Mesh data generation function meshgrid

Want to draw a three-dimensional picture , Getting grid coordinates is very important ,matlab There's a name meshgrid Function of , It is easy to generate gridded coordinates according to parameters , Of course , These gridded coordinates are generated by a specific calculation method .

grammar ：

[X,Y] = meshgrid(x,y)

[X,Y] = meshgrid(x)

explain ： Here is the first way ,x,y Is a vector , And the resulting X,Y It's a matrix . among X Each line of is made up of x The numbers in form in order ,Y Each column of is composed of y The numbers in form in order .

The second way is essentially x And y An abbreviation in the case of equality .

Let's look at some examples ：

>> x=1:4

x =

1     2     3    4

>> y=1:5

y =

1     2     3    4     5

>> [X,Y]=meshgrid(x,y)

X =

1     2     3    4

1     2     3    4

1     2     3    4

1     2     3    4

1     2     3    4

Y =

1     1     1    1

2     2     2    2

3     3     3    3

4     4     4    4

5     5     5    5

It can be seen that , Generated X,Y The dimensions are the same , The same location data forms a group of numbers （ coordinate ）, This forms a grid .

Of course , There is another way to generate grid data ,

>> x=1:4

x =

1     2     3    4

>> y=(1:5)'   

y =

1

2

3

4

5

>> X=ones(size(y))*x

X =

1     2     3    4

1     2     3    4

1     2     3    4

1     2     3    4

1     2     3    4

>> Y=y*ones(size(x))

Y =

1    1     1     1

2     2     2    2

3     3     3    3

4     4     4    4

5     5     5    5

The results of the two methods are the same , Of course ,meshgrid Functions are much more complex , Interested can be found in matlab Command line input edit meshgrid, open meshgrid Look at the function . After getting the grid data , Then you can draw three-dimensional graphics .

>> Z=X.^2+Y

Z =

2     5    10   17

3     6    11   18

4     7    12   19

5     8    13   20

6     9    14   21

>> surf(X,Y,Z)

Such a three-dimensional figure has been drawn , In essence, it is to combine two-dimensional coordinates with the third coordinate to form three-dimensional coordinates , Then connect , Fill the resulting surface .

My public number ： Simple programming journey

Welcome to your attention ！