有哪些用 MATLAB 绘制的绝美图案？

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有哪些用 MATLAB 绘制的绝美图案？

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14 个回答

谈不上绝美图案，只是一些绘图案例；

先睹为快

二维曲线图
二维散点图
二维渐变色图
二维条形图
二维填充图
多 Y 轴图
二维场图
带箭头曲线图
三维曲线图
三维散点图
伪彩图
裁剪伪彩图
等高线图
等高线填充图
矢量场图
伪彩图+投影图
条形分布图
热图
分子模型图
分形图
曲线斜线填充
曲面贴图
自定义颜色图
gif 动态图
方程曲线图
极坐标图
不相交随机圆
BP 神经网络图
小圆构成的圆环
棋盘格

二维曲线

二维曲线算是最最常见的一种曲线了，它能反应两个变量的因果关系；

clear;clc;close all;
x = linspace(1, 200, 100);
y1 = log(x) + 1;
y2 = log(x) + 2;
figure;
plot(x, y1);
hold on
plot(x, y2, 'LineWidth', 2);
hold off
legend('y1', 'y2');

调整线的粗细，给人感觉就不一样；

或者说这个颜色可能你觉得不好看，查阅帮助文档里给的的标准颜色也都不喜欢；

没关系，我整理了 28 种个人觉得比较好看的颜色，自行做一下颜色搭配，一般够用了；

figure;
plot(x, y1, 'LineWidth', 2, 'Color', [0.21, 0.21, 0.67]);
hold on
plot(x, y2, 'LineWidth', 2, 'Color', [0.99, 0.49, 0.00]);
hold off
legend('y1', 'y2');

二维散点图

常用来比较理论数据和实验数据的趋势关系；

figure;
y3 = y1 + rand(1, 100) - 0.5;
plot(x, y1, 'LineWidth', 2, 'Color', [0.21, 0.21, 0.67]);
hold on
% 设置数据点的形状、数据点的填充颜色、数据点的轮廓颜色
plot(x, y3, 'o', 'LineWidth', 2, 'Color', [0.46, 0.63, 0.90], 'MarkerFaceColor', [0.35, 0.90, 0.89], 'MarkerEdgeColor', [0.18, 0.62, 0.17]);
hold off

二维渐变色图

用不同的颜色、数据点大小表征不同数值，更加直观；

更详细的案例分析：

% 先自己做一个 colormap
c_map =  [0.00, 0.36, 0.67
          0.68, 0.42, 0.89
          0.44, 0.62, 0.98
          0.10, 0.67, 0.59
          0.99, 0.57, 0.59
          0.28, 0.55, 0.86
          0.96, 0.62, 0.24
          0.30, 0.90, 0.56
          0.12, 0.46, 0.71
          0.46, 0.63, 0.90
          0.96, 0.37, 0.40
          0.14, 0.76, 0.71
          0.99, 0.50, 0.02
          0.00, 0.57, 0.76
          0.35, 0.90, 0.89
          0.17, 0.62, 0.47
          0.21, 0.21, 0.67
          0.99, 0.49, 0.00
          0.98, 0.74, 0.44
          0.97, 0.60, 0.58
          0.18, 0.62, 0.17
          0.68, 0.87, 0.53
          0.12, 0.46, 0.70
          0.65, 0.79, 0.89
          0.95, 0.99, 0.69
          0.74, 0.92, 0.68
          0.37, 0.81, 0.72
          0.01, 0.72, 0.77];
scatter(x, y3, x, x, 'filled');
colormap(c_map);

figure;
fill([x, NaN], [y2, NaN], [x, NaN], 'EdgeColor', 'interp', 'LineWidth', 2);

条形图

正常条形图没啥好说的，这里演示绘制带有误差线的柱状图：

figure;
m = 5;
n = 3;
x = 1:m;
y = rand(m, n) + 2;
% 误差限
neg = rand(m, n);
pos = rand(m, n);
% 绘制柱状图
h = bar(x, y);
% 设置三个系列颜色
h(1, 1).FaceColor = [0.00, 0.36, 0.67];
h(1, 2).FaceColor = [0.68, 0.42, 0.89];
h(1, 3).FaceColor = [0.44, 0.62, 0.98];
% 单独设置第二个系列第二个柱子颜色
h(1, 2).FaceColor = 'flat';
h(1, 2).CData(2,:) = [0.21, 0.21, 0.67]; 
% 获取误差线 x 值
xx = zeros(m, n);
for i = 1 : n
    xx(:, i) = h(1, i).XEndPoints'; 
% 绘制误差线
hold on
errorbar(xx, y, neg, pos, 'LineStyle', 'none', 'Color', 'm', 'LineWidth', 1.5);
hold off
% 绘制图例
legend({'A1', 'A2', 'A3'});
% 设置 x 轴标签
set(gca, 'XTickLabel', {'label1', 'label2', 'label3', 'label4', 'label5'});

填充图

x = 0.4:0.1:2*pi;
y1 = sin(2*x);
y2 = sin(x);
% 确定 y1 和 y2 的上下边界
maxY = max([y1; y2]);
minY = min([y1; y2]);
% 确定填充多边形，按照顺时针方向来确定点
% fliplr 实现左右翻转
xFill = [x, fliplr(x)];
yFill = [maxY, fliplr(minY)];
figure
fill(xFill, yFill, [0.21, 0.21, 0.67]);
hold on
% 绘制轮廓线
plot(x, y1, 'k', 'LineWidth', 2)
plot(x, y2, 'k', 'LineWidth', 2)
hold off

% 函数交叉区域填充
figure;
% 这是三个方程
g1 = @(x,y) 1 - x.^2.*y/20;
g2 = @(x, y) 1 - (x+y-5).^2/30 - (x-y-12).^2/120;
g3 = @(x, y) 1 - 80./(x.^2 + 8*y + 5);
% 把他们的图像画出来
h1 = fimplicit(g1, [0, 10], 'LineWidth', 2);
hold on
h2 = fimplicit(g2, [0, 10], 'LineWidth', 2);
h3 = fimplicit(g3, [0, 10], 'LineWidth', 2);
legend('g1', 'g2', 'g3');
% 问题来了，这个 y 值怎么确定
x1 = h1.XData;
y1 = h1.YData;
x2 = h2.XData;
y2 = h2.YData;
x3 = h3.XData;
y3 = h3.YData;
% 发现 x1, x2 是从大到小的，逆序搞一下
x1 = fliplr(x1);
x2 = fliplr(x2);
y1 = fliplr(y1);
y2 = fliplr(y2);
% 接下来，确定相交区域，主要看这三个关键点：g1-g2, g1-g3, g2-g3
% 数据长度不一样，难搞了，借助【数据提示】功能吧
pt1 = [3.11069, 2.06667];
pt2 = [8.53623, 0.266667];
pt3 = [7.7847, 1.8];
% 确定三个范围
idx1 = find(x1 >= pt1(1) & x1 < pt2(1));
idx2 = find(x2 >= pt1(1) & x2 < pt3(1));
idx3 = find(x3 >= pt3(1) & x3 < pt2(1));
x1 = x1(idx1);
x2 = x2(idx2);
x3 = x3(idx3);
y1 = y1(idx1);
y2 = y2(idx2);
y3 = y3(idx3);
% 一定要是一个闭环
xFill = [x1, fliplr(x3), fliplr(x2)];
yFill = [y1, fliplr(y3), fliplr(y2)];
fill(xFill, yFill, [0.21, 0.21, 0.67]);
hold off

多 Y 轴图

figure;
load('accidents.mat','hwydata')
ind = 1:51;
drivers = hwydata(:,5);
yyaxis left
scatter(ind, drivers, 'LineWidth', 2);
title('Highway Data');
xlabel('States');
ylabel('Licensed Drivers (thousands)');
pop = hwydata(:,7);
yyaxis right
scatter(ind, pop, 'LineWidth', 2);
ylabel('Vehicle Miles Traveled (millions)');

figure;
x = linspace(0,10);
y1 = 2*sin(3*x);
y2 = sin(3*x).*exp(0.5*x);
%% 三个纵坐标演示，更多纵坐标可以按照此方法类推
y3 = 10*cos(3*x);
% 控制 aies 的大小和位置，注意是相对于figure的，范围为[0, 1]
% 三条线绘制到一起，注意数据都标准化到 y1 范围
maxY1 = max(y1);
maxY2 = max(y2);
maxY3 = max(y3);
minY1 = min(y1);
minY2 = min(y2);
minY3 = min(y3);
newY2 = (y2 - minY2)/(maxY2 - minY2);   % 归一化
newY2 = newY2*(maxY1 - minY1) + minY1;  % 反归一化
newY3 = (y3 - minY3)/(maxY3 - minY3);
newY3 = newY3*(maxY1 - minY1) + minY1;
axes('position', [0.1 0.1 0.5 0.5]);   
plot(x, y1, 'k', x, newY2, 'r', x, newY3, 'ob--')
ylabel('line1');
% 绘制另外两个空的坐标轴
h2 = axes('position', [0.65 0.1 0.005 0.5]); 
% 重复绘制，曲线颜色用白色，和figure背景色一致，看不出来即可
plot(x, y2, 'w')
% 颜色，位置，曲线标签
set(h2, 'ycolor', 'r', 'yaxislocation', 'right', 'xtick', [])
% 不知道为啥2018B版本边界显示不清楚，所以画一条线
hold on
limX2 = get(h2, 'Xlim');
limY2 = get(h2, 'Ylim');
plot([limX2(2), limX2(2)], limY2, 'r');
hold off
% 取消边框
box off
ylabel('line2');
h3 = axes('position', [0.75 0.1 0.005 0.5]); 
plot(x, y3, 'w')
set(h3, 'ycolor', 'b', 'yaxislocation', 'right', 'xtick', [])
hold on
limX3 = get(h3, 'Xlim');
limY3 = get(h3, 'Ylim');
plot([limX3(2), limX3(2)], limY3, 'b');
hold off
box off
ylabel('line3');
% 取消坐标轴的颜色，和figure统一
% set(h1, 'color','none')
% set(h2, 'color','none')
% set(h3, 'color','none')
% figure背景设置成白色
set(gcf,'color','white');

二维场图

% 直接把 streamline 函数的帮助文档 demo 拷贝过来 
[x, y] = meshgrid(0:0.1:1, 0:0.1:1);
u = x;
v = -y;
startx = 0.1:0.1:0.9;
starty = ones(size(startx));
% 需要获取所有流线的属性
figure;
quiver(x, y, u, v);
streamline(x, y, u, v, startx, starty);

带箭头曲线

% 直接把 streamline 函数的帮助文档 demo 拷贝过来 
figure;
[x, y] = meshgrid(0:0.1:1, 0:0.1:1);
u = x;
v = -y;
startx = 0.1:0.1:0.9;
starty = ones(size(startx));
% 需要获取所有流线的属性
lines = streamline(x, y, u, v, startx, starty);
% 下面开始画箭头，涉及到坐标的转换
% 获取 Axes 位置
posAxes = get(gca, 'Position');
posX = posAxes(1);
posY = posAxes(2);
width = posAxes(3);
height = posAxes(4);
% 获取 Axes 范围
limX = get(gca, 'Xlim');
limY = get(gca, 'Ylim');
minX = limX(1);
maxX = limX(2);
minY = limY(1);
maxY = limY(2);
% 遍历，逐条流线加箭头
for i = 1 : length(lines)
    % 获取每条流线的数据
    xData = lines(i).XData;
    yData = lines(i).YData;
    % 这里取的是最后两个点，一定要是相邻的两个点用来确定箭头方向
    x0 = xData(end-1 : end);
    y0 = yData(end-1 : end);
    % 转换坐标到相对于figure的坐标
    xNew = posX + (x0 - minX) / (maxX - minX) * width;
    yNew = posY + (y0 - minY) / (maxY - minY) * height;
    % 画箭头
    hold on
    annotation('arrow', xNew, yNew, 'color', 'b');
hold off
title('带箭头的流线图');

三维曲线图

figure;
t = 0:pi/20:10*pi;
xt = sin(t);
yt = cos(t);
plot3(xt, yt, t, '-o', 'Color', 'b', 'MarkerSize', 10, 'MarkerFaceColor', '#D9FFFF');

figure;
x = -20:10:20;
y = 0:100;
% 随便生成的 5 组数据，也就是目标图上的 5 条曲线数据
z = zeros(5, 101);
z(1, 1:10:end) = linspace(1, 10, 11);
z(2, 1:10:end) = linspace(1, 20, 11);
z(3, 1:10:end) = linspace(1, 5, 11);
z(4, 5:10:end) = linspace(1, 10, 10);
z(5, 80:2:end) = linspace(1, 5, 11);
for i = 1:5
    % x 方向每条曲线都是一个值，重复 y 的长度这么多次 
    xx = x(i)*ones(1, 101);
    % z 方向的值，每次取一条
    zz = z(i, :);
    % plot3 在 xyz 空间绘制曲线，保证 x y z 长度一致即可
    plot3(xx, y, zz, 'LineWidth', 2);
    hold on
hold off
legend('line1', 'line2', 'line3', 'line4', 'line5');

% 如果把渐变曲线和三维曲线结合起来
figure;
x = linspace(0, 2*pi, 50);
y = sin(x);
fill3([ones(size(x)), NaN], [x, NaN], [y, NaN], [x NaN], 'EdgeColor', 'interp', 'LineWidth', 2)
hold on
for i = 2 : 5
    if mod(i, 2) == 0
        y = sin(2*x);
        fill3([i * ones(size(x)), NaN], [x, NaN], [y, NaN], [x NaN], 'EdgeColor', 'interp', 'LineWidth', 2)
        y = sin(10*x);
        fill3([i * ones(size(x)), NaN], [x, NaN], [y, NaN], [x NaN], 'EdgeColor', 'interp', 'LineWidth', 2)
hold off

三维散点图

figure;
[X,Y,Z] = sphere(16);
x = [0.5*X(:); 0.75*X(:); X(:)];
y = [0.5*Y(:); 0.75*Y(:); Y(:)];
z = [0.5*Z(:); 0.75*Z(:); Z(:)];
S = repmat([70, 50, 20],numel(X), 1);
C = repmat([1, 2, 3], numel(X), 1);
s = S(:);
c = C(:);
h = scatter3(x, y, z, s, c);
h.MarkerFaceColor = [0 0.5 0.5];

x = linspace(1, 200, 100);
y1 = log(x) + 1;
y2 = log(x) + 2;
y3 = y1 + rand(1, 100) - 0.5;
figure;
scatter3(x, y2, y3, x, x, 'filled');
colormap(c_map);

三维伪彩图

[x, y, z] = peaks(30);
figure;
plot1 = subplot(1,2,1);
surf(x, y, z);
% 获取第一幅图的 colormap，默认为 parula
cMap = colormap;
plot2 = subplot(1,2,2);
surf(x, y, z);
% 下面设置的是第二幅图的颜色，默认是整个 figure 的
colormap(hot);
% 设置第一幅图颜色显示为 parula
set(plot1, 'Colormap', cMap);

% 一个坐标轴
figure;
h1 = surf(x, y, z);
freezeColors;
hold on
h2 = surf(x, y, z + 5);
hold off
colormap(hot);

裁剪伪彩图

figure;
n = 300;
[x, y, z] = peaks(n);
subplot(2, 2, [1,3])
surf(x, y, z);
shading interp
view(0, 90)
for i = 1:n
    for j = 1:n
        if x(i, j)^2 + 2 * y(i, j)^2 > 6 && 2 * x(i, j)^2 + y(i, j)^2 < 6
            z(i, j) = NaN;
subplot(2, 2, 2)
surf(x, y, z);
shading interp
view(0, 90)
subplot(2, 2, 4)
surf(x, y, z);
shading interp

等高线图

figure;
[X, Y, Z] = peaks;
subplot(2, 2, 1);
contour(X, Y, Z, 20, 'LineWidth', 2);
subplot(2, 2, 2);
contour(X, Y, Z, '--', 'LineWidth', 2)
subplot(2, 2, 3);
v = [1, 1];
contour(X, Y, Z, v, 'LineWidth', 2);
x = -2:0.2:2;
y = -2:0.2:3;
[X, Y] = meshgrid(x, y);
Z = X.*exp(-X.^2-Y.^2);
subplot(2, 2, 4);
contour(X, Y, Z, 'ShowText','on', 'LineWidth', 2);

figure('Position', [0, 0, 900, 400]);
subplot(1, 3, 1);
[X, Y, Z] = sphere(50);
contour3(X, Y, Z, 'LineWidth', 2);
[X, Y] = meshgrid(-2:0.25:2);
Z = X.*exp(-X.^2-Y.^2);
subplot(1, 3, 2);
contour3(X, Y, Z, [-0.2 -0.1 0.1 0.2], 'ShowText', 'on', 'LineWidth', 2)
[X, Y, Z] = peaks;
subplot(1, 3, 3);
contour3(X, Y, Z, [2 2], 'LineWidth', 2);

等高线填充图

figure;
subplot(2, 2, 1);
[X, Y, Z] = peaks(50);
contourf(X, Y, Z);
subplot(2, 2, 2);
contourf(X, Y, Z,'--');
% 限定范围
subplot(2, 2, 3);
contourf(X, Y, Z, [2 3], 'ShowText', 'on');
subplot(2, 2, 4);
contourf(X, Y, Z,[2 2]);

三维矢量场图

figure;
[X, Y, Z] = peaks(30);
% 矢量场，曲面法线
[U, V, W] = surfnorm(X, Y, Z);   
% 箭头长度、颜色
quiver3(X, Y, Z, U, V, W, 0.5, 'r');     
hold on
surf(X,Y,Z);  
xlim([-3, 3]);
ylim([-3, 3.2]);
shading interp
hold off
view(0, 90);

伪彩图+投影图

clear;clc;close all;
x = linspace(-3, 3, 30);
y = linspace(-4, 4, 40);
[X, Y] = meshgrid(x, y);
Z = peaks(X, Y);
Z(5:10, 15:20) = 0;
z1 = max(Z);
z2 = max(Z, [], 2);
figure;
subplot(3, 3, [1, 2]);
plot(x, z1, 'LineWidth', 2);
subplot(3, 3, [6, 9]);
plot(z2, y, 'LineWidth', 2);
subplot(3, 3, [4, 5, 7, 8]);
surf(x, y, Z);
xlim([-3, 3]);
ylim([-4, 4]);
view(0, 90);
shading interp

figure;
% 3*3 布局
tiledlayout(3, 3, 'TileSpacing', 'Compact');
% 占据 1*2，也就是 1 2
nexttile([1, 2]);
plot(x, z1, 'LineWidth', 2);
% 从第 6 个开始，占据 2*1，也就是 6 和 9
nexttile(6, [2, 1]);
plot(z2, y, 'LineWidth', 2);
% 从第 4 个开始，占据 2*2，也就是 4 5 7 8
nexttile(4, [2, 2]);
surf(x, y, Z);
xlim([-3, 3]);
ylim([-4, 4]);
view(0, 90);
shading interp

条形分布图

clear;clc;
x = linspace(-10, 10, 100);
y = gauss(100, 5) ; 
figure;
% 设置边缘颜色和宽度
bar(x, y, 'EdgeColor', 'none', 'BarWidth', 1);

热图

clear;clc;
z = rand(50);
z(z >= 0.0 & z < 0.6) = 0.5;
z(z >= 0.6 & z < 0.8) = 0.7;
z(z >= 0.8 & z <= 1) = 0.9;
for i = 1:30
    z(randi(50, 1, 1) : end, i) = nan;
for i = 31:50
    z(30 + randi(20, 1, 1) : end, i) = nan;
z(20:25, 40:45) = nan;
figure;
% ax = surf(z);
ax = pcolor(z);
view(0, 90);
ax.EdgeColor = [1 1 1];
axis off

figure;
for i = 1:50
    for j = 1:50
        if ~isnan(z(i, j))
            x = [i - 1, i, i, i - 1];
            y = [j - 1, j - 1, j, j];
            c1 = 'w';
            c2 = 'w';
            if z(i, j) >= 0.1
                c1 = 'black';
                c2 = [0.65, 0.78, 0.56];
                if z(i, j) >= 0.6
                    c2 = [0.98, 0.46, 0.23];
                    if z(i, j) >= 0.8
                        c2 = [0.99, 0.02, 0.02];
            patch(x, y, c2, 'EdgeColor', c1);
axis off

分子模型图

clear;clc;
% 球面的坐标信息，为了看起来平滑一点，给到 100
[x, y, z] = sphere(100);
% C 大小
C = 10; 
% H 大小
H = 5;
figure;
surf(C*x, C*y, C*z, 'FaceColor', 'red', 'EdgeColor', 'none')
hold on 
% 四个小球，都偏离一点位置，准确的位置需要计算，这里演示一个大概位置
surf(H*x, H*y, H*z + 10, 'FaceColor', 'blue', 'EdgeColor', 'none');
surf(H*x + 10, H*y, H*z - 3, 'FaceColor', 'blue', 'EdgeColor', 'none');
surf(H*x - 4, H*y - 10, H*z - 3, 'FaceColor', 'blue', 'EdgeColor', 'none');
surf(H*x - 4, H*y + 10, H*z - 3, 'FaceColor', 'blue', 'EdgeColor', 'none');
% 坐标轴设置
axis equal off
% 光源，看起来更有立体感
light
lighting gouraud

分形图

clear;clc;
n = 1000;
m = 1000;
f = @(z) z^8 - 1;
df = @(z) 8*z^7;
[X, Y] = meshgrid(linspace(-2, 2, n), linspace(-2, 2, m));
A = nan(n, m);
for i = 1:n
    for j = 1:m
        z0 = X(i, j) + 1i*Y(i, j);
        % Newton-Raphson
        z = z0;
        ite = 0;
        fz = f(z);
        while abs(fz) > 1e-6 && ite < 20
            z = z - f(z)/df(z); 
            fz = f(z);
            ite = ite + 1;
        A(i, j) = ite;
figure;
pcolor(X, Y, A);
% hold on
% plot([1, -1, 0, 0], [0, 0, 1, -1], '.k', 'MarkerSize', 20);
% hold off
shading flat
axis tight manual

% xlim([-0.5, 0]);
% ylim([0.5, 1]);
% 保存成视频
% set(gca, 'nextplot', 'replacechildren'); 
% v = VideoWriter('NRfractal.avi');
% open(v);
% for k = 1:20 
%     pcolor(X, Y, A);
%     shading flat
%     xlim([-2*(1-k/25), 2*(1-k/25)]);
%     ylim([-2*(1-k/25), 2*(1-k/25)]);
%     frame = getframe(gcf);
%     writeVideo(v, frame);
% end
% (-0.19, 0.6557)
% (-0.1, 0.651)
% zx = zx*zx - zy*zy + cx
% zy = 2*zx*zy+cy
c = - 0.1 + 1i*0.651;
radius = 32;
[X, Y] = meshgrid(linspace(-1.5, 1.5, n), linspace(-1.5, 1.5, m));
A = nan(n, m);
for i = 1:n
    for j = 1:m
        z = X(i, j) + 1i*Y(i, j);
        % Julia
        for ite = 1:1000
            z = (z*z + c) ;
            if abs(z) > radius
                break;
        A(i, j) = ite;
figure;
pcolor(X, Y, A);
shading flat
axis tight manual

曲线斜线填充

曲面贴图

clear;clc;
figure;
% 读取地图文件
image = imread('World.jpg'); 
% 生成一个球面数据
[x, y, z] = sphere(200);
% 绘制球体
p = surf(x, y, z); 
% 去网格线
shading interp;
p.CData = image; 
% 纹理贴图
p.FaceColor = "texturemap"; 
axis equal;
axis off
% 光源，看起来更有立体感
% light
% lighting gouraud
% 光源颜色
handle = light('Color', [1 1 1]);
t = 0;
while t < 100
    t = t + 1;
    view([t 10]);
    lightangle(handle, t, 0);
    pause(0.01);
end

自定义颜色图

clear;clc;
N = 500;
z = peaks(N);
% 选择 ROI 以外的不显示
for i = 1:N
    for j = 1:N
        if sqrt((i - N/2)*(i - N/2) + (j - N/2)*(j - N/2)) > 240
            z(i, j) = nan;
% 自定义颜色 大概就是给特定范围值指定颜色
N = 14 * 5;
crange = linspace(-6, 8, N);
cmap = zeros(N, 3);
for i = 1:N
    if crange(i) <= 0
        cmap(i, :) = [0, 1, 0];
    elseif crange(i) <= 3
        cmap(i, :) = [0, 0, 1];
    elseif crange(i) <= 6
        cmap(i, :) = [1, 1, 0];
        cmap(i, :) = [1, 0, 0];
figure;
surf(z)
colormap(cmap);
% 去网格
shading interp
view(0, 90);
% 去坐标轴
axis off

gif 动态图

clear; clc;
x = 0:0.01:1;
n = 1:9;
len = length(n);
im = cell(1, len);
% 单独显示每个图
figure;
for idx = 1:len
    subplot(3, 3, idx)
    plot(x, x.^idx, 'LineWidth',3)
    title(['y = x^', num2str(idx)])
% 获取绘制对象
fig = figure(1);
for idx = 1:len
    y = x.^idx;
    plot(x, y, 'LineWidth', 3)
    title(['y = x^', num2str(n(idx))])
%     drawnow
%     pause(0.1);
    frame = getframe(fig);
    im{idx} = frame2im(frame);
% 输出文件名
% filename = 'testAnimated.gif'; 
% for idx = 1:len
%     % 制作gif文件，图像必须是index索引图像
%     [A, map] = rgb2ind(im{idx}, 256);
%     if idx == 1
%         imwrite(A, map, filename, 'gif', 'LoopCount', Inf, 'DelayTime', 0.3);
%     else
%         imwrite(A, map, filename, 'gif', 'WriteMode', 'append', 'DelayTime', 0.3);
%     end
% end

方程曲线图

% 二元方程  x^2*cos(y) + x*sinh(y^2) = 0
xy = linspace(-2, 2, 4);
f = @(x, y) x.^2.*cos(y) + x.*sinh(y.^2);
figure
fimplicit(f, [-2, 2]);

极坐标图

figure;
theta = 0:0.01:2*pi;
rho = sin(2*theta).*cos(2*theta);
tiledlayout(1, 2);
nexttile;
polarplot(theta, rho, 'c', 'LineWidth', 2);
nexttile;
rMax = 2*max(rho);
% 这个看不到线，因为只有一个重复的点
polarplot([0, 2*pi], [rMax, rMax]);    
hold on
polarplot(theta, rho, 'm', 'LineWidth', 2);
hold off

不相交随机圆

clear;clc;close all;
% 限定范围
width = 10;  
height = 10;
% 最多产生的圆的个数
circleNumber = 100;   
% 记录每个圆的横坐标、纵坐标、半径
paras = zeros(circleNumber, 3);  
num = 0;
hold on
while num < circleNumber
    num = num + 1;    
    % 圆半径小于1或者设定为固定值
    r = rand; 
    % 在范围内随机坐标
    xPos = rand*(width-2*r) + r;  
    yPos = rand*(height-2*r) + r;
    % 记录坐标、半径
    paras(num,:) = [xPos, yPos, r];
    % 判断每个圆的位置是否不相切、不相交
    if num > 1
        % 新产生的圆和之前产生的所有圆计算距离        
        xs = paras(1:num - 1, 1);
        ys = paras(1:num - 1, 2);
        rs = paras(1:num - 1, 3);
        dist1 = sqrt((xPos - xs).^2 + (yPos - ys).^2);
        dist2 = abs(r + rs);
        % 如果相离则绘制当前产生的圆，否则就重新生成一个圆
        if all(dist1 > dist2)
            rectangle('Position', [xPos-r, yPos-r, 2*r, 2*r], 'Curvature', [1 1]);
            axis equal
            r = rand; 
            xPos = rand*(width-2*r) + r;  
            yPos = rand*(height-2*r) + r;
            paras(num,:) = [xPos,yPos,r];
            % 防止死循环
            temp = 0;
            maxTry = 100;
            while any(dist1 <= dist2) && temp < maxTry
                temp = temp + 1;
                dist1 = sqrt((xPos - xs).^2 + (yPos - ys).^2);
                dist2 = abs(r + rs);
            if all(dist1 > dist2)
                rectangle('Position', [xPos-r, yPos-r, 2*r, 2*r], 'Curvature', [1 1]);
                axis equal
axis([0 width 0 height])
box on
hold off

BP 神经网络图

figure;
x1 = ones(1, 5);
x2 = 2 * ones(1, 11);
x3 = 3 * ones(1, 8);
y1 = 4:8;
y2 = 1:11;
y3 = 2.5:9.5;
for i = 1:5
    for j = 1:11
        plot([x1(i), x2(j)], [y1(i), y2(j)], 'k');
        hold on
for i = 1:11
    for j = 1:8
        plot([x2(i), x3(j)], [y2(i), y3(j)], 'k');
scatter(x1, y1, 200, 'k', 'MarkerFaceColor', 'r');
scatter(x2, y2, 200, 'k', 'MarkerFaceColor', 'y');
scatter(x3, y3, 200, 'k', 'MarkerFaceColor', 'k');
plot([1.5, 1.5], [0, 11], 'k--');
plot([2.5, 2.5], [0, 11], 'k--');
hold off
axis off
text(1.5, 11.75, '输入层');
text(2, 11.75, '隐藏层');
text(2.5, 11.75, '输出层');

小圆构成的圆环

clear;clc;
x0 = 0;
y0 = 0;
r1 = 2;
r2 = 1;
theta = 0:pi/50:2*pi;
for i = 1:length(theta)
    % 系列小圆的圆心坐标 极坐标方式
    x = x0 + r1 * cos(theta(i));
    y = y0 + r1 * sin(theta(i));
    % 以小圆圆心画圆 极坐标方式
    xx = x + r2 * cos(theta);
    yy = y + r2 * sin(theta);
    plot(xx, yy, 'k');
    hold on
hold off
% 限定显示范围
xlim([-3, 3]);
ylim([-3, 3]);
% x y 轴等宽
axis equal
axis tight

棋盘格

figure;
% 生成数据点
[x, y] = meshgrid(30:39);
x = x(:);
y = y(:);
scatter(x, y, 100, 'red');
hold on
% 随机填充几个点
number = 5;
index_x = randi(9, 1, number) + 30;
index_y = randi(9, 1, number) + 30;