196 lines
4.2 KiB
Matlab
196 lines
4.2 KiB
Matlab
%%%% ECE-210-B HW 3 - Plotting
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% James Ryan, 02/14/24
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% preamble
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close all; clear; clc;
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%% Two Dimensions
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% (1)
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x = linspace(0, 2*pi, 50);
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f = sin(x);
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figure;
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plot(x, f, "g");
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xlim([0 2*pi]); % plot only within x's range
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xticks([0:pi/2:2*pi]);
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xticklabels({'0','\pi/2','\pi','3\pi/2','2\pi'})
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xlabel("x");
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ylabel("sin(x)");
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title('Plot of sin(x) over 50 evenly spaced points between [0, 2\pi]');
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% (2)
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x; % 50 evenly spaced pts between [0, 2pi]
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g = cos(2.*x);
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figure;
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hold on;
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plot(x, f, "g");
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plot(x, g, "b");
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hold off;
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xlim([0 2*pi]); % plot only within x's range
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xticks([0:pi/2:2*pi]);
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xticklabels({'0','\pi/2','\pi','3\pi/2','2\pi'})
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xlabel("x");
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ylabel("y");
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legend( 'y = sin(x)', ...
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'y = cos(2x)');
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% <-.02> (style) one thing about tabs: they don't always line
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% up the same way on other people's machines. this indentation
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% looks... strange to me, with my 8-space tabstops.
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title('knock knock! whose there? sin! sine who? $\pm\sqrt{\frac{1 + cos2\theta}{2}}$', "interpreter", "latex");
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% <+.02> nice.
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% (3)
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figure;
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x; % 50 evenly spaced pts between [0, 2pi]
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% top plot - f = sin(x)
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subplot(2,1,1);
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stem(x, f, "r*");
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grid on
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xlim([0 2*pi]);
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xticks([0:pi/2:2*pi]);
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xticklabels({'0','\pi/2','\pi','3\pi/2','2\pi'})
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xlabel("t [s]"); % we're pretending its time now :)
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ylabel("Position [d]");
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title('Position of a controlled laser pointer, relative to origin location');
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subtitle('Sampled 50 times over 2\pi seconds.');
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% <+.01> the theme here really gets me.
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% bottom plot - g = cos(2x)
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% changing cos(2x)'s amplitude; computing amplitude ratio in d
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rand_amp = 100 * rand;
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g = rand_amp .* g;
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amplitude_ratio_db = 20.*log10(rand_amp);
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subplot(2,1,2);
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stem(x, g, "color", "#D95319", "Marker", "+", "MarkerEdgeColor", "#D95319", "MarkerFaceColor", "#D95319");
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% (style) these are very long lines...
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grid on
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xlim([0 2*pi]);
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xticks([0:pi/2:2*pi]);
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xticklabels({'0','\pi/2','\pi','3\pi/2','2\pi'})
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yticks(linspace(-rand_amp, rand_amp, 5));
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% usually ticks are nicely readable numbers for, well,
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% readability.
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xlabel("t [s]");
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ylabel("Position [d]");
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title(sprintf('Pet cats vertical position while seeking laser pointer. \n Position Ratio (vs sin) [dB]: %d' ...
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,amplitude_ratio_db));
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% (interesting place for that comma)
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subtitle('Sampled 50 times over 2\pi seconds.');
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% (4)
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pointer = imread("./pointer.jpg");
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% <-.05> image was not submitted! i went and found one...
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%{
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returns a 720x1280x3 matrix, corresponding to
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720 rows
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1280 columns
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3 color channels per (row,col) pair
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to form a complete color image, in matrix form.
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Each entry in the matrix is stored as uint8, or
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an 8-bit integer, implying colors are specified as
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hex codes (eg #RRGGBB - specify the Red, Green, and
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Blue values in HEX, 8 bits per channel, 3 channels).
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%}
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% Invert color channels
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new_pointer = 255 - pointer;
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figure;
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imshow(pointer);
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figure;
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imshow(new_pointer);
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%% Three Dimensions
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% (1)
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x = 0:.01:1;
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y = x;
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z = exp(-x.^2 - y.^2);
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figure;
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% "Create this plot
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% three times
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% in three different subplots
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% using plot3..., scatter3, surf, *and* mesh (4 tools?)"
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% I'm making 4 plots, because you said "and", meaning all the tools.
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% that is indeed what i meant for you to do. good catch.
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% plot3
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subplot(2,2,1);
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plot3(x,y,z);
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xlabel("x");
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ylabel("y");
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zlabel("z");
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title('z = exp(-x^2 - y^2) (PLOT3)');
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legend('z = exp(-x^2 - y^2)');
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daspect([1 1 1]);
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view([-2 2 1]);
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grid on;
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% scatter3
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subplot(2,2,2);
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scatter3(x,y,z);
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xlabel("x");
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ylabel("y");
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zlabel("z");
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title('z = exp(-x^2 - y^2) (SCATTER)');
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legend('z = exp(-x^2 - y^2)');
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daspect([1 1 1]);
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view([-2 2 1]);
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grid on;
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% <-.00> i was not totally clear here, so i'll let this slide,
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% but i meant plot the surface itself using `scatter` and
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% `plot3`.
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% surf
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[X, Y] = meshgrid(x);
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Z = exp(-X.^2 - Y.^2);
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subplot(2,2,3);
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surf(X,Y,Z);
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xlabel("x");
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ylabel("y");
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zlabel("z");
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title('z = exp(-x^2 - y^2) (SURF)');
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legend('z = exp(-x^2 - y^2)');
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grid on;
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view([-2 5 1.3]);
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% mesh
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subplot(2,2,4);
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mesh(X,Y,Z);
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xlabel("x");
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ylabel("y");
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zlabel("z");
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title('z = exp(-x^2 - y^2) (MESH)');
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legend('z = exp(-x^2 - y^2)');
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grid on;
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view([-2 5 1.3]);
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% (2)
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t = 0:0.01:1;
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x = t.*cos(27.*t);
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y = t.*sin(27.*t);
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z = t;
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figure;
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plot3(x,y,t);
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xlabel("x");
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ylabel("y");
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zlabel("z");
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title('Wheeee!');
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grid on;
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daspect([1 1 1]);
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view([90 90 20]);
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