1 / 15

Engr 0012 (04-1) LecNotes 04-01

script organization. General organization for scripts. 1. Header. 2. Variable dictionary. 3. Constant definitions. 4. Input data/independent variable/parameter values. 5. Computations. 6. Output results/dependent variable values. ex: wkshp5_ac1.m. Engr 0012 (04-1) LecNotes 04-01.

matty
Télécharger la présentation

Engr 0012 (04-1) LecNotes 04-01

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. script organization General organization for scripts 1. Header 2. Variable dictionary 3. Constant definitions 4. Input data/independent variable/parameter values 5. Computations 6. Output results/dependent variable values ex: wkshp5_ac1.m Engr 0012 (04-1) LecNotes 04-01

  2. introduction to functions functions are the “workhorse” of computing script/function comparison Show program logic answer “what” questions Show program details answer “how” questions ex: wkshp7_soln.m Engr 0012 (04-1) LecNotes 04-02

  3. generic function “definition” function [results list] = fcn_name(needs list) % % function purpose (i.e., fcn_name does ???) % needs: 1st variable in needs list % 2nd variable in needs list % results: 1st variable in results list % 2nd variable in results list % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % variable dictionary % MATLAB statements (w/comments) that fulfill purpose Engr 0012 (04-1) LecNotes 04-03

  4. 1. functions that need nothing and return a value(s) defn: function [rho, g, height, pout] = wkshp7_getdata( ) use: [rho, g, height, pout] = wkshp7_getdata; 2. functions that return nothing and need a value(s) defn: function [] = wkshp7_results(rho,g,height,pout,pabs_b) use: wkshp7_results(rho, g, height, pout, pabs_b) 3. functions that need and return a value(s) defn: defn: function [] = wkshp7_header( ) function [pabs_b] = wkshp7_pbot(rho,g,height,pout) use: use: 4. functions that need and return nothing (rare) wkshp7_header pabs_b = wkshp7_pbot(rho, g, height, pout) four types of functions Engr 0012 (04-1) LecNotes 04-04

  5. constants have no values needed to calculate ==> needs list is “empty” ==> results list has a variable name must have one assignment statement for each name in results list function that provides a constant value function [ConvFac] = BTU_to_J( ); % Conversion factor for BTU to joules % needs: % results: ConvFac conversion factor, J/BTU % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % % variable dictionary % ConvFac conversion factor BTU to J, J/BTU ConvFac = 1055.0; Engr 0012 (04-1) LecNotes 04-05

  6. using function that provides a constant value copyBTU_to_J.m from get to temp directory » 2 ans = 2 » BTU_to_J ans = 1055 » b = a*BTU_to_J b = 2110 » help BTU_to_J Engr 0012 (04-1) LecNotes 04-06

  7. ==> needs list is “empty” ==> results list has at least one name function that returns a single value but needs nothing function [amount] = getdollars( ); % get $ amount for financial calculations % needs: % results: amount - amount input, $ % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % % variable dictionary % amount amount input, $ amount = input('\nEnter principal amount ==> '); Engr 0012 (04-1) LecNotes 04-07

  8. using function that returns a single value copygetdollars.m from get to temp directory » getdollars ans = 3 » dollars = getdollars dollars = 4 » principal = getdollars; » help getdollars Engr 0012 (04-1) LecNotes 04-08

  9. ==> needs list is “empty” ==> results list has more than one name function that returns more than one value but needs nothing function [time1, time2] = gettime( ); % get start and stop times for race % needs: % results: time1 start time, s % time2 end time, s % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % variable dictionary % time1 start time, s % time2 end time, s time1 = input('\nEnter start time in sec ==> '); time2 = input('\nEnter end time in sec ==> '); Engr 0012 (04-1) LecNotes 04-09

  10. using function that returns more than one value but needs nothing copygettime.m from get to temp directory » gettime ans = 4 only first value entered displays as default » [start,stop] = gettime start = 1 stop = 4 values assigned in order » [start,stop] = gettime; » help gettime Engr 0012 (04-1) LecNotes 04-10

  11. ==> needs list has at least one name ==> results list has at least one name function that needs and returns values function [celsius] = FtoC(fahr); % convert temp in F to C % needs: fahr temp in F, F % results: celsius temp in C, C % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % variable dictionary % fahr temp in F, F % celsius temp in C, C celsius = 5.0*(fahr-32.0)/9.0; Engr 0012 (04-1) LecNotes 04-11

  12. » BoilF = 212; » FtoC(BoilF) using function that needs and returns values copyFtoC.m from get to temp directory » FtoC ??? Input argument 'fahr' is undefined. Error in ==> D:\Workarea\engr classes\e12(03-1)\MATLAB -\FtoC.m On line 11 ==> celsius = 5.0*(fahr-32.0)/9.0; » FtoC(212) can provide “value” as a number ans = 100 ans = 100 can provide “value” as a variable name Engr 0012 (04-1) LecNotes 04-12

  13. ==> needs list has at least one name ==> results list no names function that needs values but returns nothing function [] = conv_results(fahr, celsius); % display temperature conversion, F to C % needs: fahr temp in F, F % celsius temp in C, C % results: % % JF Patzer % Engr 0012 % Fall Term, 2003 (04-1) % Mon 8 Sep 2003 % variable dictionary % fahr temp in F, F % celsius temp in C, C fprintf( '\n%.2f F is %.2f C', fahr, celsius ); Engr 0012 (04-1) LecNotes 04-13

  14. can use values can use variable names using function that needs values but returns nothing copyconv_results.m from get to temp directory » conv_results(123,3454) 123.00 F is 3454.00 C » conv_results(boilF,boilC) 32.00 F is 0.00 C Engr 0012 (04-1) LecNotes 04-14

  15. Class Activities 1. Workshop 06 - Scripts and Workspace 2. Workshop 07 - Intro to Functions Turn in at start of next class (Wednesday 10 September) MATLAB Workshop 07: Exercise 3. paper copy of script and screen printout of script working with h = 12.3 cm Engr 0012 (04-1) LecNotes 04-15

More Related