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main
...
6-solve-pr
1
.gitignore
vendored
1
.gitignore
vendored
@ -43,5 +43,4 @@
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src/*
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src/*
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!src/Makefile
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!src/Makefile
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!src/*.cpp
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!src/*.cpp
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!src/*.hpp
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!src/*.py
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!src/*.py
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33
README.md
33
README.md
@ -3,36 +3,3 @@
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## Practical information
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## Practical information
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- [Project](https://anderkve.github.io/FYS3150/book/projects/project1.html)
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- [Project](https://anderkve.github.io/FYS3150/book/projects/project1.html)
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## How to compile C++ code
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Make sure that you are inside the **src** directory before compiling the code.
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Now you can execute the command shown under to compile:
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```
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make
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```
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This will create object files and link them together into 2 executable files.
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These files are called **main** and **analyticPlot**.
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To run them, you can simply use the commands below:
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```
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./main
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```
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```
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./analyticPlot
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```
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## How to generate plots
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For generating the plots, there are 4 Python scripts.
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You can run each one of them by using this command:
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```
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python <PythonFile>
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```
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The plots will be saved inside **latex/images**.
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@ -80,7 +80,7 @@
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\begin{document}
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\begin{document}
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\title{Project 1} % self-explanatory
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\title{Project 1} % self-explanatory
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\author{Cory Alexander Balaton \& Janita Ovidie Sandtrøen Willumsen} % self-explanatory
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\author{Cory Balaton \& Janita Willumsen} % self-explanatory
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\date{\today} % self-explanatory
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\date{\today} % self-explanatory
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\noaffiliation % ignore this, but keep it.
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\noaffiliation % ignore this, but keep it.
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@ -107,6 +107,4 @@
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\input{problems/problem9}
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\input{problems/problem9}
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\input{problems/problem10}
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\end{document}
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\end{document}
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@ -40,5 +40,5 @@ Using the values that we found for $c_1$ and $c_2$, we get
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\begin{align*}
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\begin{align*}
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u(x) &= -e^{-10x} + (e^{-10} - 1) x + 1 \\
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u(x) &= -e^{-10x} + (e^{-10} - 1) x + 1 \\
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&= 1 - (1 - e^{-10})x - e^{-10x}
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&= 1 - (1 - e^{-10}) - e^{-10x}
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\end{align*}
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\end{align*}
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@ -1,8 +1,3 @@
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\section*{Problem 10}
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\section*{Problem 10}
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% Time and show result, and link to relevant files
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% Time and show result, and link to relevant files
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\begin{figure}[H]
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\centering
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\includegraphics[width=0.7\linewidth]{images/problem10.pdf}
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\caption{Timing of general algorithm vs. special for step sizes $n_{steps}$}
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\end{figure}
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@ -6,8 +6,6 @@ Point generator code: https://github.uio.no/FYS3150-G2-203/Project-1/blob/main/s
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Plotting code: https://github.uio.no/FYS3150-G2-2023/Project-1/blob/main/src/analyticPlot.py
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Plotting code: https://github.uio.no/FYS3150-G2-2023/Project-1/blob/main/src/analyticPlot.py
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\begin{figure}[H]
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Here is the plot of the analytical solution for $u(x)$.
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\centering
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\includegraphics[width=0.8\linewidth]{images/analytical_solution.pdf}
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\includegraphics[scale=.5]{analytical_solution.pdf}
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\caption{Plot of the analytical solution $u(x)$.}
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\end{figure}
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@ -1,6 +1,6 @@
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\section*{Problem 5}
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\section*{Problem 5}
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\subsection*{a \& b)}
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\subsection*{a)}
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$n = m - 2$ since when solving for $\vec{v}$, we are finding the solutions for all the points that are in between the boundaries and not the boundaries themselves. $\vec{v}^*$ on the other hand includes the boundary points.
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\subsection*{b)}
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@ -17,7 +17,6 @@ Following Thomas algorithm for gaussian elimination, we first perform a forward
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\State $n \leftarrow$ length of $\vec{b}$
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\State $n \leftarrow$ length of $\vec{b}$
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\State $\vec{\hat{b}}$, $\vec{\hat{g}} \leftarrow$ vectors of length $n$.
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\State $\vec{\hat{b}}$, $\vec{\hat{g}} \leftarrow$ vectors of length $n$.
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\State $\hat{b}_{1} \leftarrow b_{1}$ \Comment{Handle first element in main diagonal outside loop}
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\State $\hat{b}_{1} \leftarrow b_{1}$ \Comment{Handle first element in main diagonal outside loop}
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\State $\hat{g}_{1} \leftarrow g_{1}$
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\For{$i = 2, 3, ..., n$}
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\For{$i = 2, 3, ..., n$}
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\State $d \leftarrow \frac{a_{i}}{\hat{b}_{i-1}}$ \Comment{Calculating common expression}
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\State $d \leftarrow \frac{a_{i}}{\hat{b}_{i-1}}$ \Comment{Calculating common expression}
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\State $\hat{b}_{i} \leftarrow b_{i} - d \cdot c_{i-1}$
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\State $\hat{b}_{i} \leftarrow b_{i} - d \cdot c_{i-1}$
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@ -44,4 +43,4 @@ Following Thomas algorithm for gaussian elimination, we first perform a forward
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Counting the number of FLOPs for the general algorithm by looking at one procedure at a time.
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Counting the number of FLOPs for the general algorithm by looking at one procedure at a time.
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For every iteration of i in forward sweep we have 1 division, 2 multiplications, and 2 subtractions, resulting in $5(n-1)$ FLOPs.
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For every iteration of i in forward sweep we have 1 division, 2 multiplications, and 2 subtractions, resulting in $5(n-1)$ FLOPs.
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For backward sweep we have 1 division, and for every iteration of i we have 1 subtraction, 1 multiplication, and 1 division, resulting in $3(n-1)+1$ FLOPs.
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For backward sweep we have 1 division, and for every iteration of i we have 1 subtraction, 1 multiplication, and 1 division, resulting in $3(n-1)+1$ FLOPs.
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Total FLOPs for the general algorithm is $8(n-1)+1$.
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Total FLOPs for the general algorithm is $8(n-1)+1$.
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@ -1,14 +1,3 @@
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\section*{Problem 7}
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\section*{Problem 7}
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\subsection*{a)}
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% Link to relevant files on gh and possibly add some comments
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% Link to relevant files on gh and possibly add some comments
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The code can be found at https://github.uio.no/FYS3150-G2-2023/Project-1/blob/main/src/generalAlgorithm.cpp
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\subsection*{b)}
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Increasing the number of steps results in an approximation close to the exact solution.
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\begin{figure}[H]
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\centering
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\includegraphics[width=0.8\linewidth]{images/problem7.pdf}
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\caption{Plot showing the numeric solution of $u_{approx}$ for $n_{steps}$ and the exact solution $u_{exact}$.}
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\end{figure}
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@ -1,27 +1,3 @@
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\section*{Problem 8}
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\section*{Problem 8}
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%link to relvant files and show plots
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%link to relvant files and show plots
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\subsection*{a)}
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Increasing number of steps result in a decrease of absolute error.
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\begin{figure}[H]
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\centering
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\includegraphics[width=0.8\linewidth]{images/problem8_a.pdf}
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\caption{Absolute error for different step sizes $n_{steps}$.}
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\end{figure}
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\subsection*{b)}
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Increasing number of steps also result in a decrease of absolute error.
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\begin{figure}[H]
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\centering
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\includegraphics[width=0.8\linewidth]{images/problem8_b.pdf}
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\caption{Relative error for different step sizes $n_{steps}$.}
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\end{figure}
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\subsection*{c)}
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Increasing number of steps result in a decrease of maximum relative error, up to a certain number of steps. At $n_{steps} \approx 10^{5}$ the maximumrelative error increase.
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This can be related to loss of numerical precicion when step size is small.
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\begin{figure}[H]
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\centering
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\includegraphics[width=0.7\linewidth]{images/problem8_c.pdf}
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\caption{Maximum relative error for each step sizes $n_{steps}$.}
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\end{figure}
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@ -1,55 +1,3 @@
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\section*{Problem 9}
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\section*{Problem 9}
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\subsection*{a)}
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% Show the algorithm, then calculate FLOPs, then link to relevant files
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% Specialize algorithm
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The special algorithm does not require the values of all $a_{i}$, $b_{i}$, $c_{i}$.
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We find the values of $\hat{b}_{i}$ from simplifying the general case
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\begin{align*}
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\hat{b}_{i} &= b_{i} - \frac{a_{i} \cdot c_{i-1}}{\hat{b}_{i-1}} \\
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\hat{b}_{i} &= 2 - \frac{1}{\hat{b}_{i-1}}
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\end{align*}
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Calculating the first values to see a pattern
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\begin{align*}
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\hat{b}_{1} &= 2 \\
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\hat{b}_{2} &= 2 - \frac{1}{2} = \frac{3}{2} \\
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\hat{b}_{3} &= 2 - \frac{1}{\frac{3}{2}} = \frac{4}{3} \\
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\hat{b}_{4} &= 2 - \frac{1}{\frac{4}{3}} = \frac{5}{4} \\
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\vdots & \\
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\hat{b}_{i} &= \frac{i+1}{i} && \text{for $i = 1, 2, ..., n$}
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\end{align*}
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\begin{algorithm}[H]
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\caption{Special algorithm}\label{algo:special}
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\begin{algorithmic}
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\Procedure{Forward sweep}{$\vec{b}$}
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\State $n \leftarrow$ length of $\vec{b}$
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\State $\vec{\hat{b}}$, $\vec{\hat{g}} \leftarrow$ vectors of length $n$.
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\State $\hat{b}_{1} \leftarrow 2$ \Comment{Handle first element in main diagonal outside loop}
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\State $\hat{g}_{1} \leftarrow g_{1}$
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\For{$i = 2, 3, ..., n$}
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\State $\hat{b}_{i} \leftarrow \frac{i+1}{i}$
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\State $\hat{g}_{i} \leftarrow g_{i} + \frac{\hat{g}_{i-1}}{\hat{b}_{i-1}}$
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\EndFor
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\Return $\vec{\hat{b}}$, $\vec{\hat{g}}$
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\EndProcedure
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\Procedure{Backward sweep}{$\vec{\hat{b}}$, $\vec{\hat{g}}$}
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\State $n \leftarrow$ length of $\vec{\hat{b}}$
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\State $\vec{v} \leftarrow$ vector of length $n$.
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\State $v_{n} \leftarrow \frac{\hat{g}_{n}}{\hat{b}_{n}}$
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\For{$i = n-1, n-2, ..., 1$}
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\State $v_{i} \leftarrow \frac{\hat{g}_{i} + v_{i+1}}{\hat{b}_{i}}$
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\EndFor
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\Return $\vec{v}$
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\EndProcedure
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\end{algorithmic}
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\end{algorithm}
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\subsection*{b)}
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% Find FLOPs
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For every iteration of i in forward sweep we have 2 divisions, and 2 additions, resulting in $4(n-1)$ FLOPs.
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For backward sweep we have 1 division, and for every iteration of i we have 1 addition, and 1 division, resulting in $2(n-1)+1$ FLOPs.
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Total FLOPs for the special algorithm is $6(n-1)+1$.
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25
src/Makefile
25
src/Makefile
@ -1,30 +1,17 @@
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CC=g++
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CC=g++
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CCFLAGS= -std=c++11
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.PHONY: clean
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OBJS=generalAlgorithm.o specialAlgorithm.o funcs.o
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all: simpleFile analyticPlot
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EXEC=main analyticPlot
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simpleFile: simpleFile.o
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$(CC) -o $@ $^
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.PHONY: clean create_dirs
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all: create_dirs $(EXEC)
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main: main.o $(OBJS)
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$(CC) $(CCFLAGS) -o $@ $^
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analyticPlot: analyticPlot.o
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analyticPlot: analyticPlot.o
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$(CC) $(CCFLAGS) -o $@ $^
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$(CC) -o $@ $^
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%.o: %.cpp
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%.o: %.cpp
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$(CC) $(CCFLAGS) -c -o $@ $^
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$(CC) -c $< -o $@
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clean:
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clean:
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rm *.o
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rm *.o
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rm $(EXEC)
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rm -r output
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create_dirs:
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mkdir -p output/general
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mkdir -p output/special
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mkdir -p output/error
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@ -7,7 +7,7 @@
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#include <iomanip>
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#include <iomanip>
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#define RANGE 1000
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#define RANGE 1000
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#define FILENAME "output/analytical_solution.txt"
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#define FILENAME "analytical_solution.txt"
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|
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double u(double x);
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double u(double x);
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void generate_range(std::vector<double> &vec, double start, double stop, int n);
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void generate_range(std::vector<double> &vec, double start, double stop, int n);
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@ -2,11 +2,11 @@ import numpy as np
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import matplotlib.pyplot as plt
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import matplotlib.pyplot as plt
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def main():
|
def main():
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FILENAME = "../latex/images/analytical_solution.pdf"
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FILENAME = "analytical_solution.pdf"
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x = []
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x = []
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v = []
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v = []
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with open('output/analytical_solution.txt') as f:
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with open('analytical_solution.txt') as f:
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for line in f:
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for line in f:
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a, b = line.strip().split()
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a, b = line.strip().split()
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x.append(float(a))
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x.append(float(a))
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@ -1,38 +0,0 @@
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#include "funcs.hpp"
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double f(double x) {
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return 100*std::exp(-10*x);
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}
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double u(double x) {
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return 1. - (1. - std::exp(-10.))*x - std::exp(-10.*x);
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}
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void build_g_vec(int n_steps, arma::vec& g_vec) {
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g_vec.resize(n_steps-1);
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double step_size = 1./ (double) n_steps;
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for (int i=0; i < n_steps-1; i++) {
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g_vec(i) = step_size*step_size*f((i+1)*step_size);
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}
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}
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void build_arrays(
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int n_steps,
|
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arma::vec& sub_diag,
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arma::vec& main_diag,
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arma::vec& sup_diag,
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arma::vec& g_vec
|
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||||||
)
|
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{
|
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sub_diag.resize(n_steps-2);
|
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main_diag.resize(n_steps-1);
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sup_diag.resize(n_steps-2);
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|
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sub_diag.fill(-1);
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main_diag.fill(2);
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sup_diag.fill(-1);
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|
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build_g_vec(n_steps, g_vec);
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}
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@ -1,24 +0,0 @@
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#ifndef __FUNCS__
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#define __FUNCS__
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|
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#include <armadillo>
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#include <cmath>
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|
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#define PRECISION 8
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|
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#define N_STEPS_EXP 7
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|
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double f(double x);
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||||||
|
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double u(double x);
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||||||
|
|
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void build_g_vec(int n_steps, arma::vec& g_vec);
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||||||
|
|
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void build_arrays(
|
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int n_steps,
|
|
||||||
arma::vec& sub_diag,
|
|
||||||
arma::vec& main_diag,
|
|
||||||
arma::vec& sup_diag,
|
|
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arma::vec& g_vec
|
|
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);
|
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#endif
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@ -1,84 +0,0 @@
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#include "funcs.hpp"
|
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||||||
#include "generalAlgorithm.hpp"
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#include <cmath>
|
|
||||||
|
|
||||||
arma::vec& general_algorithm(
|
|
||||||
arma::vec& sub_diag,
|
|
||||||
arma::vec& main_diag,
|
|
||||||
arma::vec& sup_diag,
|
|
||||||
arma::vec& g_vec
|
|
||||||
)
|
|
||||||
{
|
|
||||||
int n = g_vec.n_elem;
|
|
||||||
double d;
|
|
||||||
|
|
||||||
for (int i = 1; i < n; i++) {
|
|
||||||
d = sub_diag(i-1) / main_diag(i-1);
|
|
||||||
main_diag(i) -= d*sup_diag(i-1);
|
|
||||||
g_vec(i) -= d*g_vec(i-1);
|
|
||||||
}
|
|
||||||
|
|
||||||
g_vec(n-1) /= main_diag(n-1);
|
|
||||||
|
|
||||||
for (int i = n-2; i >= 0; i--) {
|
|
||||||
g_vec(i) = (g_vec(i) - sup_diag(i) * g_vec(i+1)) / main_diag(i);
|
|
||||||
}
|
|
||||||
return g_vec;
|
|
||||||
}
|
|
||||||
|
|
||||||
void general_algorithm_main()
|
|
||||||
{
|
|
||||||
arma::vec sub_diag, main_diag, sup_diag, g_vec, v_vec;
|
|
||||||
std::ofstream ofile;
|
|
||||||
int steps;
|
|
||||||
double step_size;
|
|
||||||
|
|
||||||
for (int i = 0; i < N_STEPS_EXP; i++) {
|
|
||||||
steps = std::pow(10, i+1);
|
|
||||||
step_size = 1./(double) steps;
|
|
||||||
|
|
||||||
build_arrays(steps, sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
v_vec = general_algorithm(sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
ofile.open("output/general/out_" + std::to_string(steps) + ".txt");
|
|
||||||
|
|
||||||
for (int j=0; j < v_vec.n_elem; j++) {
|
|
||||||
ofile << std::setprecision(PRECISION) << std::scientific << step_size*(j+1) << ","
|
|
||||||
<< std::setprecision(PRECISION) << std::scientific << v_vec(j) << std::endl;
|
|
||||||
}
|
|
||||||
ofile.close();
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
void general_algorithm_error()
|
|
||||||
{
|
|
||||||
arma::vec sub_diag, main_diag, sup_diag, g_vec, v_vec;
|
|
||||||
std::ofstream ofile;
|
|
||||||
int steps;
|
|
||||||
double step_size, abs_err, rel_err, u_i, v_i;
|
|
||||||
|
|
||||||
for (int i=0; i < N_STEPS_EXP; i++) {
|
|
||||||
steps = std::pow(10, i+1);
|
|
||||||
step_size = 1./(double) steps;
|
|
||||||
|
|
||||||
build_arrays(steps, sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
v_vec = general_algorithm(sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
ofile.open("output/error/out_" + std::to_string(steps) + ".txt");
|
|
||||||
|
|
||||||
for (int j=0; j < v_vec.n_elem; j++) {
|
|
||||||
u_i = u(step_size*(j+1));
|
|
||||||
v_i = v_vec(j);
|
|
||||||
abs_err = u_i - v_i;
|
|
||||||
ofile << std::setprecision(PRECISION) << std::scientific
|
|
||||||
<< step_size*(j+1) << ","
|
|
||||||
<< std::setprecision(PRECISION) << std::scientific
|
|
||||||
<< std::log10(std::abs(abs_err)) << ","
|
|
||||||
<< std::setprecision(PRECISION) << std::scientific
|
|
||||||
<< std::log10(std::abs(abs_err/u_i)) << std::endl;
|
|
||||||
}
|
|
||||||
ofile.close();
|
|
||||||
}
|
|
||||||
}
|
|
||||||
@ -1,18 +0,0 @@
|
|||||||
#ifndef __GENERAL_ALG__
|
|
||||||
#define __GENERAL_ALG__
|
|
||||||
|
|
||||||
#include <armadillo>
|
|
||||||
#include <iomanip>
|
|
||||||
|
|
||||||
arma::vec& general_algorithm(
|
|
||||||
arma::vec& sub_diag,
|
|
||||||
arma::vec& main_diag,
|
|
||||||
arma::vec& sup_diag,
|
|
||||||
arma::vec& g_vec
|
|
||||||
);
|
|
||||||
|
|
||||||
void general_algorithm_main();
|
|
||||||
|
|
||||||
void general_algorithm_error();
|
|
||||||
|
|
||||||
#endif
|
|
||||||
82
src/main.cpp
82
src/main.cpp
@ -1,68 +1,24 @@
|
|||||||
|
#include "GeneralAlgorithm.hpp"
|
||||||
#include <armadillo>
|
#include <armadillo>
|
||||||
#include <cmath>
|
#include <iostream>
|
||||||
#include <ctime>
|
|
||||||
#include <fstream>
|
|
||||||
#include <iomanip>
|
|
||||||
#include <ios>
|
|
||||||
#include <string>
|
|
||||||
|
|
||||||
#include "funcs.hpp"
|
double f(double x) {
|
||||||
#include "generalAlgorithm.hpp"
|
return 100. * std::exp(-10.*x);
|
||||||
#include "specialAlgorithm.hpp"
|
|
||||||
|
|
||||||
#define TIMING_ITERATIONS 5
|
|
||||||
|
|
||||||
void timing() {
|
|
||||||
arma::vec sub_diag, main_diag, sup_diag, g_vec;
|
|
||||||
int n_steps;
|
|
||||||
|
|
||||||
std::ofstream ofile;
|
|
||||||
ofile.open("output/timing.txt");
|
|
||||||
|
|
||||||
// Timing
|
|
||||||
for (int i=1; i < N_STEPS_EXP; i++) {
|
|
||||||
n_steps = std::pow(10, i);
|
|
||||||
clock_t g_1, g_2, s_1, s_2;
|
|
||||||
double g_res = 0, s_res = 0;
|
|
||||||
|
|
||||||
// Repeat a number of times to take an average
|
|
||||||
for (int j=0; j < TIMING_ITERATIONS; j++) {
|
|
||||||
|
|
||||||
build_arrays(n_steps, sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
g_1 = clock();
|
|
||||||
|
|
||||||
general_algorithm(sub_diag, main_diag, sup_diag, g_vec);
|
|
||||||
|
|
||||||
g_2 = clock();
|
|
||||||
|
|
||||||
g_res += (double) (g_2 - g_1) / CLOCKS_PER_SEC;
|
|
||||||
// Rebuild g_vec for the special alg
|
|
||||||
build_g_vec(n_steps, g_vec);
|
|
||||||
|
|
||||||
s_1 = clock();
|
|
||||||
|
|
||||||
special_algorithm(-1., 2., -1., g_vec);
|
|
||||||
|
|
||||||
s_2 = clock();
|
|
||||||
|
|
||||||
s_res += (double) (s_2 - s_1) / CLOCKS_PER_SEC;
|
|
||||||
|
|
||||||
}
|
|
||||||
// Write the average time to file
|
|
||||||
ofile
|
|
||||||
<< n_steps << ","
|
|
||||||
<< g_res / (double) TIMING_ITERATIONS << ","
|
|
||||||
<< s_res / (double) TIMING_ITERATIONS << std::endl;
|
|
||||||
}
|
|
||||||
|
|
||||||
ofile.close();
|
|
||||||
}
|
}
|
||||||
|
|
||||||
int main()
|
double a_sol(double x) {
|
||||||
{
|
return 1. - (1. - std::exp(-10)) * x - std::exp(-10*x);
|
||||||
timing();
|
}
|
||||||
general_algorithm_main();
|
|
||||||
general_algorithm_error();
|
int main() {
|
||||||
special_algorithm_main();
|
arma::mat A = arma::eye(3,3);
|
||||||
|
|
||||||
|
GeneralAlgorithm ga(3, &A, f, a_sol, 0., 1.);
|
||||||
|
|
||||||
|
ga.solve();
|
||||||
|
std::cout << "Time: " << ga.time(5) << std::endl;
|
||||||
|
ga.error();
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,30 +0,0 @@
|
|||||||
import matplotlib.pyplot as plt
|
|
||||||
import numpy as np
|
|
||||||
|
|
||||||
analytical_func = lambda x: 1 - (1 - np.exp(-10))*x - np.exp(-10*x)
|
|
||||||
|
|
||||||
def main():
|
|
||||||
for i in range(7):
|
|
||||||
x = []
|
|
||||||
y = []
|
|
||||||
x.append(0.)
|
|
||||||
y.append(0.)
|
|
||||||
with open(f"output/general/out_{10**(i+1)}.txt", "r") as f:
|
|
||||||
lines = f.readlines()
|
|
||||||
for line in lines:
|
|
||||||
x_i, y_i = line.strip().split(",")
|
|
||||||
x.append(float(x_i))
|
|
||||||
y.append(float(y_i))
|
|
||||||
|
|
||||||
x.append(1.)
|
|
||||||
y.append(0.)
|
|
||||||
|
|
||||||
plt.plot(x, y, label=f"n$_{{steps}} = 10^{i+1}$")
|
|
||||||
|
|
||||||
x = np.linspace(0, 1, 1001)
|
|
||||||
plt.plot(x, analytical_func(x), label=f"u$_{{exact}}$")
|
|
||||||
plt.legend()
|
|
||||||
plt.savefig("../latex/images/problem7.pdf")
|
|
||||||
|
|
||||||
if __name__ == "__main__":
|
|
||||||
main()
|
|
||||||
@ -1,40 +0,0 @@
|
|||||||
import matplotlib.pyplot as plt
|
|
||||||
|
|
||||||
# plt.rc('text', usetex=True)
|
|
||||||
# plt.rc('font', family='serif')
|
|
||||||
|
|
||||||
def main():
|
|
||||||
for i in range(7):
|
|
||||||
x = []
|
|
||||||
abs_err = []
|
|
||||||
rel_err = []
|
|
||||||
with open(f"output/error/out_{10**(i+1)}.txt", "r") as f:
|
|
||||||
lines = f.readlines()
|
|
||||||
for line in lines:
|
|
||||||
x_i, abs_err_i, rel_err_i = line.strip().split(",")
|
|
||||||
x.append(float(x_i))
|
|
||||||
abs_err.append(float(abs_err_i))
|
|
||||||
rel_err.append(float(rel_err_i))
|
|
||||||
|
|
||||||
plt.figure(1)
|
|
||||||
plt.plot(x, abs_err, label=f"n$_{{steps}} = 10^{i+1}$")
|
|
||||||
plt.figure(2)
|
|
||||||
plt.plot(x, rel_err, label=f"n$_{{steps}} = 10^{i+1}$")
|
|
||||||
|
|
||||||
plt.figure(3)
|
|
||||||
plt.plot(i+1, max(rel_err), marker="o", markersize=10)
|
|
||||||
|
|
||||||
plt.figure(1)
|
|
||||||
plt.legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
|
|
||||||
plt.figure(2)
|
|
||||||
plt.legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
|
|
||||||
|
|
||||||
plt.figure(1)
|
|
||||||
plt.savefig("../latex/images/problem8_a.pdf", bbox_inches="tight")
|
|
||||||
plt.figure(2)
|
|
||||||
plt.savefig("../latex/images/problem8_b.pdf", bbox_inches="tight")
|
|
||||||
plt.figure(3)
|
|
||||||
plt.savefig("../latex/images/problem8_c.pdf", bbox_inches="tight")
|
|
||||||
|
|
||||||
if __name__ == "__main__":
|
|
||||||
main()
|
|
||||||
0
src/problem2.cpp
Normal file
0
src/problem2.cpp
Normal file
162
src/simpleFile.cpp
Normal file
162
src/simpleFile.cpp
Normal file
@ -0,0 +1,162 @@
|
|||||||
|
#include <armadillo>
|
||||||
|
#include <cmath>
|
||||||
|
#include <ctime>
|
||||||
|
#include <fstream>
|
||||||
|
#include <iomanip>
|
||||||
|
#include <ios>
|
||||||
|
#include <string>
|
||||||
|
|
||||||
|
#define TIMING_ITERATIONS 5
|
||||||
|
|
||||||
|
arma::vec* general_algorithm(
|
||||||
|
arma::vec* sub_diag,
|
||||||
|
arma::vec* main_diag,
|
||||||
|
arma::vec* sup_diag,
|
||||||
|
arma::vec* g_vec
|
||||||
|
)
|
||||||
|
{
|
||||||
|
int n = g_vec->n_elem;
|
||||||
|
double d;
|
||||||
|
|
||||||
|
for (int i = 1; i < n; i++) {
|
||||||
|
d = (*sub_diag)(i-1) / (*main_diag)(i-1);
|
||||||
|
(*main_diag)(i) -= d*(*sup_diag)(i-1);
|
||||||
|
(*g_vec)(i) -= d*(*g_vec)(i-1);
|
||||||
|
}
|
||||||
|
|
||||||
|
(*g_vec)(n-1) /= (*main_diag)(n-1);
|
||||||
|
|
||||||
|
for (int i = n-2; i >= 0; i--) {
|
||||||
|
(*g_vec)(i) = ((*g_vec)(i) - (*sup_diag)(i) * (*g_vec)(i+1)) / (*main_diag)(i);
|
||||||
|
}
|
||||||
|
return g_vec;
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
arma::vec* special_algorithm(
|
||||||
|
double sub_sig,
|
||||||
|
double main_sig,
|
||||||
|
double sup_sig,
|
||||||
|
arma::vec* g_vec
|
||||||
|
)
|
||||||
|
{
|
||||||
|
int n = g_vec->n_elem;
|
||||||
|
arma::vec diag = arma::vec(n);
|
||||||
|
|
||||||
|
for (int i = 1; i < n; i++) {
|
||||||
|
// Calculate values for main diagonal based on indices
|
||||||
|
diag(i-1) = (double)(i+1) / i;
|
||||||
|
(*g_vec)(i) += (*g_vec)(i-1) / diag(i-1);
|
||||||
|
}
|
||||||
|
// The last element in main diagonal has value (i+1)/i = (n+1)/n
|
||||||
|
(*g_vec)(n-1) /= (double)(n+1) / (n);
|
||||||
|
|
||||||
|
for (int i = n-2; i >= 0; i--) {
|
||||||
|
(*g_vec)(i) = ((*g_vec)(i) + (*g_vec)(i+1))/ diag(i);
|
||||||
|
}
|
||||||
|
|
||||||
|
return g_vec;
|
||||||
|
}
|
||||||
|
|
||||||
|
void error(
|
||||||
|
std::string filename,
|
||||||
|
arma::vec* x_vec,
|
||||||
|
arma::vec* v_vec,
|
||||||
|
arma::vec* a_vec
|
||||||
|
)
|
||||||
|
{
|
||||||
|
std::ofstream ofile;
|
||||||
|
ofile.open(filename);
|
||||||
|
|
||||||
|
if (!ofile.is_open()) {
|
||||||
|
exit(1);
|
||||||
|
}
|
||||||
|
|
||||||
|
for (int i=0; i < a_vec->n_elem; i++) {
|
||||||
|
double sub = (*a_vec)(i) - (*v_vec)(i);
|
||||||
|
ofile << std::setprecision(8) << std::scientific << (*x_vec)(i)
|
||||||
|
<< std::setprecision(8) << std::scientific << std::log10(std::abs(sub))
|
||||||
|
<< std::setprecision(8) << std::scientific << std::log10(std::abs(sub/(*a_vec)(i)))
|
||||||
|
<< std::endl;
|
||||||
|
}
|
||||||
|
|
||||||
|
ofile.close();
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
double f(double x) {
|
||||||
|
return 100*std::exp(-10*x);
|
||||||
|
}
|
||||||
|
|
||||||
|
void build_array(
|
||||||
|
int n_steps,
|
||||||
|
arma::vec* sub_diag,
|
||||||
|
arma::vec* main_diag,
|
||||||
|
arma::vec* sup_diag,
|
||||||
|
arma::vec* g_vec
|
||||||
|
)
|
||||||
|
{
|
||||||
|
sub_diag->resize(n_steps-2);
|
||||||
|
main_diag->resize(n_steps-1);
|
||||||
|
sup_diag->resize(n_steps-2);
|
||||||
|
|
||||||
|
sub_diag->fill(-1);
|
||||||
|
main_diag->fill(2);
|
||||||
|
sup_diag->fill(-1);
|
||||||
|
|
||||||
|
g_vec->resize(n_steps-1);
|
||||||
|
|
||||||
|
double step_size = 1./ (double) n_steps;
|
||||||
|
for (int i=0; i < n_steps-1; i++) {
|
||||||
|
(*g_vec)(i) = f((i+1)*step_size);
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
void timing() {
|
||||||
|
arma::vec sub_diag, main_diag, sup_diag, g_vec;
|
||||||
|
int n_steps;
|
||||||
|
|
||||||
|
std::ofstream ofile;
|
||||||
|
ofile.open("timing.txt");
|
||||||
|
|
||||||
|
// Timing
|
||||||
|
for (int i=1; i <= 8; i++) {
|
||||||
|
n_steps = std::pow(10, i);
|
||||||
|
clock_t g_1, g_2, s_1, s_2;
|
||||||
|
double g_res = 0, s_res = 0;
|
||||||
|
|
||||||
|
for (int j=0; j < TIMING_ITERATIONS; j++) {
|
||||||
|
build_array(n_steps, &sub_diag, &main_diag, &sup_diag, &g_vec);
|
||||||
|
|
||||||
|
g_1 = clock();
|
||||||
|
|
||||||
|
general_algorithm(&sub_diag, &main_diag, &sup_diag, &g_vec);
|
||||||
|
|
||||||
|
g_2 = clock();
|
||||||
|
|
||||||
|
g_res += (double) (g_2 - g_1) / CLOCKS_PER_SEC;
|
||||||
|
build_array(n_steps, &sub_diag, &main_diag, &sup_diag, &g_vec);
|
||||||
|
|
||||||
|
s_1 = clock();
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||||||
|
|
||||||
|
special_algorithm(-1., 2., -1., &g_vec);
|
||||||
|
|
||||||
|
s_2 = clock();
|
||||||
|
|
||||||
|
s_res += (double) (s_2 - s_1) / CLOCKS_PER_SEC;
|
||||||
|
|
||||||
|
}
|
||||||
|
ofile
|
||||||
|
<< n_steps << ","
|
||||||
|
<< g_res / (double) TIMING_ITERATIONS << ","
|
||||||
|
<< s_res / (double) TIMING_ITERATIONS << std::endl;
|
||||||
|
}
|
||||||
|
|
||||||
|
ofile.close();
|
||||||
|
}
|
||||||
|
|
||||||
|
int main()
|
||||||
|
{
|
||||||
|
timing();
|
||||||
|
}
|
||||||
@ -1,52 +0,0 @@
|
|||||||
#include "funcs.hpp"
|
|
||||||
#include "specialAlgorithm.hpp"
|
|
||||||
|
|
||||||
arma::vec& special_algorithm(
|
|
||||||
double sub_sig,
|
|
||||||
double main_sig,
|
|
||||||
double sup_sig,
|
|
||||||
arma::vec& g_vec
|
|
||||||
)
|
|
||||||
{
|
|
||||||
int n = g_vec.n_elem;
|
|
||||||
arma::vec diag = arma::vec(n);
|
|
||||||
|
|
||||||
for (int i = 1; i < n; i++) {
|
|
||||||
// Calculate values for main diagonal based on indices
|
|
||||||
diag(i-1) = (double)(i+1) / i;
|
|
||||||
g_vec(i) += g_vec(i-1) / diag(i-1);
|
|
||||||
}
|
|
||||||
// The last element in main diagonal has value (i+1)/i = (n+1)/n
|
|
||||||
g_vec(n-1) /= (double)(n+1) / (n);
|
|
||||||
|
|
||||||
for (int i = n-2; i >= 0; i--) {
|
|
||||||
g_vec(i) = (g_vec(i) + g_vec(i+1))/ diag(i);
|
|
||||||
}
|
|
||||||
|
|
||||||
return g_vec;
|
|
||||||
}
|
|
||||||
|
|
||||||
void special_algorithm_main()
|
|
||||||
{
|
|
||||||
arma::vec g_vec, v_vec;
|
|
||||||
std::ofstream ofile;
|
|
||||||
int steps;
|
|
||||||
double sub_sig, main_sig, sup_sig, step_size;
|
|
||||||
|
|
||||||
for (int i = 0; i < N_STEPS_EXP; i++) {
|
|
||||||
steps = std::pow(10, i+1);
|
|
||||||
step_size = 1./(double) steps;
|
|
||||||
build_g_vec(steps, g_vec);
|
|
||||||
|
|
||||||
v_vec = special_algorithm(sub_sig, main_sig, sup_sig, g_vec);
|
|
||||||
|
|
||||||
ofile.open("output/special/out_" + std::to_string(steps) + ".txt");
|
|
||||||
|
|
||||||
for (int j=0; j < v_vec.n_elem; j++) {
|
|
||||||
ofile << std::setprecision(PRECISION) << std::scientific << step_size*(j+1) << ","
|
|
||||||
<< std::setprecision(PRECISION) << std::scientific << v_vec(j) << std::endl;
|
|
||||||
}
|
|
||||||
ofile.close();
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
@ -1,16 +0,0 @@
|
|||||||
#ifndef __SPECIAL_ALG__
|
|
||||||
#define __SPECIAL_ALG__
|
|
||||||
|
|
||||||
#include <armadillo>
|
|
||||||
#include <iomanip>
|
|
||||||
|
|
||||||
arma::vec& special_algorithm(
|
|
||||||
double sub_sig,
|
|
||||||
double main_sig,
|
|
||||||
double sup_sig,
|
|
||||||
arma::vec& g_vec
|
|
||||||
);
|
|
||||||
|
|
||||||
void special_algorithm_main();
|
|
||||||
|
|
||||||
#endif
|
|
||||||
@ -1,22 +0,0 @@
|
|||||||
import matplotlib.pyplot as plt
|
|
||||||
|
|
||||||
def main():
|
|
||||||
x = []
|
|
||||||
gen_alg = []
|
|
||||||
spec_alg = []
|
|
||||||
with open(f"output/timing.txt", "r") as f:
|
|
||||||
lines = f.readlines()
|
|
||||||
for line in lines:
|
|
||||||
x_i, gen_i, spec_i = line.strip().split(",")
|
|
||||||
x.append(float(x_i))
|
|
||||||
gen_alg.append(float(gen_i))
|
|
||||||
spec_alg.append(float(spec_i))
|
|
||||||
|
|
||||||
plt.plot(x, gen_alg, label=f"General algorithm")
|
|
||||||
plt.plot(x, spec_alg, label=f"Special algorithm")
|
|
||||||
|
|
||||||
plt.legend()
|
|
||||||
plt.savefig("../latex/images/problem10.pdf")
|
|
||||||
|
|
||||||
if __name__ == "__main__":
|
|
||||||
main()
|
|
||||||
Loading…
Reference in New Issue
Block a user