Optimization is the process of improving an existing program to make it work more efficiently or/and using less resources.

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Approaching Particle Swarm Optimization with optimization problem, how to use PSO with it?

I am learning Particle Swarm Optimization. The problem is to find the pair of number whose sum is lowest. Lets say we have some numbers z1,z2,z3,z4 Number Value z1 -2 z2 -3 z3 3 ...
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Is anti-aliasing still relevant in a high resolution display? [migrated]

The idea of anti-aliasing is to make edges look smooth so it is nicer for human eye to see. But lately with the availability of high-resolution monitor, with high density per inch, which some called ...
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Decision making algorithm

I'm currently solving an optimisation problem of my own design, just to experiment and learn a little something. Here's the concept: I have a user that starts at home. The objective of this user is ...
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110 views

Are there compilers which optimize the use of mathematical functions?

Today while programming I stumbled upon the following question - are there any compilers which optimize based on mathematical assumptions? For instance in cases like unsigned int i,b; (i,b not ...
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Are methods on non-pointer types subject to optimization

I've been enjoying go for the last couple of weeks. I suspect that, having some background in C, the fact that Go has pointers triggers my being concerned with optimization. Probably overly so. When I ...
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How to optimize iterable queries with external arguments

I will use C# here as an example, but my question is about any language. My question is from framework to compiler perspective (i.e the solution can be by implementing given idea inside compiler) ...
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1answer
88 views

Maximizing Value and Volume, minimizing weight - Knapsack

Trying out a Knapsack variant where the rules are Any item you take must fit completely in the bag Usable metrics of the bag are length(l),width(w),height(h) and you can assume that if the products ...
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2answers
146 views

Optimization problem where to start, what algorithms to use? [closed]

I have an optimization problem and I was wondering where to start from to be able resolve it. I think it can be solved with an NP-complete algorithm but I am not sure where to start from. The problem ...
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1answer
105 views

Improving sampling algorithm

I am having a bit of trouble designing a new feature at the moment. It is part of a resource management system. I was wondering if anyone has experience doing anything similar. I'll try to explain: ...
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3answers
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What can qualify for potential tail call recursion (TCO) optimization or tail recursion elimination (TRE)

Short question is: what can qualify for potential tail call recursion optimization (TCO) or tail recursion elimination (TRE) if the compiler or interpreter supports it. The summary of this question ...
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12answers
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When is optimization not premature and therefore not evil?

"Premature optimization is root of all evil" is something almost all of us have heard/read. What I am curious what kind of optimization not premature, i.e. at every stage of software development (high ...
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Program to select N integers with constraints [closed]

I need to write a program which takes 4 inputs as follows N = The number of integers to be generated (10 < N < 10000) Start = The minimum value of the integers (100 < Start) End = The ...
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Is premature optimization really the root of all evil?

A colleague of mine today committed a class called ThreadLocalFormat, which basically moved instances of Java Format classes into a thread local, since they are not thread safe and "relatively ...
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2answers
221 views

Can profiling be used to verify if optimization was successful?

I know that profiling is useful to identify bottlenecks and determining what parts of the code require how much time to execute. The latter isn't always very easy to track in the midst of other paths ...
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1answer
125 views

How to safely and cheaply delete a directory's contents that are constantly being deleted/overwritten

I'm coding something that will check a specific static location's directory, and if it exists, and a certain process has not run in n minutes, it deletes that directory's files and all sub-directory ...
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10answers
524 views

How often is software speed evident in the eyes of customers?

In theory, customers should be able to feel the software performance improvements from first-hand experience. In practice, sometimes the improvements are not noticible enough, such that in order to ...
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5answers
291 views

Can a pimpl variation be implemented without any performance penalty?

One of the issues of pimpl is the performance penalty of using it (additional memory allocation, non-contiguous data members, additional indirections, etc..). I would like to propose a variation on ...
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0answers
144 views

Combinatorial Optimization: Filling a Bag with Sand

I have an interesting "real-world" combinatorial optimization problem that I need to solve programmatically, however I have yet been able to whiteboard a good strategy. The task is similar to the ...
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4answers
5k views

Data Oriented Design - impractical with more than 1-2 structure “members”?

The usual example of Data Oriented Design is with the Ball structure: struct Ball { float Radius; float XYZ[3]; }; and then they make some algorithm that iterates a std::vector<Ball> ...
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How to measure algorithm accuracy?

I have a few optimization algorithms (for finding function minimum) and I'd like to check how good they are. Suppose I build test cases and compare the actual results to theoretical ones. What ...
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1answer
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Sorting an array based on another array's order, quickly [closed]

There are two arrays of maps. The first array contains maps of ID values in a specific order (but not necessarily either pure ASC or DESC ordering): // pseudo code first := [ {"id": 1}, ...
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1answer
106 views

Optimization: How much time saved is considered worth it? [closed]

I was reading up about branch predictions and cache misses, and have decided to read what every programmer should know about memory. But I'm not sure how much low level knowledge do I need to have to ...
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2answers
770 views

How is switch/case handled as to avoid comparisons to the case values?

I've read in multiple answers that switch/case avoids "unnecessary" comparisons, but I never learned this in college, and I'm a little stumped on how the program would figure out which case to jump to ...
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31answers
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Is micro-optimisation important when coding?

I recently asked a question on Stack Overflow to find out why isset() was faster than strlen() in PHP. This raised questions around the importance of readable code and whether performance improvements ...
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1answer
63 views

Multiple variable assignment vs HashTable lookup

I'm writing a CUIT ( Coded UI Test ) and I'm replacing variables with data fetched from a csv. Example: this.UIMap.IDBParams.UITboxFsEditText = TestContext.DataRow["num_fs"].ToString(); ...
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storing single character value use string or int C# [closed]

While storing single character value for the purpose of status, gender, delete_flag etc. which is better data type string or int. Suppose :: status = A/I or status = 1/0 gender = M/F or gender = 1/0 ...
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Do nested conditionals have a significant performance impact? [duplicate]

This is a question that lives in my mind from a long time. Does the use of multiple nested conditional statements impact the performance of a taken code? So far I know that programmers have created a ...
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How to distribute the number of elements in a bucket so that it is Within a Range - Algorithm

I have been solving a problem where in say I have 50 elements n1, n2, n3, ... , n50 Now I have a limited number of buckets, say 5 buckets and the bucket can hold a range from , say 100 to 150 only ...
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11answers
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Is it always wrong to optimize before profiling? [duplicate]

I see the mantra of "profiling before optimization" repeated again and again here, on SO, and elsewhere. Although I certainly use profiling tools, I'm only occasionally surprised by the results. It ...
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422 views

Efficient algorithm for Virtual Machine(VM) Consolidation in Cloud

PROBLEM: We have N physical machines(PMs) each with ram Ri, cpu Ci and a set of currently scheduled VMs each with ram requirement ri and ci respectively Moving(Migrating) any VM from one PM to ...
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Cost of cache coherency/sharing data across multiple cores?

If I have two CPU cores, one is writing a particular cache line and the other core wishes to Read Write the same cache line, what are the costs (in cycles) for doing so? I am a little unsure ...
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3answers
75 views

Premature memoization on obvious cases

In the code below there will be several instances of MainClass. class MainClass(object): def f(self, x): # expensive operations. # ... return 'something' Each instance ...
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2answers
253 views

Do we really need auto-vectorization?

I am trying to understand automatic parallelization and a special case of that is auto vectorization. As I understand it auto-vectorization is more or less: The compiler takes parts of the code which ...
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How do you avoid dominant solutions in multi-objective simulated annealing?

Imagine an RPG game were you can cary N items, and you want to maximise your damage, attack speed and armour, given a set of items. I implemented simulated annealing where a permutation simply ...
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Linking two or more different programming languages

I would like to ask how optimizer software written in C/C++ can be linked to simulator software written in FORTRAN or any other language. I have copied the section of journal article of Singh and ...
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4answers
448 views

When should code favour optimization over readability and ease-of-use?

I am in the process of designing a small library, where one of my design goals is that the API should be as close to the domain language as possible. While working on the design, I've noticed that ...
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How do I traverse a tree without using recursion?

I have a very large in memory node tree and need to traverse the tree. Passing the returned values of each child node to their parent node. This has to be done until all the nodes have their data ...
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Microcontroller oLED Display Buffering Optimizations or Alternatives For Speed?

I'm developing a UI/Layout for a 128 x 64 oLED Monochrome Pixel Display. I've got a small netMF microcontroller driving the display via SPI at 40mhz. I'm using some basic methods, like these here, to ...
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5answers
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Efficient methods for storing tens of millions of objects for querying, with a high number of inserts per second?

This is basically a logging/counting application that is counting the number of packets and counting the type of packet, etc. on a p2p chat network. This equates to about 4-6 million packets in a 5 ...
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2answers
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Work out which parcel deliveries we ship ourselves and which we outsource

Firstly, I hope I'm asking this in the right place. I work for a large online retailer in UK. We ship approaching 2000 orders each day and are growing very quickly. We currently use multiple delivery ...
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80 views

Optimizing instant notifications

Scenario To deliver instant notifications to the client, I'm sending an AJAX request to a PHP page that checks if there are new notifications: if there are, it outputs them, otherwise it sleeps for ...
3
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1answer
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Can fast, optimized server calls collapse a server?

I've followed a series of optimizations to make our APIs faster. We microoptimized a lot of PHP code to faster, native methods, we unsed variables where they were not being used anymore, and basically ...
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My algorithm that extracts the largest box that can be made from smaller boxes, is too slow

Imagine a cube based world (such as Minecraft, Trove, or Cube World) where everything is made up of identically sized cubes and all the cubes are of the same kind. The goal is to represent the world ...
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2answers
440 views

How small is the footprint of a small C compiler?

This week I could optimize using a reduced C library that allowed a drastic shrinkage in code size - from about 60 K to about 6 K and then we could load the code in the 8 K on-chip memory of an FPGA ...
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Reducing a sequence of array modification operations (insert, sort, replace, remove)

Given a plain array of values, e.g. ["Apple", "Orange", "Banana", "Strawberry"] and a list of operations from the set of [insert, delete, sort and replace], e.g. [ {cmd: "insert", index: 2, ...
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0answers
44 views

Optimizing trigram look ups with wildcards

I am working on creating a spell-checking service for Android (note: this is a platform- and language-neutral question) for Asturian, a minority Romance language. We're using hunspell as the base but ...
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Approaches to combinatorial optimization problem

Problem I have the following combinatorial optimization problem: A set of applications need to be distributed among a set of nodes. Each node has a capacity and each application has a required ...
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Feasible solution on the constructions phase of GRASP

I am learning about the GRASP (Greedy Randomized Adaptive Search) meta-heuristics. From what I understood, GRASP is based on two main phases. The first one: Construct a initial solution based on ...
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Is serving a single document from a server to a browser slower than serving multiple documents?

I was looking into how to optimize web pages and the biggest way (code-wise) to optimize a website is to reduce the number of requests a browser has to make to your web server to get the full page. ...
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Algorithm for comparing hundreds of similar, but not identical documents

I have seen similar questions about text comparison, but none on such a large scale. I have a client with two sets of recordings of speeches, 250 and 550 recordings each. Each of the recordings in ...