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ee370matlab [2012/08/13 13:29] (current)
beard created
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 +====== Matlab Hints and Commands ======
  
 +Useful commands
 +
 +Here is a selection of useful MATLAB commands that can help make your life easier. The help pages for MATLAB are excellent. Many of them have a lot more functionality but we are showing them here as they are commonly used in 370. Type "help *" at the command line to get common operators such as "​+"​ and "​-"​.
 +
 +
 +__BAR(X, Y)__
 +
 +Plots a bar graph of x values with heights of y.
 +
 +__CLF__
 +
 +Clears your currently active figure.
 +
 +
 +__CONV(X,​Y)__
 +
 +Convolution of x vector with the y vector (make sure that they are both row vectors).
 +
 +
 +__IF,​ELSE,​END__
 +
 +This allows you to do conditional statements. For example:
 +
 +    if (point(1,i) < 0.5) && (point(2,i) < 0.5)
 +        plot(point(1,​i),​ point(2,i), '​xr'​)
 +        count = count + 1;
 +    else
 +        plot(point(1,​i),​ point(2,i), '​xb'​)
 +    end
 +
 +This code evaluates the top statement, that is if my point i is found less than x < 0.5 and y < 0.5. If it is, then it plots that point as a red "​x"​ and counts it. If it is not, then it plots the point as a blue "​x"​. You can use an "​if"​ statement without the else. Make sure you include the "​end"​! To evaluate conditional statements, you need "​relational operators"​ as indicated below.
 +
 +__FOR__
 +
 +This allows you to have a for a loop with an increment. For example:
 +
 +    N = 10;
 +    count = 0;
 +    for i=1:N
 +        count = count + 1;
 +    end
 +
 +This allows you to count from 1 to N, which in this case is 10. Your count is the number of times you passed through the for loop.
 +
 +__HIST(X)__
 +
 +Plots a histogram of the values of x. It automatically divides the values into bins and then counts how many occur.
 +
 +__MULTIPLICATION__
 +
 +We may want to do specific things. ​
 +"​*"​ is regular matrix multiplication.
 +"​.*"​ is the element by element multiplication.
 +
 +__PLOT(X, Y)__
 +
 +Plots a graph of x values on the x-axis and y values on the y-axis. The default is for a line to connect the points. If you want to plot differently,​ for example, x's, then you can type in plot(x, y, '​xr'​) and it will plot the values with "​x'​s"​ and the color red.
 +
 +__RANDOM__
 +
 +This for example can be used like X_vector=random('​Poisson',​ 3, 1, 10) where this produces a vector of outcomes of a Poisson random variable with parameter 3 and vector of 1 row with 10 columns. This also works for '​Bionomial',​ '​Geometric'​ and others.
 +
 +__RELATIONAL OPERATORS__
 +
 +"&&"​ and
 +"​||"​ or
 +"​=="​ equals (make sure they are of the same type, i.e. double)
 +"<"​ less than
 +"<​="​ less than or equal
 +">"​ greater than
 +">​="​ greater than or equal
 +
 +__SUM__
 +
 +This sums up everything in your vector.
 +
 +__XLIM([X1 X2])__
 +
 +This limits the range on your x axis of your figure to the interval x1 to x2.
 +
 +__YLIM([Y1 Y2])__
 +
 +This limits the range on your y axis of your figure to the interval y1 to y2.