January 8, 2012

Delphi For Fun Newsletter #62

Best wishes to all for a happy and prosperous new year!

We had a good holiday season.  I now have a new stack of books to work through in the coming months in case real winter ever arrives.  It looks like program production slowed in the past quarter most likely because the programmer (me) is slowing down.  The two posted in December were pretty satisfying though; first, an dragstrip timing tree simulator which drives an external  relay board to operate a physical tree built by one of our viewers.  The second is an earth satellite simulator.  One of the books in my unread stack is "An Introduction to Celestial Mechanics" so I hope to tackle multiple interacting orbital bodies this year. 

In the meantime here are the new posting in the last quarter of 2011.    


October 14, 2011: We're  back home from a short hiatus visiting a grandson at college, Williamsburg Colonial village, Jamestown, Yorktown, and the Virginia Sate Fair.  A Yorktown, I picked up "The Campaign That Won America, The Story of Yorktown" by Burke Davis and I've found it fascinating reading even though there is not an equation or puzzle in it.  The main takeaway for me:  the French played a crucial role in winning our independence from evil old Britain.  I may have to reconsider my opinion of things François.     

I posted another update today to a program included in our Wordstuff program, Unscramble this time.  I added an option to handle cases where, rather than being scrambled, words are "interlaced".  Letters for 2 or 3 words appear in the correct order but interspersed with letters of the other words.   A new checkbox on the Unscramble form indicates that the letters represent interlaced words.   The sample set of 17 letters included on the form represents 3 synonymous words in a puzzle from a recent Mensa Puzzle Calendar page.  I did not successfully identify the words using human brainpower, but the program finds them in several ways in a minute or two.         




October 21, 2011:  Scrambled Letter Blocks was posted today in our Delphi Techniques section.  The puzzle is from the October 17 page of my 2011 Mensa 365 Brain Puzzlers Calendar

"Form six 9-letter words by combining two 3-letter blocks below with each ending already placed in the grid. All blocks will be used. If you do it correctly, one of the vertical columns will spell a bonus word.  Use these groups to complete the words in the grid: AFT, ARC, BET, DEM, ERG, HEN, KEB, ROT, SCO, SNA, UND, YST"


October 30, 2011:  A batch (command line)  version of our Clear Blank Lines utility program was posted today to help a user who needs to run the program repetitively.  The program removes lines from user selected text files which are entirely blank.   Batch files can be a pain in the "you-know-what" to set up but are an convenient way to repetitively run a program without user interaction.     Parameters in this version allow masked searches for files to be processed including ability to search subdirectories, and to make backups of files which are changed.  The download includes sample test files and  a batch file to process them.  

November 10, 2011:  If you are into search algorithms, here's one, Branch and Bound,  which demonstrates "Exhaustive" and "Branch and Bound" search methods for finding the best solution for "Knapsack" problems.  It was adapted with the author's kind permission from the book "Ready-to-Run Delphi 3.0 Algorithms", Rod Stephens, Wiley Computer Publishing. The Knapsack Problem requires that we figuratively fill a knapsack by selecting from a set of items whose weight (or other "cost" measurement) and value (or "profit") are known. The objective is to maximize the value (profit) of the items in the sack without exceeding a predefined weight (cost) limit.  The "Branch and Bound" method  is orders of magnitude faster than Exhaustive  search for large cases.



November 13, 2011:  Another  small feature upgrade for our Brute Force Solver program today.  In Brute Force Version 2.6, you can specify the allowed solution integers as a range ( for example. 1-5 instead of 1,2,3,4,5.    Today's Mensa Calendar Puzzle "Alphametics" problem is also included in the sample problem download files as a test case..  Just enter NOW+NOW+NO=CHOW into the program to find the answer. 

November 30, 2011:  The  Four Fours problem requires that digits 4444 be combined with mathematical operations to form expressions which evaluate to all values from 0 to 100.  I couldn't do it using +,-,*,/,^ operations (other "cheats" are required).  I did generalize the problem so that my Four Fours version does find 4 digit solutions for smaller target ranges or 5 digit solutions for all 101 targets..


December 4, 2011:  The original Drag Strip "Christmas Tree" program simulates the sequenced lights used to control drag race starts.  I recently enhanced the program to drive real lights on a real model tree  using a USB relay board for a drag car owner and enthusiast. .  See  Dragster Tree Relay Version 2 for more details



A satellite with initial altitude of 1000 miles and 15000 mph velocity will circle the earth in 100 minutes at altitudes from 1000 down to 100 miles above surface 

December 18, 2011:  Whew!  It has been a busy month between deer hunting, Christmas preparations, and educating myself about how satellites manage to orbit the earth.   A decent little 4 point buck is in the freezer, the Mission style bookcase for the wife's scrapbooks  finished, and Earth-Sat   Satellite Simulator Version 1  was  posted today. 

Of the three activities, the simulator took the most time by far, but I now have a pretty good handle on how and why satellites manage to stay in the sky.  I'll be checking and cleaning up the documentation in the next  day or two, but I believe the program is in pretty good shape.  

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