1 / 13

CS122 Engineering Computation Lab Lab 3

CS122 Engineering Computation Lab Lab 3. Bruce Char Department of Computer Science Drexel University Winter 2012. Review of Lab 2 Cycle. Major Lab 2 concepts to remember Use of “while” versus “for” loops – when each is appropriate

inigo
Télécharger la présentation

CS122 Engineering Computation Lab Lab 3

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. CS122 Engineering Computation LabLab 3 Bruce Char Department of Computer Science Drexel University Winter 2012

  2. Review of Lab 2 Cycle • Major Lab 2 concepts to remember • Use of “while” versus “for” loops – when each is appropriate • “if” statement enables program to choose between execution paths • Troubleshooting / debugging • Review the “purple” error messages to understand nature of error (sometimes clear, other times not) • Syntax errors – check to see where cursor is blinking within the code edit region

  3. Administrative Notes • Please contact your individual instructors with questions and problems • CLC (room 147 UC) will be staffed from Monday through Friday (odd – quiz - weeks) – 9 AM to 5 PM • In order to be eligible for a lab completion session, please see you instructor at the end of the lab period • In order to be eligible for a makeup lab session, you must contact your instructor for permission as soon as you miss your regularly scheduled lab

  4. Lab 3 Overview • Based on materials from Chapter 13 and 14 readings • More on user defined functions as represented by Maple proc • We define them and then invoke them to draw things. • We chain functions together to get more complicated drawings. • Using Maple tables to store a collection of data • How to initialize them • How to get a program to enter values into a table • How to use all the values you’ve put into a table in a plot • Multiple assignment • Return multiple proc results as a sequence of variables • Revisit / introduce key plotting concepts • line plots • display feature to enable multiple plots on same grid • Plotting data collected / stored in Maple tables • Plot options – titles, labels, colors

  5. Lab 3 Overview – Part 0 • Part 0.1 – plotting (line and display), proc function • Part 0.2 – introduction to Maple tables and multiple assignments, more on proc usage • Part 0.3 – more on plotting (plot options), procs

  6. Lab 3 Overview – Part 1 • Part 1 – User defined functions that draw things (boxes) • A. - proc to draw rectangular boxes anchored at origin • B. - expand proc from part A. to specify line color and an anchor point other than origin • C. – use of proc developed in B. to draw multiple boxes on same grid • Will be using proc from part B. in Lab 4 as starting point for simulation of a particle bouncing around in a box

  7. Lab 3 Overview – Part 2 • Use a loop and tables to simulate a “time staged” chemical reaction involving 4 chemicals • 2.1 – Calculate the levels of the 4 chemicals as they change over time. Plot the levels of one of the chemicals as it changes over time • Utilizes a proc to encapsulate the simulation code and to pass in the number of time steps as an input parameter • 2.2 – Extend the proc of 2.1 to : • calculate and plot the levels of all 4 chemicals on the same graph • Pass in initial concentration of all 4 reaction components as input parameters • 2.3 – conduct analysis of simulation results from 2.1, 2.2

  8. Lab 3 programming concepts • More about procs • The Maple proc is a user defined function in which: • You can pass parameters into the proc • You can include multiple statements • You can (optionally) return a computed value or series of values • Example • Quadratic := proc(a,b,c) • local x1, x2; • X1 := (-b + sqrt(b^2-4*a*c)) / (2*a); • X2 := (-b - sqrt(b^2-4*a*c)) / (2*a); • return X1, X2; # returns a sequence of numeric results • end proc; • X1solution, X2solution := Quadratic(1, 1, -12); • Note that this example contains a multiple assignment of results

  9. Lab 3 programming concepts • Working with Maple Tables • While a Maple list can hold a series of values, it is not ideal for storing information that is being created dynamically within a loop • Maple tables contain values that all have the same variable name and are differentiated by subscripts • Tables are especially useful in conjunction with loops, where the loop counter variable can be used to represent the subscripts • Working with tables usually requires: • Declaration of the table • Storage of data in the table within a loop • Possible conversion of the table to an equivalent list for use in processes (such as plots) which require lists as input • The example on the next slide illustrates using a table to collect points for subsequent plotting – as in Part 2 of today’s lab

  10. Using Maple Tables to collect data for plotting chemical reaction compositions # Set up initial concentrations A := A0; B := B0; X := X0; Y := Y0; # declare tables indexTab := table(); Atab := table(); for i from 1 to numTimeSteps do newA := A - k1*A*X; … A := newA; indexTab[i] := i; Atab[i] := A; end do: # within Fplot, indexTab and Atab tables are converted to lists display([Fplot(indexTab,Atab,"Green")], title="graph of A", labels=["time", "concentration"]);

  11. Lab 3 programming concepts • A word about time staged simulations • We introduce time staged simulations in the chemical reaction exercise in today’s lab – Part 2 • In a time staged simulation, the loop steps represent time slices • Each iteration of the loop calculates the next generation of values based on correlations using the present generation • In today’s chemical reaction, the concentrations the of 4 reaction components are computed for the next generation (step) from their current values and other coefficients • newA := fn(previousA, B, X, Y) • newB := fn(previousA, B, X, Y) • newX := ………….. • newY := …………..

  12. Lab 3 programming concepts • And finally, some Maple plot features we’ll be using today • Line plotting • Requires with(plottools); • Format  line( [x1, y1], [x2, y2] ) • Display multiple plots on same grid • Requires with(plots); • Format  display( [line([x1,y1], [x2,y2]) , line([x3,y3],[x4,y4])], color=red); • Plot points contained in X and Y coordinate lists • xList := [1, 2, 3, 4, 5]; • yList := [2, 4, 6, 8, 10]; • Plot(xList, yList, style = point, title=“sometitle”, labels=[“x-axis”, “y-axis”]); • Converting tables to lists (plot commands require Maple lists) • xList := convert(xTab, list); • yList := convert(yTab, list);

  13. Course activities for Quiz week (2/20-2/24) • Quiz 3 will be released on Friday (2/17) at 6 PM • Deadline: Thursday (2/23) at 4:30 PM • Makeup quiz – from Friday (2/24) at 9 AM through Sunday (2/26) at 11:00 PM • 30% penalty • Pre-lab 3 quizlet • From Thursday (2/23 – noon) through Monday (2/27 – 8 AM) • Be sure to visit the CLC for quiz assistance

More Related