Dennis' Daze

I have made one output file available

dennis — Tue, 15 May 2012 17:00:46 +0000

See sample output file. Maple also echos the program.

More test results and source code available (differential equations program)

dennis — Tue, 15 May 2012 07:48:47 +0000

Test results at test results
Source code at Source code tar file
The program is in Ruby and generates a Maple program. I have only used it under Linux and it uses a shell script as well.

Test Results Update

dennis — Sun, 13 May 2012 22:56:10 +0000

A summary of my testing is at testrecords There were a few typos yesterday – hopefully they have all been corrected. The test files were OK The error was just in copying them into the table of results. I think at one time I was getting better results for the orders of poles. Also I need to work on multiple equations.

Differential Equation Test Results

dennis — Sun, 13 May 2012 05:40:42 +0000

See Differential Equation Test Result Table

Much more progress on differential equations

dennis — Sat, 12 May 2012 03:28:02 +0000

I have had 1st order equations working for a while, except when I broke things trying to fix other things. One thing I had trouble with was higher order equations. Now that is fixed. Also then there were higher order equations with derivatives on the right hand side. Now that is fixed also. Perhaps, I should digress. Although the program is designed to solve multiple ordinary differential equations, I am only working on single equations now. The highest order derivative is solved for (on the left hand side). The rest is on the right hand side. The program is written in Ruby and generates a Maple program. It is written to be able to also generate Maxima or Ruby. But I am only debugging Maple right now. After some more testing I expect to put it on SourceForge. Also I have also discovered that rounding error is overwhelming the truncation error, which should not have been such a big surprise. I have mostly been testing using Maple set to use 50 Digits and 30 Taylor series terms, but I am only getting about 16 digit accuracy. I remember at the University of Nerbraska, Lincoln when I was first introduced to the Long Taylor Series method by Professor Y. F. Chang, I estimated there would be a large round off error. This was 1977. Professor George Corliss thought the actual error would not actually be so large, or so I remember. Another Professor Lipsky thought the error would be a problem, or so, again, I remember. I have also been working on a Arbitrary Precision Floating Point library for Ruby, which tracks the maximum error possible using differentials. Although very slow, if it works, one could guarantee a certain accuracy. Also, I have such difficulty working things out that I sometimes doubt if I could pass freshman calculus again.

More progress on differential equations

dennis — Mon, 30 Apr 2012 23:49:41 +0000

I’ve been working hard on my differential equation program. Most of the problems (locating poles) resulted from various sorts of Maple bugs I didn’t know were possible. I don’t mean bugs in Maple itself, but rather sorts of things you can do wrong in Maple – and the sorts of results you get. I have solved all the problems I have been working on, but there are more sorts of equations it is intended to solve and I have done enough testing to know there are more problems, but I will let them wait till tomorrow. I have not got much reading done the last few days.

Progress on differential equations

dennis — Sun, 29 Apr 2012 09:31:17 +0000

I fixed a couple things – hard debugging. Basic functions OK now, except I suspect more work will be needed on log and arctan. Also locating poles is not working yet. It was debugging it that led to these other … Continue reading →

My Studies

dennis — Thu, 26 Apr 2012 02:33:44 +0000

I’ve revised my study plan. See my reading. I’ve postponed (at least) the most difficult items. I was finding them too difficult. Logic will be a lower priority. My new years resolution was to try to sleep more. I have been. It seems to take me longer to wake up and I feel irritable for a while after getting up. Also I am dreaming more. I’ve also noticed my reading seems more interesting. I am now sleeping 7-8 hours a night instead of 5-6.

Back to my diffeq program

dennis — Wed, 11 Apr 2012 00:19:47 +0000

I’m back at it. I miss programming. I’ve narrowed down where the problem is in locating singularities.

Confusing fiction with reality?

dennis — Tue, 10 Apr 2012 09:21:21 +0000

I’m reading Unafraid: A Novel of the Possible, by Jeff Golden. It is fun, and as I don’t need to remember it as fact, the reading is faster. But I am afraid I will confuse fiction with fact.