25.4: Example
- Page ID
- 54409
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)This section provides an example program that plots a simple function.
\[ y = \sin(x) \cdot \left( \frac{1 - \cos(x)}{3.0} \right) \nonumber \]
The program, data file, and final output are presented for reference.
Plot Program
The following is an example program that generates points, opens a plot file, write the header, data points, and footer.
program plotExample
implicit none
real, dimension(200) :: x, y
integer :: i, opnstat
! Generate x and y points
do i = 1, 200
x(i) = i * 0.05
y(i) = sin(x(i)) * (1-cos(x(i)/3.0))
end do
! Output data to a file
open (12, file="data.plt", status="replace", &
action="write", position="rewind", &
iostat=opnstat)
if (opnstat > 0) stop "error opening plot file."
! Write header
write (12, '(a)') "# Example Plot File"
write (12, '(a)') "set title ""Example Plot Function"" "
write (12,'(a,a)') "plot ""-"" notitle with dots ",
"linewidth 2 linecolor 2"
! Write points to file.
do i=1,100
write (12,*) x(i), y(i)
end do
! Write footer and close file
write (12, '(a)') "end"
write (12, '(a)') "pause -1"
close(12)
end program plotExample
The data file name can be changed or read from the user.
Plot File
The output file from this program appears as follows:
# Example Plot File
set title "Example Plot Function"
plot "-" notitle with dots linewidth 2 linecolor 2
5.0000001E-02 6.9413913E-06
0.1000000 5.5457884E-05
0.1500000 1.8675877E-04
0.2000000 4.4132397E-04
0.2500000 8.5854460E-04
[many points not displayed due to space considerations]
4.900000 -1.043852
4.950000 -1.048801
5.000000 -1.050716
end
pause -1
The output file can be edited with a standard text editor. This will allow checking the data file for possible errors if it does not display correctly.
Plot Output
The plot output is as follows:
On Windows machines, the plot can be printed by right clicking on the blue bar (on top). This will display a menu, with “Print” as one of the options.