GENG1003 Introduction to Procedural Programming

MATLAB

What is MATLAB?

MATLAB is one of a number of commercially available, sophisticated mathematical computation tools

Good for:

Numerical calculations

Especially involving matrices

Graphics

MATLAB stands for Matrix Laboratory

Easy to use

Versatile

Built in programming language

Not a general purpose language like C++ or Java

How is MATLAB used in Industry?

Widespread, especially in the signal processing field

Tool of choice in Academia for most engineering fields

Some examples.

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.

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.

Fluid Dynamics

Results from a finite element analysis code were post processed

using MATLAB to create this image.

Problem 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

1. State the Problem

If you dont have a clear understanding of the problem, its unlikely that youll be able to solve it

Drawing a picture often helps you understand the system better

2. Describe the Input and Output

Be careful to include units

Identify constants

Label your sketch

Group information into tables

3. 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

4. Solve the problem

Create a MATLAB solution

Be generous with comments, so that others can follow your work

5. 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

Example

E = mc2

The sun is fueled by the conversion of matter to energy

How much matter does the sun consume every day?

State the Problem

Find the amount of matter necessary to produce the amount of energy radiated by the sun everyday

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

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 =

( )2831

sec/100.3

1033.3

m

Jm

=

22

14

sec/107.3

m

J=

But the units are still wrong.

1 J = 1 kg m2/sec2

kgm

mkg 1422

2214 107.3

sec/

sec/ 107.3 ==

14

2 23.7 10

/ sec

J

m

Well start learning the details of how to use MATLAB in the next lecture.

However, you can see from the following demonstration just how easy it is to use the command window

Develop a MATLAB Solution to Solve the Problem

Develop a MATLAB Solution to Solve the Problem

Test your Solution

Matches the hand solution

Is it reasonable?

Consider

Mass of the sun = 2*1030 kg

How long would it take to consume all that mass?

Test your Solution

Only 10% is available for hydrogen fusion in its core.

So, effectively, the available mass is 2*1029 kg

Also, hydrogen fusion only converts 0.68% of the mass into energy.

Therefore, the mass effectively used is only 2*1029 * 0.68 / 100 =1.4*1027 kg

time = (mass of the sun)/(rate of consumption)

Thats 10.3 billion years!!

Yes this is a reasonable result. The sun is believed to be 4-

5 billion years old and should have another 5 billion years

ahead of it, until it burns all its hydrogen and starts burning

helium. It will become a red giant, swallow Mercury, Venus,

Earth and Mars, and then collapse and become a cold, white

dwarf star.

Test your Solution

time = 1.4*1027 kg * year = 1.03*1010 years

3.7*1014 kg/day 365 day

Use the Help

Use the Help

Use MATLABs Help