Matlab Notes_Scripts, Functions and Plots-學習記筆

Matlab Notes-Scripts, Functions and Plots

Scripts and Functions

• A script file called an m-file (with an extension .m), which is only a text file that contains each line of the file as though you typed them at the command prompt.

• Creating a block of code is through subroutines. These are called functions, which also allow us to extend the capabilities of MATLAB. In fact a major portion of MATLAB is assembled using function files in several categories and using special collections called "toolboxes".

• A major difference between script and function files is that the first executable line in a function file begins with the keyword function followed by an output-input variable declaration.

Applications of Plots with Functions and Scripts

• References:(link_1 ), (link_2 )

Plotting a Sinusodial Wave of

• Function

  function plot_sin(n,t)
  x=sin(n*pi*t);
  plot(t, x, 'b'); %plot the graph with color "black"
  xlabel('t in sec'); ylabel('sin(n*pi*t)'); %setting labels for x and y axises
  title('plot of sin(n*pi*t)'); %setting title for the plot 

• Script

  t=0:0.01:1; n=2;
  plot_sin(n, t);

• Result

  • 

Plotting a Discrete-Time Signal of

• Function

  function plot_dt_sin(k,n)
  x=sin(k*pi*n);
  x_plot = stem(n, x, 'b', 'filled'); %stem plot
  set(x_plot, 'markersize', 4); %chagne the size of the circle
  xlabel('n'); ylabel('sin(k*pi*n)'); %setting labels for x and y axises
  title('plot of sin(k*pi*n)'); %setting title for the plot

• Script

  n=0:1:20; k=0.1;
  plot_dt_sin(k, n);

• Result

  • 

Creating Two or More Plots Simultaneously

• We can do so by using . (link )

• Basic Usage

  %Adding the followings line
  subplot(rows, columns, which row, order);

• Result of subplot(2, 1, 1) and subplot(2, 1, 2)

  •