# Archive for category: Concepts and methods

## Preparing models for use in Real-Time

A “Real-Time” function exists in the Claytex Library to ease the simulation of a model in real-time. This function allows to set number flags that are available in Dymola for inline integration and to improve performance for real-time simulation.  Figure 1: Real-time function from the Claytex library Inline integration is...

## Using the Onboard Eigenvalue Function

This article introduces the use of the Dymola function for calculating eigenvalues, with syntax, inputs and interpretation of outputs. It’s also intended to present some examples of diagrams produced in the software that can provide insight into linear systems, and explain a little about what eigenvectors and their eigenvalues...

## Directories, Folders & Files From Dymola

Using & Creating Directories The working directory is the location on the computer in which Dymola runs and writes various files and of course the output file containing relevant trajectories of variables. It’s possible to find out, or alter which directory this is at some point during a simulation...

## Using DynamicSelect in Icons

DynamicSelect is a feature which allows the user to dynamically change aspects of the model during simulation. The function syntax is as follows: name of graphical feature = DynamicSelect (editing state, dynamic state)   Where any graphical feature, such as coordinates, colour, text, etc., in graphical annotations can be...

## Where to start when trying to improve simulation speed

How to find where and when events happened: an application of event reduction on heat transfer algorithms. Discrete events generally cause simulation to slow down because a solver will have to reinitialise the state variables via a number of iterations before a feasible numerical solution is reached. As the...

## Components array utility in hydraulic modelling

A component or object array could be quite useful if we want to create multiple objects arranged in parallel or series with each other. Component arrays are therefore also useful for being able to discretise or scale components in a convenient way. For example: multiple rotational springs and inertias...

## Splitting models into subsystems

The previous version of Dymola incorporated the possibility to create a submodel from some of the components of a model (this is the link to the corresponding article). This feature has been extended now and allows the creation of base classes. The procedure is completely analogous: 1. Select the...

## How to check your library using the Model Management option

Have you ever wanted to perform a regression test on a library you have created? Model Management, an optional library available in Dymola, could provide the solution. This article will highlight the key features of the Model Management library for checking your library. When you open the Model Management...

## New in Dymola 2013 – Submodel aggregation

A useful new feature in Dymola 2013 is submodel aggregation,which allows you to quickly create a new submodel from a group of components within an existing model.  This feature provides an alternative method for creating subsystem models to that described in the earlier article Creating and using subsystems. To...