Problem Sets

MIT 6.001, Fall 1997

Problem Sets

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Problem Set #9
First-order Tail-recursive Evaluator for Scheme (This pset was NOT USED; it's here for the record.)
ps9.ps,
ps9.tex,
tr-flatten.scm,
test.scm,
fotr-evl.scm,
fotrinit.scm,
derived.scm.
Problem Set #8
- PS8 Solutions (postscript)
- PS8 Notes:
  - EXERCISE 2. Feel free to use lazy-memo parameters if you prefer.
  - IGNORE EXERCISE 7B. (Under the "fresh variable" assumption, nothing goes wrong.)
  - The printed version of EVDATA.SCM attached to the PS8 handout was not the current one. In particular, it doesn't have the definition and installation of the MPAIR? procedure needed for Exercise 4. The online copies of EVDATA.SCM do have the correct information.
- PS8 Text in Postscript (Revised Exercise 7, 11/13, 4pm)
- PS8 LaTeX Source
- Zip of PS8 Code contains the following code files:
Problem Set #7
- PS7 Solutions (postscript)
- PS7 Text in Postscript
- PS7 LaTeX Source
- Zip file of PS7 Code contains the following code files with some names shortened to comply with older systems (old names in parentheses):
Problem Set #6
- PS6 Solutions(postscript)
- PS6 Notes:
  - Do not use the adjacency list in the file urls.scm! Use instead 6001rprt.scm.
  - p.5: The sentence before the depth-first-search procedure should be replaced with:
    "Here is the version of depth-first search which will search an arbitrary directed graph, starting from a node with a given name, until it finds a satisfactory node. The value of parameter found-it? is intended to be a predicate which determines whether a visited node is satisfactory."
  - p.7, 3 lines before breadth-first-search-path-back, change "depth-first" to "breadth-first": it is breadth-first search that yields shortest paths.
  - Exercise 9: the two mentions of a linked procedure should be replaced by "linkup".
- PS6 Text in Postscript (revised 10/27)
- PS6 LaTeX Source
- Zip file of PS6 Code Contains the following code files:
Problem Set #5
- PS5 Solutions (html)
- PS5 Notes: Minor corrections to PS5 are noted below. These are incorporated in PS5 Text (postscript, revised 10/15), but if you have the printed version distributed on 10/14 and note the corrections below, there is no need to get the revised version.
  - Exercise 4: In addition to modifying dict-merge, you should also modify tensor so it filters out "failed" dictionaries returned by dict-merge. You should include results of your modified procedures applied to test examples involving repeated question-mark variables only. Your code probably will not work on repeated tilde-variables, for reasons explained in the footnote to Exercise 4 in PS5 Text (postscript, revised 10/15).
  - Exercise 8. In case it wasn't clear: the all-final-forms procedure is supposed to return a list of all final forms resulting from repeatedly applying every rule in every order to every subdatum of the datum.
  - p.4, l.6: " " should be "~".
  - p.5, l. -12: the second occurrence of '(~a ~b ?c ~d) should be '(~a - ~b - ?c - ~d)
  - p.5, l.-14: Note that the procedure all-rule-applications is not defined in the code files; writing its definition is Exercise 7.
- PS5 Text in Postscript (revised 10/15)
- PS5 LaTeX Source
- Zip file of PS5 Code. Contains the following files:
Problem Set #4
- PS4 Solution in Postscript
- PS4 Notes: Replace any ps4.scm you downloaded before 9:40am Oct 10 with this one: ps4.scm. There were a couple of typos (an extra paren in the def of evaluate, mispelled wscdI) in the earlier ps4.scm which have been fixed in the current one. Also note that the printed PS4 text distributed Tuesday, 7 October, has an improperly quoted variable ATHLETES, repaired in the postscript version:
- PS4 Text in Postscript
- Zip file of PS4 code. Includes the file ps4.scm
Problem Set #3
- PS3 Solutions, without figures (postscript)
- PS3 in HTML, (missing some pictures)
- PS3 Text in Postscript (minor typos corrected 9/28)
- Zip file of PS3 code. Includes the following four files:
- PS3 Notes:
  - Because there is no Scheme standard for graphical interfaces, the code for this problem set is not portable and will work only in MIT Scheme. Our apologies to Macintosh and EdScheme users.
  - To print graphics
    - from Windows:
      (graphics-operation g1 'save-bitmap "c:/temp/foo.bmp")
      Now print the bitmap using your favorite software, for example the Paintbrush program.
    - on Athena:
      Use the command
      lprpic -P<Printer-Name>
      Your mouse cursor will temporarily become a +, and then you can click on any window to print it.
      To save picture files (in postscript)
      xwd | xpr -device ps -portrait > <filename>.ps
      (Yes, the first " > " should actually be typed.) Be warned that picture files are LARGE.
Problem Set #2
- PS2 Solutions (postscript)
- PS2 Text in HTML (missing an equation)
- PS2 Text in Postscript
- There are no code files for PS2
- PS2 Notes:
  Lab Exercise 2.7, line 3: missing X. Expression should be (sine-taylor X n). Corrected in files above.
Problem Set #1
- Problem Set Solutions in Postscript
- Problem Set Text in HTML
- Problem Set Text in Postscript
- Problem Set Code:
  - Zip file of PS1 code. Includes the following four files:
- Problem Set Notes:
  Revised wording in 6A:
  ``You should have noticed that the implacable searcher does well against the random-answer hider. A more plausible random-location-hider picks a location at random in the current interval and answers as though it were at that location. While the random-answer hider answers "higher" with probability one half, the random location hider is more likely to answer "higher" when the interval above the split point is larger than the interval below.''
  Typo in Exercise 5: "naive-searcher" should be "random-searcher" This is corrected in the ps file above.
  In a number of problems we have left it ambiguous whether the range (Ex. from 0 -> 30) includes the high value (30), and therefore how many elements there are (30, or 31). Make a choice that makes the most sense to you and tell us which one you chose.
Problem Set #0
- Problem Set Text in HTML
- Problem Set Text in Postscript
- Problem Set Code: debug-code.scm
  - Zip file of PS0 code. Includes:
- Problem Set Notes:
  This version has been updated since it was distributed in recitation on Sept.3. The main change is that use of lambda has been eliminated. Lambda will be explained next week. Also, the erroneous expression which was supposed to activate the debugger has been revised to really do so.