* Example of starting octave in WSL2, and loading in two columns of data from a text file
And then plotting them with three different graphics environments (gnuplot is prob the most robust)
> octave --no-gui
% %%%%%%%%%%%%%%%%%%%%%%%%
graphics_toolkit gnuplot
fp = fopen('datafile.txt', 'r');
greg = fscanf(fp, '%f %f', [2 Inf]);
fclose(fp);
tvec = greg(1, 1:end);
yvec = greg(2, 1:end);
plot(tvec, yvec)
% %%%%%%%%%%%%%%%%%%%%%%%%
% %%%%%%%%%%%%%%%%%%%%%%%%
graphics_toolkit qt
fp = fopen('datafile.txt', 'r');
greg = fscanf(fp, '%f %f', [2 Inf]);
fclose(fp);
tvec = greg(1, 1:end);
yvec = greg(2, 1:end);
plot(tvec, yvec)
% %%%%%%%%%%%%%%%%%%%%%%%%
% %%%%%%%%%%%%%%%%%%%%%%%%
graphics_toolkit fltk
fp = fopen('datafile.txt', 'r');
greg = fscanf(fp, '%f %f', [2 Inf]);
fclose(fp);
tvec = greg(1, 1:end);
yvec = greg(2, 1:end);
plot(tvec, yvec)
% %%%%%%%%%%%%%%%%%%%%%%%%
* Interactive gnuplot commands
(you can get these commands by starting gnuplot from bash - then type "show bind")
2x<B1> print coordinates to clipboard using `clipboardformat`
(see keys '3', '4')
<B2> annotate the graph using `mouseformat` (see keys '1', '2')
or draw labels if `set mouse labels is on`
<Ctrl-B2> remove label close to pointer if `set mouse labels` is on
<B3> mark zoom region (only for 2d-plots and maps).
<B1-Motion> change view (rotation). Use <ctrl> to rotate the axes only.
<B2-Motion> change view (scaling). Use <ctrl> to scale the axes only.
<Shift-B2-Motion> vertical motion -- change xyplane
Space raise gnuplot console window
q * close this plot window
a `builtin-autoscale` (set autoscale keepfix; replot)
b `builtin-toggle-border`
e `builtin-replot`
g `builtin-toggle-grid`
h `builtin-help`
l `builtin-toggle-log` y logscale for plots, z and cb for splots
L `builtin-nearest-log` toggle logscale of axis nearest cursor
m `builtin-toggle-mouse`
r `builtin-toggle-ruler`
1 `builtin-decrement-mousemode`
2 `builtin-increment-mousemode`
3 `builtin-decrement-clipboardmode`
4 `builtin-increment-clipboardmode`
5 `builtin-toggle-polardistance`
6 `builtin-toggle-verbose`
7 `builtin-toggle-ratio`
n `builtin-zoom-next` go to next zoom in the zoom stack
p `builtin-zoom-previous` go to previous zoom in the zoom stack
u `builtin-unzoom`
Right `builtin-rotate-right` only for splots; <shift> increases amount
Up `builtin-rotate-up` only for splots; <shift> increases amount
Left `builtin-rotate-left` only for splots; <shift> increases amount
Down `builtin-rotate-down` only for splots; <shift> increases amount
Escape `builtin-cancel-zoom` cancel zoom region
* indicates this key is active from all plot windows
* Plot simple graph
graphics_toolkit gnuplot
xvec = (0:400)*6*pi/400;
yvec = sin(xvec);
plot(xvec, yvec);
* Very important
available_graphics_toolkits
graphics_toolkit gnuplot
fs = 2e6;
wc = pi / 4 * fs;
df = fs / 2 / 1000;
f = (0:1000) * df;
s = i * 2*pi*f;
T = 1/fs;
z = exp(i*2*pi*f*T);
Ha = 1./(1+s./wc).^2;
plot(f, Ha)
figure --> bring up a figure window
' --> transpose operator
; --> end of a row in a matrix
start:end or start:step:end
>> a = [1:1:10]
a =
1 2 3 4 5 6 7 8 9 10
***********************************
octave --gui
https://www.mathworks.com/help/matlab/getting-started-with-matlab.html
* complex numbers --> i or j
* ; --> suppress printing answer
* a = [1 2 3; 4 5 6; 7 8 9]
* format long
format short
* b = zeros(5, 1)
* A(4, 2) --> row=4 col=2
rows begin at 1
cols begin at 1
strangely, you can refer to this as A(8)
The data in an array is stored in terms of columns serially
* A(1:3, 2) --> column vector taken from col=2
* A = 0
A(10, 6) = 1.5
(this add 9 rows and 5 cols)
* A(3, :)
B = 0:10:100 --> [0 10 20 30 40 50 60 70 80 90 100]
B = 0:10 --> [0 1 2 3 4 5 6 7 8 9 10]
* D = rand(3, 5, 2)
D(:,:,1)
D(:,:,2)
* save myfile.mat
* load myfile.mat
* (begin example myfile.mat)
# Created by Greg Warwar
# name: greg
# type: matrix
# ndims: 2
3 2
1
2
3
4
5
6
# name: shan
# type: matrix
# rows: 3
# columns: 2
1 4
2 5
3 6
* (end example myfile.mat)