matlab for engineers about matlab chapter 1. matlab for engineers what’s in this chapter? what is...
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Matlab for Engineers
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About Matlab
Chapter 1
Matlab for Engineers
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What’s in this Chapter?
• What is Matlab?
• Student Edition of Matlab
• How is Matlab used in industry?
• Problem Solving in Engineering and Science
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Section 1.1 What is Matlab?
• Matlab is one of a number of commercially available, sophisticated mathematical computation tools
• Others include• Maple• Mathematica• MathCad
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Matlab excels at
• Numerical calculations• Especially involving matrices
• Graphics
• Matlab stands for Matrix Laboratory
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Why Matlab
• Easy to use
• Versatile
• Built in programming language
• Not a general purpose language like C++ or Java
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Matlab was originally written in Fortran, then later
rewritten in C
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Matlab 7
• Matlab is updated regularly
• Versions that predate Matlab 5.5 are substantially different
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Release Numbers
• The Mathworks packages their software in groups, called releases
• Release 14 includes• Matlab 7• Simulink 6.1• A number of specialized “toolboxes”
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New Release Naming System
• During Spring 2006 Matlab changed to a new system for naming their releases
• They will be issuing updates twice a year
2006a
2006b
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Section 1.2Student Edition of Matlab
• Matlab comes in both a student and professional edition
• Student editions are available for• Windows Operating Systems• Mac OS• Linux
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The student edition of release 14 includes
• Full featured Matlab 7
• Simulink 6.1 – limited to 1000 blocks
• Major portions of the Symbolic toolbox
• Other toolboxes may be purchased separately
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The command prompt is the biggest difference you’ll
notice
>> is the command prompt for the professional version
EDU>> is the command prompt for the student version
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Section 1.3How is Matlab used in
Industry?
• Widespread, especially in the signal processing field
• Tool of choice in Academia for most engineering fields
• Some examples….
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Electrical Engineering
These images simulate the visual system used in a housefly brain to detect collisions. The techniques developed are being used in autonomous robot systems that depend upon vision for navigation. The data was processed using Matlab
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Biomedical Engineering
These images were created from MRI scan data using Matlab. The actual data set is included with the standard Matlab installation, allowing you experiment with manipulating the data yourself.
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Fluid Dynamics
Results from a finite element analysis code were post processed using Matlab to create this image.
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Section 1.4Problem Solving in
Engineering and Science
1. State the Problem
2. Describe the input and output
3. Develop an algorithm
4. Solve the problem
5. Test the solution
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State the Problem
• If you don’t have a clear understanding of the problem, it’s unlikely that you’ll be able to solve it
• Drawing a picture often helps you understand the system better
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Describe the Input and Output
• Be careful to include units
• Identify constants
• Label your sketch
• Group information into tables
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Develop an Algorithm
• Identify any equations relating the knowns and unknowns
• Work through a simplified version of the problem by hand or with a calculator
• Developing a flow chart is often useful for complicated problems
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Solve the problem
• Create a Matlab solution
• Be generous with comments, so that others can follow your work
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Test the Solution
• Compare to the hand solution• Do your answers make sense
physically?• Is your answer really what was
asked for?• Graphs are often useful ways to
check your calculations for reasonableness
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If you use a consistent problem solving strategy you increase the chance that your result is correct
Here’s an example….
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Example 1.1
• Albert Einstein• E=mc2
• The sun is fueled by the conversion of matter to energy
• How much matter does the sun consume every day?
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State the Problem
• Find the amount of matter necessary to produce the amount of energy radiated by the sun everyday
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Describe the Input and Output
• Input• Rate of energy radiation
• E = 385*1024 Joules/second
• Speed of light• c = 3.0*108 meters/second
• Output• Mass in kilograms
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Develop an Algorithm – Hand Example
• The energy radiated in one day is:
• Rearrange E=mc2 and solve for m• m=E/c2
Jdayday
hours
hour
J 3124 1033.31*24sec
3600sec
10385
28
31
sec/100.3
1033.3
m
Jm
2214
sec/107.3
m
J
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But the units are wrong!!
1 J = 1 kg m2/sec2
kgm
mkg 1422
2214 107.3
sec/
sec/ 107.3
142 2
3.7 10/ sec
J
m
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Develop a Matlab Solution to Solve the Problem
• We’ll start learning the details of how to use Matlab in the next chapter.
• However, you can see from the following demonstration just how easy it is to use the command window
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To restart the demonstration click in the Matlab window
Use the down arrow on the keyboard to proceeed to the next slide
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Test your Solution
• Matches the hand solution
• Is it reasonable?
• Consider…• Mass of the sun = 2*1020 kg• How long would it take to consume
all that mass?
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r time = (mass of the sun)/(rate of consumption)
yearsdays
year
daykg
kgtime 13
14
30
105.1365
*/107.3
102
That’s 15 trillion years!!Yes – this is a reasonable result
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Summary
• Matlab is widely used
• Matlab is easy to use
• A systematic problem solving strategy makes it more likely you’ve found the right answer