Tag: constraints

Feed: Planet PostgreSQL. Most of my readers will know about primary keys and all kinds of table constraints. However, only a few of you may have ever thought about the difference between a primary key and a UNIQUE constraint. Isn’t it all just the same? In both cases, PostgreSQL will create an index that avoids duplicate entries. So what is the difference? Let’s dig in and find out…What primary keys and UNIQUE constraints doThe following example shows both a primary key and a unique constraint: test=# CREATE TABLE t_sample (a int PRIMARY KEY, b int UNIQUE); CREATE TABLE test=# d ... Read More

Feed: R-bloggers. Author: Michael Mayer. library(farff) library(OpenML) library(dplyr) library(xgboost) set.seed(83454) rmse <- function(y, pred) { sqrt(mean((y-pred)^2)) } # Load King Country house prices dataset on OpenML # ID 42092, https://www.openml.org/d/42092 df <- getOMLDataSet(data.id = 42092)$data head(df) # Prepare df <- df %>% mutate( log_price = log(price), log_sqft_lot = log(sqft_lot), year = as.numeric(substr(date, 1, 4)), building_age = year - yr_built, zipcode = as.integer(as.character(zipcode)) ) # Define response and features y <- "log_price" x <- c("grade", "year", "building_age", "sqft_living", "log_sqft_lot", "bedrooms", "bathrooms", "floors", "zipcode", "lat", "long", "condition", "waterfront") m <- length(x) # random split ix <- sample(nrow(df), 0.8 * nrow(df)) y_test <- ... Read More

Feed: SAS Blogs. Author: Rick Wicklin. Sometimes we can learn as much from our mistakes as we do from our successes. Recently, I needed to solve an optimization problem for which the solution vector was a binary vector subject to a constraint. I was in a hurry. Without thinking much about what I was doing, I decided to eliminate the constraint by introducing a penalty term into the objective function. I then solved the unconstrained penalized optimization problem. A few days later, I thought further about what I had done. I had reformulated a constrained optimization problem as an ... Read More

Feed: Planet PostgreSQL. In PostgreSQL and many other relational databases, constraints are an integral part of the feature set. Many people are aware of primary keys, foreign keys, CHECK-constraints, table constraints and so on. However, from time to time, the situation is way more complicated. That’s when some more advanced techniques are needed to enforce integrity in the way it is desired by end users.In this post, we will elaborate on restrictions spanning more than one row. What does that mean? Let us envision a simple scenario: We want to store information about airplane ownership. In aviation, it happens more ... Read More

Feed: The Connector by Workato. Author: Anna Kelley; Your organization is in the API game, utilizing API connections to integrate and automate its services and processes. But are you maximizing the potential of those integrations? If you’re on the varsity squad, you might be used to the traditional SOAP (simple object access protocol) API playbook. It’s time to consider how REST APIs—which offer standardized, scalable, and high-performance integrations—can optimize your team’s performance.  There are instances in which a faster, more agile, and more lightweight group of players is who you need on the court to make the right play. These ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Roberto Quadrini. Epoch0: 1618000449 “Transform limits into constraints to create flexibility” — Roberto Quadrini Goal: Discuss solutions, methodologies, systems, projects to support the Energy Transition towards Energy Convergence Target: Operators, Customers, Regulators, Legislators, Inventors, Academics, Scientists, Enthusiasts Market: #EnergyTransition Power: [mW] TAG: #Epoch #Optimize #PowerMarket #Blockchain #Method #EnergyOptimization #DemandSideResponseAggregator #Electricity #EnergyTransition #DemandSide #ResponseSide #EnergyConvergence #CommoditiesAsAService #EnergyMarket #Supply #Demand #Validator #EU #Response #FlexibilityServices #Ledger #Pool #Consensus #Staking #Mining #EpochONE #MathModel #Algorithm #MachineLearning #DeepLearning #Artificialntelligence #Blockchain #ElectricalFlexibility #Resilience #EnergyCommunity #DemandResponse #GreenDeal #NegaWhEXchange Inspiration: #Aristotle, #GalileoGalilei, #LudwigVonMises #LuigiEinaudi#AbrahamCresques Ledger: Roberto Quadrini [IT] Validator: Stefano ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: OLIVIA CUTHBERT. The increasing constraints of the perimeter have opened up avenues for technological invention. Although there are some serious concerns regarding web applications' security, developments around the world have not stopped. However, this has resulted in the increased use of technology, providing companies with new ways of doing business and recent software trends.   In almost every industry sector, the market dynamics are changing, which has changed the phase of technology as we know it today. But it's not just technology and technology trends evolving; many things have changed this ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Alice Wright. Cloud accounting is the new technology that most companies and businesses are adopting. There is a big difference between cloud-hosting software and on-premises software. Similar way QuickBooks hosting is way different from the QuickBooks Desktop solution.  QuickBooks Desktop is a famous accounting software that has a broad impact on the accounting industry. With all its distinct features, QuickBooks Desktop has added progress to accounting businesses. But due to the rapidly changing technologies in accounting software demands consistent upgrade in QuickBooks Desktop. That is the one reason QuickBooks installed on ... Read More

Feed: R-bloggers. Author: finnstats. [This article was first published on Methods – finnstats, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. Linear optimization using R, in this tutorial we are going to discuss the linear optimization problems in R. Optimization is everything nowadays. We all have finite resources and time and we want to make the maximum profit out of that. Companies want to makes maximum profits based on limited resources they have, ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Kurt A Cagle. Several years ago, the typical company website fit into a predefined template - a home or landing page (usually talking about how innovative the company was), a products page, a business client testimonials page, a blog, and an "about us" page. However, as the number of products or services have multiplied, and as the demands for supporting those services have followed suit, your readers had to spend more time and energy finding appropriate content - and web managers had to focus more on keeping things organized than they ... Read More