Difference between revisions of "Likelihood"
From Sean_Carver
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help rand | help rand | ||
| − | Returns help for the rand command. | + | Returns help for the rand command. We'll discuss this help file. Try |
| + | |||
| + | rand(3) | ||
| + | rand(3,2) | ||
| + | rand(3,2,2) | ||
| + | |||
| + | These commands allow you to create arrays of random numbers without loops. Compare | ||
| + | |||
| + | A = rand(10000,1); | ||
| + | |||
| + | With | ||
| + | |||
| + | for i = 1:10000 | ||
| + | B(i,1) = rand; | ||
| + | end | ||
| + | |||
| + | Note however there is really two issues with the second method: first, we could have avoided the loop, and second, the we successively building a larger and larger array without first initializing it. Now that B is defined, repeating the second set of command will go much faster. | ||
Revision as of 15:12, 23 January 2009
Random Numbers in MATLAB
Start MATLAB and type the following into the MATLAB prompt
rand
This produces a random number. Repeat several times. Continue typing the material in boxes into the MATLAB prompt.
help rand
Returns help for the rand command. We'll discuss this help file. Try
rand(3) rand(3,2) rand(3,2,2)
These commands allow you to create arrays of random numbers without loops. Compare
A = rand(10000,1);
With
for i = 1:10000 B(i,1) = rand; end
Note however there is really two issues with the second method: first, we could have avoided the loop, and second, the we successively building a larger and larger array without first initializing it. Now that B is defined, repeating the second set of command will go much faster.
