Commit 1b11eb24 authored by Markus Klinik's avatar Markus Klinik
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example with conflicting objectives

parent a9b7fac2
\section{Examples}
\label{sec:examples}
\Cref{fig:conflict-quality-makespan} illustrate the effect of weights on conflicting objectives.
This instance has six resources and 15 tasks.
There is only one capability requirement \emph{C} and all resources have this capability, which means all resources can execute all tasks.
In this example resource 1 has quality 1 for all tasks, resource 2 has quality 2 and so on, which means that resource 6 has the highest quality.
The makespan, which is the time from the start of the first task to the end of the last, is in conflict with the quality of the assigned resources.
Assigning all tasks to resource 6 gives the best quality, but also the longest makespan.
\Cref{fig:conflict1} shows that with equal weights, the scheduler tries to assign as many tasks as possible to resource 6.
Some tasks are assigned to resource 5, which is an artefact of the probabilistic nature of our algorithm.
Letting it run for a longer time eventually finds solutions where all tasks are assigned to resource 6.
\Cref{fig:conflict7,fig:conflict15} show that as we increase the weight of the makespan, the scheduler tries to assign more tasks to resources with lower quality, thereby decreasing the makespan.
% how to put my Gantt chart into latex:
% 1. copy svg from firefox view source into .svg file
% 2. inkscape -D -z --file=mySVG.svg --export-pdf=myPDF.pdf --export-latex
......@@ -26,7 +39,7 @@
\def\svgwidth{1.0\textwidth}
\sffamily
\input{conflict7.pdf_tex}
\caption{Makespan weight = 7.0}
\caption{Makespan weight = 8.0}
\label{fig:conflict7}
\end{subfigure}
\hspace{7.0em}
......@@ -38,6 +51,9 @@
\label{fig:conflict15}
\end{subfigure}
\caption{foobar}
\label{fig:foobar}
\caption{An instance to demonstrate the conflict between quality and makespan.
Resource r6 has the highest quality, the scheduler prefers assigning tasks to it.
As the weight of the makespan grows, the scheduler assigns more tasks to resources with lower quality.
}
\label{fig:conflict-quality-makespan}
\end{figure*}
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