April 25, 2016:
In this No Close Neighbors Mensa
Calendar puzzle solver, the user or the program must insert the letters A
through J, one per square, so that no two letters in alphabetical order are in
squares that touch in any way, even at the corners. Three letters have
been placed to get started. In addition, the program has a "Build"
mode allowing users to define more puzzles. The two known "ready to build"
examples are included.
April 15, 2016:
One more feature was to our Latitude/Longitude distance calculator program today. When calculating an end point from a start point, direction and distance, Latitude Longitude Distance Version 3.2 lets the user to choose between Great Circle and Rhumb Line travel . Great Circle travel is the shortest route between two points, but requires continuously adjusting the direction of travel. The new Rhumb Line option allows one to travel at a constant bearing from where you are to where you want go or to explore what lies at a a given direction at a given distance. Just know that constant bearing (Rhumb line) travel is the simplest, but not the shortest way to get there.
April 3, 2016:
is a program which looks for optimal ways to cut a list of rectangular parts
from a list of available supply pieces. The program is popular
but too complex to work on for fun these days, so until I get around to create a
commercial version, I code bug fixes only. Finally, after two years,
another bug was discovered and fixed. When printing layout diagrams for a
solution with no other lists selected, the layout printing was incorrect.
Only the final page of supply piece diagrams would be printed. It was
fixed to day with Cutlist Version 4.03.
The layout diagram page titles now also show which solution is being printed.
March 25, 2016: I first posted a program to calculate the distance between two points on the earth's surface in 2004. Distance is understood to be the shortest distance which is slightly mind-blowing when the Great Circle Route says that if you fly from New York to London, you must fly north over Newfoundland first ! Except at the equator, the shortest path to a location directly East of you involves starting out in a Northerly or Southerly (Southern hemisphere) direction and arrive traveling slightly South (or North).
Latitude Longiitude Distance Version 3.0 posted today is in response to a request from a blind(!) Delphi programmer working on a program that will allow other blind people to follow Great Circle routes from point to point and "explore" where they travel along the way. To do this Stefan needed a way to plot the bearings at steps along route. Version 3.0 does that by displaying points traversed when moving from given a starting bearing and a total distance. User can select 1, 10, or 100 steps and see the coordinates and the new bearings at each step along the way. I wish him the best in adapting this code to his application.
In the process, I uncovered an occasional "final bearing" error in my previous implementation of the algorithm which finds points from distances. I made, and now use, a conversion of a National Geographic Information System (NGIS) Fortran program which is not only simpler, but eliminates the error.
March 18, 2016:
An intermediate level exercise posted in our
Delphi_Techniques code section based on a a user's request for help drawing doors subdivided with one or more vertical frames separated
and divided by mullions of a given width and position. Find out more
and download source and executable file at
The original demo illustrating the Dijkstra algorithm (method) for finding
shortest paths, calculated the shortest path from Node 1 to node 10 of a
sample graph using random weights (distances) from node to node. The search
was one-way (i.e. could only move to higher numbered nodes), but a programmer recently modified the program to search from
node 2 to node 10. A problem surfaced when the shortest path happened to be
2-1-3-7-10 which required traveling backwards through node 1. Shortest
Path Demo Version 2.0 posted today incorporates two-way searching
and allows users to specify both the start node and the goal node.
February 21, 2016: For programmers - I wrote a Countdown timer control several years ago because I needed one for a puzzle program with a time limit. I later modified it to also "count up" in order to time long-running programs. I just added an "TimerPop" event exit to let the calling program check once per second to take any desired action based on run time or time remaining. The control is included with Countdown Demo Version 2.1 which now tests the feature by beeping once per minute.
February 20, 2016:
Coal to Diamonds is a wicked hard puzzle to solve. "Coal"
is changed to "Diamond" in a thee step process. Each click of a cell of a 3x3
grid advances all elements in that row and column by one step. A high school student learning Java (L)
had a version of this puzzle in a coding competition except the goal was all
coal instead of all diamonds ([000 000 000] instead of [333 333
333]). I cleaned up some of the screen formats and text and added
user control of the goal state in Coal to
Diamonds Version 2.0.
February 14, 2016: Aussies always like to break the mold and do things differently. They did it again with Daylight Saving Time (DST) calculations: Time Zone Demo Version 2.1 fixes two problems uncovered by a Brisbane programmer when he reported the demo program crashing. Problems when DST crosses a year boundary or regions with no DST at all (like Brisbane!) should now be fixed. The program now reports correct end dates for Southern Hemisphere regions and "no DST for this location" instead of crashing when there is none. Changes have not been tested, but someone down under will surely let me know if the problems still existJ.
February 10, 2016:
Sound Generator is a program which can create complex tones by combining
multiple frequencies. Sound Generator
Version 3.0 uploaded today adds an option to easily create the
"Touch-Tone" sounds used in modern landline telephone connecting protocols.
The technology referred to as Dual Tone Multi-Frequency, DTMF, encoding. It
combines two frequencies to create 16 distinct tones for digits '0'
through '9', letters 'A' through 'D', plus '*' and '#'
special characters as illustrated in this grid at right. Multiple
characters in a string may be played and saved in a "wave" audio format
file. This may prove useful in a future program decoding audio tones back
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