Managing Workspace in Matlab: load-KURSUS MATLAB ONLINE Skripsi, Tesis, DISERTASI 081219449060

big =    Inf EDU» big2=2^realmax big2 =    Inf 16.9       Strings • Not all real-world objects are best represented by numbers - e.g., names, addresses, units of measurement • A common type supported by most languages (including Matlab) is the String - a collection of characters • Indicated by the single-quote ' EDU» str1='My first string' str1 = My first string EDU» findstr(str1,'first') ans =      4 EDU» strcmp(str1,'My') ans =      0 EDU» strncmp(str1,'My',2) ans =      1 EDU» str2='45.6' str2 = 45.6 EDU» str2num(str2) ans =    45.6000 EDU» strcat(str1,str2) ans = My first string45.6 16.10     Managing Variables • The variables created during a Matlab session are not persistent objects: - they cease to exist when the session is over - endure for the duration of the session • Matlab provides the following commands for managing the workspace 16.10.1 clear • delete a variable now EDU» x=7.9 x =     7.9000 EDU» clear x EDU» x ??? Undefined function or variable 'x'.

• Useful if you wish to ensure that a variable starts with no value - initialisation 16.11     Managing Workspace in Matlab: load • Load in a variable that has previously been saved from Matlab or another source EDU» linear=1:10 linear =      1     2     3     4     5     6     7     8     9    10 EDU» save linear EDU» clear linear EDU» linear ??? Undefined function or variable 'linear'.

EDU» load linear EDU» linear linear =      1     2     3     4     5     6     7     8     9    10 • Useful for large and/or important data 16.12     Managing Workspace: save • Save a matlab variable to a file for usage in a later session EDU» squares=linear.^2 squares =  1     4     9    16    25    36    49    64    81 100 EDU» save mydata linear squares EDU» clear linear squares EDU» squares ??? Undefined function or variable 'squares'.

EDU» load mydata EDU» squares squares =  1     4     9    16    25    36    49    64    81 100 16.13     Review • Variables & identifiers • Data types in Matlab - implications • Special Constants & Variables - inf & nan • Complex numbers • Strings • Managing variables 17           I/O IN MATLAB • All programming languages possess instructions for obtaining input (generally from the user) and outputting results - without input a program always computes the same result - without output a program is effectively useless • Matlab has an unusual mixture of I/o instructions - a simple input and output statement useful in most cases - a set of more complex functions heavily based on C’s fprintf & fscanf • Today’s lecture looks at: - the syntax of these statements - how they can be used to increase the functionality of programs References:        For Engineers (Ch. 1, 8)                                                             User’s Guide (Ch. 3, 4)                                                             Mastering (Ch. 3, 4, 5) 17.1       Basic Input • Matlab has a simple, single statement known as input that serves to both:  - prompt for an input and - return what the user read.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com 17.1.1    The Input Statement • General syntax <variable> = input(prompt-string); e.g., height=input(‘Enter the initial drop height ‘); meanWeight=80.0;          % Mean weight of a single                                                                            % aicrew member in kgs crewWeight = meanWeight * …      floor(input(‘How many air-crew today? ‘)); • Function: -              print the prompt-string on the screen (without a return character) -              wait for the user to enter a value at the keyboard -              place that value in the variable on the left-hand-side of the expression 17.2       Inputting Strings • By default the input statement reads only numeric values -              see below regarding expressions -              must explicitly state we are reading a string <variable>=input(prompt,string-read); e.g., name=input(‘Please enter your name’,’s’); 17.3       Behaviour of Input Statement • Consider the following example: >> ex1=input('1st number...') 1st number...10 ex1 = 10 >> ex2=input('2nd input...') 2nd input...34 45 ??? 34 45        | Unrecognized operand or partial expression.

2nd input...34 ex2 = 34 >> ex3=input('3rd input...') 3rd input...ex2*100 -ex1 + 7.6 ex3 = 3.3976e+03 • Will re-prompt until acceptable input received • Will accept expressions in the Matlab language! - shouldn’t seek to exploit this fact (but how to stop users?) 17.4       Micro: Amoeba Expansion %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % micro.m % A colony of micro organisms grows at such a % rate that its population doubles after a % specified number of hours.The user supplies an % initial population size, name for the species, % and interval required to double in size and % the script charts the progress for the first % 48-hours.

% A modification of the amoeba script to % illustrate the utility of the input statement.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com % Author: Spike % Date:   15/2/1999 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% species = input('What is the organism''s name? ','s'); initialNum = input('Please enter the initial number of species...'); doublePeriod = input('Please enter the number of hours required for the population to double...'); interval = 0:48;                  % Two days population = initialNum*2.0.^(interval/doublePeriod); combined = [interval ; population]; disp(strcat(species,' Organism Population')); disp('Hour            Population'); fprintf('%d\t%6.0f\n',combined); plot(interval,population,'-+'); xlabel('Hours'); ylabel('Population'); 17.5       Micro Run >> micro What is the organism's name? little-us nastius Please enter the initial number of species...1e5 Please enter the number of hours required for the population to double...5.34 little-us nastius Organism Population Hour      Population 0             100000 1  113860 18           1034446 19           1177824 20           1341075 45           34416732 46           39187024 47           44618498 48           50802794 17.6       Basic Output • Matlab has a simple single statement called disp for displaying values -              displays literals and values of variables -              format controlled by a separate command 17.6.1    The disp Statement • General forms: disp(variable);                    OR disp(expression); e.g., >> disp(ex1);     10 >> disp('Text such as for table headings'); Text such as for table headings >> disp('The value of ex2=',ex2); ??? Error using ==> disp Too many input arguments.

>> disp(strcat('10 times ex2 equals ',num2str(10*ex2))); 10 times ex2 equals340 • Displays only a single argument • Argument can be an expression 17.7       The format command • Matlab has a default behavior when outputting numeric values: -              if value is a whole number then display as an integer -              otherwise if there’s about 5 significant digits or less then display as a float -              otherwise display it in scientific notation • Matlab provides a number of different possible formats for showing numeric values - specified with the format instruction - applies for all disp (and variable name) output until the format is changed with another format instruction.

Command           Explanation format short       5 digits, also the default format Format long        16 digits format short e    5 digits in exponential form format long e     16 digits in exponential form format short g    “better” of short or short e format long g     “better” of long or long e format hex          As a hexadecimal number format  bank       To 2 decimal places (like currency) format +              Sign of value only format rat           As a  rational approximation 17.8       Format Examples • format instructions should be used in conjunction with disp to ensure the output answers are in the most appropriate form.

Note: format does not change the actual value of the variable being displayed, it simply alters the display format.

e.g., >> format short; disp(pi);     3.1416 >> format long; disp(pi);    3.14159265358979 >> format short e; disp(pi);    3.1416e+00 >> format long e; disp(pi);      3.141592653589793e+00 >> format short g; disp(pi);        3.1416 >> format long g; disp(pi);           3.14159265358979 >> format hex; disp(pi);    400921fb54442d18 >> format bank; disp(pi);           3.14 >> format +; disp(pi); + >> format rat; disp(pi);    355/113 17.9       more • Matlab allows the user to force paginated output using the more command - very useful for viewing long output from scripts or long help listings more on -              turn paging on. Will present output in “chunks” of a page at a time -              <space-bar> to get another page -              <return key> to get an additional line more off - turn paging off more(n) - set the page size to be n lines 17.10     Files in General • disp and input are associated with the screen and keyboard, respectively - output always to the screen, input always taken from the keyboard • Ideally should also be able to read from and write to files: - important or large input data sets - permanent record of the results of the program • Matlab provides this service through imitation of C’s fopen, fclose, fprintf, & fscanf instructions 17.10.1 Opening & Closing Files fopen    Open a file for reading or writing and provide a descriptor (handle or pointer) for the file.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com file-descriptor=fopen(name,mode); e.g.,                infile=fopen(‘testdata.dat’,’rt’); fclose    Close an opened file.

fclose(file-descriptor); e.g., fclose(infile); 17.11     fprintf • Output arguments to a file using the specified format fprintf(file,format,values) file – file descriptor returned by fopen format – string specifying the format to use for individual arguments values – comma separated list of variables or expressions to be output • Values are matched with format specifications on a one-by-one basis -              implicitly vectorised: will re-use the format specifications for additional values • If no file descriptor supplied goes to screen >> x=5.7; y=19.6; t='text'; >> fprintf('x=%d, y=%f, t=%s\n',x,y,z); x=5.700000e+00, y=19.600000, t=a >> fprintf('x=%d, y=%f, t=%s\n',x,y,t); x=5.700000e+00, y=19.600000, t=text >> fprintf('x=%5.2f or does x=%e or does x=%i\n',x,x,x); x= 5.70 or does x=5.700000e+00 or does x=5.700000e+00 >> fprintf('x=%5.2f or does x=%e or does x=%5.0f\n',x,x,x); x= 5.70 or does x=5.700000e+00 or does x=    6 >> fprintf('%e\t',x,y); 5.700000e+00    1.960000e+01    >> diary off 17.12     Controlling fprintf • Advantages over disp -              exact control over format of output -              vectoring makes tables etc. easy without loops combined = [interval ; population]; disp('Micro Organism Population'); disp('Hour            Population'); fprintf('%d\t%6.0f\n',combined); • Some of the important format/control statements include: Control Function %d          Decimal notation %c          Single character %s          String %e          Scientific notation %f          Floating point notation \t            Insert a tab \n           Insert a newline • Each format specification may have a number inserted between the % sign and the letter designator: -              how much space to consume for output -              for floats can specify both total number of characters and those that follow the decimal point 17.13     fscanf • The input corollary of fprintf is fscanf • General syntax: <variable>=fscanf(file,format,size) file – file descriptor format – as for fprintf size – optional. The number of elements to read. If no size then will consume the entire file.

• Values are matched with format on a one-to-one basis • If no file descriptor is supplied it reads from standard input (the keyboard) • Useful for “sucking in” large data sets, but often load will do the same thing simpler.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com e.g., response = fscanf(‘%s’,1);             % Simpler to use                                                                                                          % input % A file called temperatures.dat holding a % number of temperature values. Open the file % and suck the values (all of them) into a % variable called temps and find their mean.

tempFile = fopen(‘temperatures.dat’,’rt’); temps = fscanf(tempFile,’%f’); fclose(tempFile); fprintf(‘The mean temperature is %4.1f\n’,                               mean(temps)); 17.14     Projectile Example A program to calculate the flight path of a projectile (e.g., mortar shell) using the standard equations of motion.

User will supply initial muzzle velocity and angle of barrel inclination, together with how many “snap-shots” of the shell’s flight are required.

Using the equations of motion and basic geometry we derive: Where                t              is time                g is the acceleration due to gravity                vi is the muzzle velocity                 is the muzzle angle (to the horizon)                ttotal is the total shell flight time                dx is the horizontal distance                dy is the vertical distance 17.15     Projectile Code %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % projectile.m %            A script to calculate the flight path of a %            projectile (e.g., cannonball) using the %            equations of motion, ignoring wind resistance, %            and assuming it was fired on level ground.

%            User supplies: muzzle velocity, angle of barrel %            inclination and the number of "frames" over %            which a snapshot will be given.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com %            This script is an example as part of the Matlab %            lecture in CS1E covering I/O.

% Author: Spike % Date: 16/2/1999 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% gravity = 9.81;                   % Acceleration due to                                                                            % gravity.A constant.