geval, fprime = wrap_function(approx_fprime,(func,epsilon)) if f_eqcons: # Equality constraints provided via f_eqcons ceval, f_eqcons = wrap_function(f_eqcons,args) if fprime_eqcons: # Wrap fprime_eqcons geval, fprime_eqcons = wrap_function(fprime_eqcons,args) else: # Wrap approx_jacobian geval, fprime_eqcons = wrap_function(approx_jacobian, (f_eqcons,epsilon)) else: # Equality constraints provided via eqcons[] eqcons_prime = [] for i in range(len(eqcons)): eqcons_prime.append(None) if eqcons[i]: # Wrap eqcons and eqcons_prime ceval, eqcons[i] = wrap_function(eqcons[i],args) geval, eqcons_prime[i] = wrap_function(approx_fprime, (eqcons[i],epsilon)) if f_ieqcons: # Inequality constraints provided via f_ieqcons ceval, f_ieqcons = wrap_function(f_ieqcons,args) if fprime_ieqcons: # Wrap fprime_ieqcons geval, fprime_ieqcons = wrap_function(fprime_ieqcons,args) else: # Wrap approx_jacobian geval, fprime_ieqcons = wrap_function(approx_jacobian, (f_ieqcons,epsilon)) else: # Inequality constraints provided via ieqcons[] ieqcons_prime = [] for i in range(len(ieqcons)): ieqcons_prime.append(None) if ieqcons[i]: # Wrap ieqcons and ieqcons_prime ceval, ieqcons[i] = wrap_function(ieqcons[i],args) geval, ieqcons_prime[i] = wrap_function(approx_fprime, (ieqcons[i],epsilon)) # Transform x0 into an array. x = asfarray(x0).flatten() # Set the parameters that SLSQP will need # meq = The number of equality constraints if f_eqcons: meq = len(f_eqcons(x)) else: meq = len(eqcons) if f_ieqcons: mieq = len(f_ieqcons(x)) else: mieq = len(ieqcons) # m = The total number of constraints m = meq + mieq # la = The number of constraints, or 1 if there are no constraints la = array([1,m]).max() # n = The number of independent variables n = len(x) # Define the workspaces for SLSQP n1 = n+1 mineq = m - meq + n1 + n1 len_w = (3*n1+m)*(n1+1)+(n1-meq+1)*(mineq+2) + 2*mineq+(n1+mineq)*(n1-meq) \ + 2*meq + n1 +(n+1)*n/2 + 2*m + 3*n + 3*n1 + 1 len_jw = mineq w = zeros(len_w) jw = zeros(len_jw) # Decompose bounds into xl and xu if len(bounds) == 0: bounds = [(-1.0E12, 1.0E12) for i in range(n)] elif len(bounds) != n: raise IndexError, \ 'SLSQP Error: If bounds is specified, len(bounds) == len(x0)' else: for i in range(len(bounds)): if bounds[i][0] > bounds[i][1]: raise ValueError, \ 'SLSQP Error: lb > ub in bounds[' + str(i) +'] ' + str(bounds[4]) xl = array( [ b[0] for b in bounds ] ) xu = array( [ b[1] for b in bounds ] ) # Initialize the iteration counter and the mode value mode = array(0,int) acc = array(acc,float) majiter = array(iter,int) majiter_prev = 0 # Print the header if iprint >= 2 if iprint >= 2: print "%5s %5s %16s %16s" % ("NIT","FC","OBJFUN","GNORM") while 1: if mode == 0 or mode == 1: # objective and constraint evaluation requird # Compute objective function fx = func(x) # Compute the constraints if f_eqcons: c_eq = f_eqcons(x) else: c_eq = array([ eqcons[i](x) for i in range(meq) ]) if f_ieqcons: c_ieq = f_ieqcons(x) else: c_ieq = array([ ieqcons[i](x) for i in range(len(ieqcons)) ]) # Now combine c_eq and c_ieq into a single matrix if m == 0: # no constraints c = zeros([la]) else: # constraints exist if meq > 0 and mieq == 0: # only equality constraints c = c_eq if meq == 0 and mieq > 0: # only inequality constraints c = c_ieq if meq > 0 and mieq > 0: # both equality and inequality constraints exist c = append(c_eq, c_ieq) if mode == 0 or mode == -1: # gradient evaluation required # Compute the derivatives of the objective function # For some reason SLSQP wants g dimensioned to n+1 g = append(fprime(x),0.0) # Compute the normals of the constraints if fprime_eqcons: a_eq = fprime_eqcons(x) else: a_eq = zeros([meq,n]) for i in range(meq): a_eq[i] = eqcons_prime[i](x) if fprime_ieqcons: a_ieq = fprime_ieqcons(x) else: a_ieq = zeros([mieq,n]) for i in range(mieq): a_ieq[i] = ieqcons_prime[i](x) # Now combine a_eq and a_ieq into a single a matrix if m == 0: # no constraints a = zeros([la,n]) elif meq > 0 and mieq == 0: # only equality constraints a = a_eq elif meq == 0 and mieq > 0: # only inequality constraints a = a_ieq elif meq > 0 and mieq > 0: # both equality and inequality constraints exist a = vstack((a_eq,a_ieq)) a = concatenate((a,zeros([la,1])),1) # Call SLSQP slsqp(m, meq, x, xl, xu, fx, c, g, a, acc, majiter, mode, w, jw) # Print the status of the current iterate if iprint > 2 and the # major iteration has incremented if iprint >= 2 and majiter > majiter_prev: print "%5i %5i % 16.6E % 16.6E" % (majiter,feval[0], fx,linalg.norm(g)) # If exit mode is not -1 or 1, slsqp has completed if abs(mode) != 1: break majiter_prev = int(majiter) # Optimization loop complete. Print status if requested if iprint >= 1: print exit_modes[int(mode)] + " (Exit mode " + str(mode) + ')' print " Current function value:", fx print " Iterations:", majiter print " Function evaluations:", feval[0] print " Gradient evaluations:", geval[0] if not full_output: return x else: return [list(x), float(fx), int(majiter), int(mode), exit_modes[int(mode)] ]

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  • C# going nuts when I declare variables with the same name as the ones in a lambda

    - by Rubys
    I have the following code (generates a quadratic function given the a, b, and c) Func<double, double, double, Func<double, double>> funcGenerator = (a, b, c) => f => f * f * a + b * f + c; Up until now, lovely. But then, if i try to declare a variable named a, b, c or f, visual studio pops a "A local variable named 'f' could not be declared at this scope because it would give a different meaning to 'f' which is used in a child scope." Basically, this fails, and I have no idea why, because a child scope doesn't even make any sense. Func funcGenerator = (a, b, c) = f = f * f * a + b * f + c; var f = 3; // Fails var d = 3; // Fine What's going on here?

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