Megha Sunny Lesson -1 October Summary of Lesson: Introduction to MATLAB

Transcription

1 Megha Sunny Lesson -1 October Summary of Lesson: Introduction to MATLAB This lesson was just the beginning of the series of tutorial type lessons on MATLAB. It gives an introduction to basic computational programming using MATLAB. It explains what is MATLAB programming, what is the purpose of learning it, how to do calculations in MATLAB, assigning arrays and plotting. A video, how small is nano was shown as launch to develop an understanding of the size range of a Nano particles. Metric system prefixes were introduced to students and were incorporated in the practice problem. The ultimate goal in the classroom is to have the students be able to write their own code to model labs both theoretically and experimentally. The first lesson was an introduction to MATLAB. After getting familiarized with the MATLAB interface, command window, workspace, and command history, students will learn to do simple calculations in MATLAB. Some common commands they are going to be using are logs, trig functions, exponentials, etc. They will also learn how to name a variable, assign an array, and plot a function in MATLAB. Students will practice the MATLAB commands in their laptops while going through the presentations. There is a practice problem at the end of the presentation. A MATLAB Quick Reference sheet with some basic MATLAB commands was given to students for their reference.

2 Teacher: Megha Sunny Period: Lesson Plan 1 Date(s): October SETTING THE STAGE Essential Question Science Lesson Plan How to solve problems in MATLAB? In this lesson we will introduce basic MATLAB programming and Metric system prefixes. Content Objective(s) (Student-friendly) Connection to previous or future lessons Understand the basics of computational programming using MATLAB. This is the first lesson. It will give you an idea about basic MATLAB programming and how MATLAB is used to solve math problems. Critical Thinking Questions Key Vocabulary What is MATLAB? What is the purpose of learning MATLAB? How to solve problems in MATLAB? How to assign an array in MATLAB? How to plot a function in MATLAB? Array, plot, bar Materials Needed/Safety Laptops, MATLAB, Pencil, Paper ACTIVE INSTRUCTION Launch (Engage) Will show a video How small is nano and introduce the Metric system prefixes. Investigation (Explore) TIME FOR REFLECTION Summarization (Explain & Extend) Students will learn about MATLAB programming and how to solve their math problems in MATLAB. They will learn about assigning an array in MATLAB and plotting a function in MATLAB. Assessment Observation *This template is available in electronic form. 1

3 (Evaluate) Listening Questions Science Lesson Plan Homework None *This template is available in electronic form. 2

4 Introduction to MATLAB Ayse Kalkan- Savoy NSF GK- 12 Fellow Vibes and Waves in Action Center for Advanced Computation and Telecommunications University of Massachusetts Lowell Altered by Megha Sunny NSF GK- 12 Fellow Vibes and Waves in Action Center for Advanced Computation and Telecommunications University of Massachusetts Lowell 4 October 2012

5 What is MATLAB? * MATLAB is a scripting language that is often used to solve scientific and mathematical problems * Useful for Solving Equations Simplifying functions 2D- 3D plotting * Makes calculations easier when there are big sets of numbers

6 MATLAB Launch Matlab - Go to: Start> All Programs > Matlab - Double click MATLAB R2011a - Be patient it takes time for the application to start

7 MATLAB Desktop Current Directory Command Window: a big calculator Workspace Command History

8 Matlab Calculations * Basics: * Add : + * Subtract: - * Divide: / * Multiply: * * Try: * 3 Question: Does Matlab follow the order of operations?

9 Order of Operations * Matlab follow the order of operations. * Multiplication and division are computed before subtraction and addition (4 * 3) - > This is what Matlab computes!

10 Some MATLAB Commands * Try sqrt(121) sqrt(100); abs(- 10) 2^2 2^3 Question: What are sqrt, abs, and ^?

11 Variables/Numbers It is good to name numbers. Example : a = 20.2 b = 10.1 c = 3*a+b d=pi e=3*pi/2 We call a, b, c, d and e variables.

12 Arrays * Matlab is designed to work with large sets of numbers. * A variable can point to a set of numbers. * If a variable is a list of numbers, it is called an ARRAY. * Array Example: x = [ ]; * We can reach each element of an array by using its position in the array. Example: x(4) This will print 6. Let s change its value to 7. x(4) = 7

13 Add/Remove Numbers * Add a number to the beginning of the array: x = [- 1 x] * Add a number to the end of the array: x = [x 12] * Remove a number from the array: * Example: Remove 3 rd element x(3) = []

14 Arrays and Scalars * Scalar Array Operation * y = 2*x * The right format for scalar- array operation is using a dot before the operation: * y = 2.*x * Array Array Operation * z = x + y

15 Plots * To open a plot window: * figure() * Plot x vs. y * plot(x,y) * Title of your plot * title( My Test Plot ) * Label axes * xlabel( x ); ylabel( y )

16 Plotting Multiple Data Sets * Plot x vs. y and x vs. z in one graph. * plot(x,y, b,x,z, g ) * xaxis( x ) * yaxis( y ) * title( My Test Plot ) * legend( x vs y, x vs z ) * legend( x vs y, x vs z, Location, SouthEast ) * grid Can you increase the line width of the graph?

17 * plot(x,y, b,x,z, g, LineWidth,2)

18 Example * Nano size objects Object Diameter (nanometers) * Sugar Molecule 1 * DNA 2.5 * Carbon Nanotube 4 * Cell Membrane 10 * Virus 100

19 Exercise * Create an array to hold diameters. * Plot the data. * See what bar command does. * Use: doc bar * Have a title for your graph. * Label the axes. * Which object doesn t fit well with the other objects? * Remove that object from the array and plot again. * Can we create an array for objects and use that to label the x- axis?

20 Matlab commands for the * diameters = [ ] * bar(diameters) * title( Size Comparison of Objects within the Nanoscale') * xlabel( Objects') * ylabel( Diameter (nm)') * diameters(5)=[] * Bar(diameters) example * set(gca,'xticklabel',{ Sugar Molecule, DNA, Carbon Nanotube, Cell Membrane })

21 Basic Plotting Operators Line Style - Solid line (default) -- Dashed line : Dotted line -. Dash-dot line Marker + Plus sign o Circle * Asterisk. Point x Cross s Square d Diamond ^ Upward pointing triangle > Right pointing triangle < Left pointing triangle p Five-pointed star (pentagon) h Six-pointed star (hexagon) x Cross s Square d Diamond ^ Upward pointing triangle > Right pointing triangle < Left pointing triangle p Five-pointed star (pentagon) Color r Red g Green b Blue c Cyan m Magenta r Red Axis Control axes Create axes in arbitrary positions axis Control axis scaling and appearance box Display axis border grid Control Grid Lines hold Hold current graph rotate3d Interactively rotate view of 3D plot subplot Create axes in tled positions view Set #-D graph viewpoints specs. zoom zoom in and out on 2-D plot Plot 2D plot plot(x,y) : plots a graph of y = f(x) Label ** First plot a graph than label it** xlabel( x-axis ); labels x-axis, make sure open and close the parenthesis, and add single quotation mark at the beginning and at the end. x-axis ylabel( y-axis ); labels y-axis title( y vs. x ); to display a title at the top location of the graph Specifiers Examples (line color, line style, etc ) plot(x,y, *r ) à Points are marked with * and red plot(x,y, - -m ) à line is dashed and magenta Matlab Quick Reference

22 M-Files New M-Files File New M-File (opens blank page) Open M-Files File Open Select a desired M-File Click Open Save M-Files New File Save As Select a folder where you want to save your new M-File Old File Save (Ctrl + S) Naming M-files 1. Must begin with a letter 2. Can include digits & underscores 3. NO SPACES!! Use an underscore_ **Format for our class** P#_PROJECTNAME_lastname_ firstname_ YYMMDD Variables Variable_Name = Numerical Value or Computable expression **Same rules apply as naming M-Files** A = 5 b = 10-6 p = pi C = A-b Numerical Assignment Computable Expression Special Assignment Result of operation with variables Data Stored as Vectors and Matrices Row vector A = [ ]; leave space between each number. This generates 1 x 4 row vector Column vector B = [1; 2; 3; 4]; add semicolon(;) between each number. This generates 4x1 column vector Simple Vector: T=Begin:Interval:End Example: T=300:10:400 Linspace t= linspace(xmin,xmax,n) à Returns a vector of n linearly spaced numbers between (& including) xmin & xmax Example: Y = linspace(1,10,5); Returns a vector of 5 linearly spaced numbers between 1 & 10 Basic Math Operators sqrt(x) Square Root nthroot(x,n) Real nth root or a real number x. exp(x) Exponential (e! ) abs(x) Absolute Value log(x) Natural Logarithm (Base e, (ln)) log10(x) Base 10 logarithm factorial(x) Factorial of x, x! sin(x) sind(x) cos(x) cosd(x) tan(x) tand(x) Trig Operators Sine of x, radians Sine of x, degrees Cosine of x, radians Cosine of x, degrees Tangent of x, radians Tangent of x, radians Operators & Special Characters +,-,*,/ Matrix Math Operators.*,./ Array Multi. And Div. ^,.^ Matrix & Array Power % Comment Transpose or quote for string ; Denote new row in matrix definition, or at the end of a command suppress output : Create linearly spaced vectors ( ) Index into matrix (A(3,2) pulls the 3 rd row, 2 nd column of A) and enclosed function input arguments [ ] Create Matrix (A = [1 2; 3 4], x = [1 2 3]), Separate commands and elements in matrix clc Clears the command window clear all Clears all variables, globals, functions close all Closes all open figure windows who Displays list of variables in memory whos Displays variables with their size 5 6] HER BROCHURE TIPS