tutorial matlab2

8/2/2019 Tutorial Matlab2

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-Class ECES-304

Class ESA251

resen e y : u am a

Presented by : Elmi Abu Bakar



Content s

Polynomials

Functions

Programming

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I. Polynomials - Funct ions

Polynomial funct ions : in the MATLAB polyfun dir ectoryT e ‘ hel ol fun ’

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I. Polynomials –Represent at ion & Evaluat ion

Representation : polynomials as row vectors containingcoefficients ordered by descending powers.

va uat on : po yva unct on eva uates a po ynom a at aspecified value.

Possible to evaluate a polynomials in a matrix sense.

I : ident it y mat rix

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I. Polynomials –Root s

‘roots ’ funct ion calculates t he root s of a polynomial:

‘ ’

‘ ’ ‘ ’ ,

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I. Polynomials –Derivat ives

‘polyder ’ funct ion computes t he derivat ive of any polynomial.

derivative of the product a*b by ‘ polyder ’ with a single output

derivat ive of t he quot ient a/ b by ‘ polyder ’ with two output

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I. Polynomials –Convolut ion

‘conv ’ computes convolut ion operat ion

‘deconv ’ computes deconvolut ion operat ion

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I. Polynomials –Part ial Fract ion Expansions

‘residue ’ f inds t he par t ial f ract ion expansion of t he rat io of twopolynomials

so, res ue conver s ac opolynomial form

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I. Polynomials –Polynomial Curve Fit t ing

‘polyfit ’ f inds t he coeff icient s of a polynomial t hat f it s a set ofdata in a least -squares sense

x an y are vec ors con a n ng e x an y a a o e e , an n sthe degree of t he polynomial t o return

A third degree polynomial t hat approximately fit s t he dat a

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I. Polynomials - Examples

Example

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I. Polynomials - Examples

Example

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I. Polynomials

Example

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II. Funct ions –Work wit h M-f iles

M-fileWhen ou writ e a MATLAB function or scri t , ou save it t o a f ilecalled an M-f ile (named aft er i t s .m file extension)

Simple f unct ions in M-f ile

Funct ion Definit ion Line

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Simple f unct ions in M-f ileThe Funct ion or Scri t Bod : all the MATLAB code that erformscomputations and assigns values to output arguments.

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Creat ing a Simple M-f ile

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Example (sind.m)

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Example (sind.m)

* fplot : Plot funct ion

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Primary M-file funct ionsThe first funct ion in an M-fi le

Nested Funct ions

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SubfunctionsM-f iles can contain code for more t han one funct ionM-f iles can contain code for more t han one funct ion

Each subfunction begins with it s own funct ion definit ion line

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III. Programming –Operat ors

Arit hmetic operatorsFor numeric com utat ions, element s of arra s wit h e ual dimensions

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Relational operatorsRelat ional o erators com are o erands uant it at ivel

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Logical OperatorsElement -wise —o erat e on corres ondin element s of lo ical arra s.

Short -circuit —operate on scalar, logical expressions.

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Example

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III. Programming –Cont rol St at ement s

Condit ional cont rol : if , elseif , else‘if’ evaluat es a lo ical ex ression and executes a rou of st at ement swhen the expression is t rue.The opt ional ‘ elseif ’ and ‘ else ’ provide for t he execut ion of alt ernat e

rou s of st at ement s.

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Example of ‘ if ’

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Condit ional cont rol : swi t ch, case, otherwiseswitch executes certain statements based on the value of a variable orexpression

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Example : switch, case,

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Loop cont rol : for, while, cont inue, break‘ for’ : t o loo a s ecific number of t imes.‘ whil e’ : more suit able for basing the loop execut ion on how long acondition continues to be true or false.‘ ’ ‘ ’ .

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Example : for

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Example : for

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Example : for

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Example : for

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III. Programming - Development

Planning t he ProgramUsin Pseudo-CodeSelect ing t he Right Data St ructures

General Coding PracticesNaming a Function UniquelyThe Importance of Comments

Making Modificat ions in St epsFunct ions with One Call in Funct ionTesting the Final Program

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tutorial matlab2

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