在Matlab中绘制3-D图形和水平曲线

Question

我在下面有以下代码，但是由于我现在还没有Matlab，所以我无法对其进行测试，恐怕我最终拿到它时可能没有时间自己进行测试。 我正在尝试在三种不同类型的函数的y和x轴（仅二维）上绘制3-d图和水平曲线图。 如果有人可以指出下面的代码有什么问题，我将不胜感激。

**************************************************************
**plotting functions -- level curves and 3d graph** 

x_val = linspace(0, 100, 200); 
y_val = linspace(0, 100, 200); 
[x, y] = meshgrid(x_val, y_val); 
z = ln(x).+y.;  
figure 
contour3(y, x, z)
contour(y, x, z)


********************************

z = (x.^1/2)+y.;  
figure 
contour3(y, x, z)
contour(y, x, z)

*********************************


z = (x.^1/3)+y.; 
figure 
contour3(y, x, z)
contour(y, x, z)

Answer 1

除了上面提到的点和注释格式过多之外，ln不是有效的matlab符号。 以下内容在Matlab上运行。

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%plotting functions -- level curves and 3d graph%% 

x_val = linspace(0, 100, 200); 
y_val = linspace(0, 100, 200); 
[x, y] = meshgrid(x_val, y_val); 
z = log(x)+y;  
figure 
contour3(y, x, z)
figure 
contour(y, x, z)


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

z = (x.^1/2)+y;  
figure 
contour3(y, x, z)
figure 
contour(y, x, z)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


z = (x^1/3)+y; 
figure 
contour3(y, x, z)
figure 
contour(y, x, z)

Answer 2

首先，MATLAB中的注释是“％”而不是“ *”。

我认为您有一些错误，尝试执行元素明智的运算符。

您对z的三个分配有太多的点：

 z = log(x)+y;  
 z = (x.^1/2)+y; 
 z = (x.^1/3)+y; 

不需要使用“。+”，因为MATLAB会自动按元素添加矩阵。