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Questions tagged [modeling]

Modeling is the constructing and manipulating abstract (mathematical and/or graphical) representations of economic, engineering, manufacturing, social, and other types of situations and natural phenomenon, simulated with the help of a computer system.

Modeling is the construction and manipulation of abstract (mathematical and/or graphical) representations of economic, engineering, manufacturing, social, and other types of situations and natural phenomenon, simulated with the help of a computer system.

2023 questions
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How to get output of the nested loop in a data frame using r? And how to put a time loop?

I am new to r and work on boolean modelling - my nested loop gives output of 50 values of rtk in terms of 0 and 1, how to store this output in a dataframe , cbind is not working . Please help. 2. Also I would like to introduce a time loop ie if j =…
neha gopalakrishna
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Determine cardinlity of sets in GAMS

How can I determine the cardinality of a set in GAMS? Is there a keyword for this in GAMS? Suppose I have the following declaration: SET y /1 * 10/ ; I would like later in the model to make the asignment x = cardinality_of_y; How can I write…
Clement
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In JAGS, how does the stochastic node works?

...and what does the ~ sign mean compared to R in y[I] ~ dnorm(m[i],tau) vs y[I] <- dnorm(n,m[i],tau)? Consider the two lines of code: `for(I in 1:length(y)) { y[i] ~ dnorm(m[i],tau) #---> Jags code (stochastic node) m[i] = alpha + beta*(x[i] -…
Hello World
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How to use R models in Python

I have been working on an algorithm trading project where I used R to fit a random forest using historical data while the real-time trading system is in Python. I have fitted a model I'd like to use in R and am now wondering how can I use this…
DanielZuo
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Column-wise modeling in Gurobi using java

Is there a way to use a column-wise approach creating models in Gurobi? Using the java API, is possible to create columns (GRBColumn type) and you have to add constraints for each column. However, to create constraints, you must refer to a variable…
Gabriel Carvalho
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Free tool to generate all paths from a diagram

Good afternoon everyone, Dispite a lot of research on the web I didn't found a solution that meets my need. I need to find a free tool to modelize process (like BPMN, UML activity diagram) and generate all possible paths/combinations from the…
Royce
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adding quadratic term to logistic regression

I am trying to model a logistic regression with a couple of variables. I see that one of my variables has a quadratic trend, by plotting response by that variable and fitting a loess curve on it. So, I want to add a quadratic term to my logistic…
Jake L
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Ray tracing: Ellipsoid Hit function

We are working with shape generation using ray tracing. We believe that the hit function is not working appropriately. Currently, the "front" side of the ellipsoid is lit correctly. As the shape rotates, it has problems reflecting light. Example of…
Jes
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Minimizing a 6 dimensional problem with 3 constraints in python

We are given a problem that required the minimization of the cost of food for a student.She has to have calories (2,000 kcal), protein (55 g), and calcium (800 mg). and there are six types of food in total. We have to do this problem with the Python…
Li Ou
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How do I classify instances based on other instances within a group?

S.O. community - looking for a solution to a machine learning problem, if anybody can help it would be much appreciated: I would like to be able to apply a machine learning algorithm that assigns a classification of each instance BASED ON OTHER…
Bazza
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arima model, missing values

I am trying to estimate a quarterly arima model that explains the VIX index by one or more variables. My problem is that I need to difference and use log of my variables but because the dataset has some missing values, I get that lengths of 'x' and…
Ilias Geo
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Modelize multiple keywords in one field

I have some products that I want to index in an elasticsearch system. One of the field describing these products is the colour. For instance: Red Blue ... Some of my products can have two or more colours. Later on, I want to use facets…
Legisey
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Output "randomForest" with changing MeanDecreaseAccuracyValues

I have a question relating to the “randomForest” package in R. I am trying to build a model with ecological variables that best explain my species occupancy data for 41 sites in the field (which I have gathered from camera traps). My ultimate goal…
Fleur
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Netlogo - How to reflect turtles of patches depending on the scale-color

I'm trying to reflect turtles of patches depending on the pcolor scale-color. Basically, I'm using a slider in my modell, where the scale-color of patches can be adjusted from black to white. If a turtle in the shape of a ray hits a patch, another…
TobiCook
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Power BI - Parent Child Visualization

I would like to perform following visualization. Following is the table. +---------------+-------------+---------------+-------------+--------+-------------+-----------+--+ | Customer Name | Customer ID | Location Name | Location ID | Rating |…
Raghu
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