Curiosities of a Rambling Mind

The Latest Addition

June 22nd, 2010 Posted in Amortization Calculator | No Comments »

Over the years, a lot of people have asked for calculator features like occasional extra principal reduction payments, tracking fees or late charges, summary of interest over a fiscal year. My pat response is “this kind of thing needs a spreadsheet or special-purpose software.”

Well, I’ve taken a little time to work up a basic amortization spreadsheet. It doesn’t have all the calculation options that the web calculator provides (it only calculates the payment, for example), but the amortization schedule it produces will allow one to track extra payments and fees, to include payments for insurance and taxes, and it provides a nice fiscal year summary of interest paid.

It took a few days of playing around with Excel to get it working mostly right, and it’s free for you to download and try, if you’re into that kind of thing. Maybe it will give you some ideas about how to build your own custom spreadsheet. But of course, use at your own risk! Please don’t base any high-finance decisions on the spreadsheet’s results until you’ve verified that it’s doing everything correctly. Like the web calculator, I consider this a planning tool only!

If you want to give it a shot, here’s a link to the spreadsheet. Enjoy!

Pushing the Limits

June 14th, 2010 Posted in Amortization Calculator | No Comments »

I’ve made a few more improvements to the calculator today. Since I added some comma separators to the output to improve the readability of larger numbers, I thought I should do something about the upper bound of the calculator. Before today, the calculator couldn’t amortize amounts larger than about 21.4million. This upper bound was imposed by the computer’s native word size and how I chose to round values to the nearest whole penny. By changing the rounding procedure, I have boosted that upper bound to under 10billion. Above this value, the calculator will silently start to lose resolution at the low end, but amortizing values in the 100s of millions should be possible now.

Identifying the cross-over point

June 12th, 2010 Posted in Amortization Calculator | No Comments »

I just can’t help myself: when I start to tweak things, I start coming up with more ideas for making things a little better or easier. Nothing dramatic, just little things.

Today’s idea was to make it easy to identify that point in the amortization schedule when the principal component of a payment first exceeds the interest component of a payment. Let’s call that the cross-over point. If you run an amortization schedule now, the cross-over point is highlighted in green. There may be schedules without a cross-over point (usually shorter term loans), in which case there’s no special highlighting.

Who knows what might come next, now that I’ve started tweaking. :-)

Small Improvements

June 11th, 2010 Posted in Amortization Calculator | 1 Comment »

It’s been a while since I’ve made any improvements to the calculator, but today I finished a few cosmetic upgrades. The Summary section has some nicer layout and formatting, and the addition of comma-separators should make larger numbers easier to read.

Even more math…

October 2nd, 2009 Posted in Amortization Calculator | No Comments »

Hi, folks. It has been quite a while since I’ve made any substantial additions to the site. I just added a new document with some new formulas for directly calculating the interest portion of any payment, and for calculating the total interest paid so far. If you’re into math, you might find the Interest Recurrence document mildly useful.

A little Halloween treat

October 30th, 2008 Posted in Amortization Calculator | 3 Comments »

I added a little Halloween decoration to the calculator page, for some holiday variety. Thanks to Don Barnett for the cool pumpkin background.

Calculator Printing and Display tweaks

October 17th, 2008 Posted in Amortization Calculator | 1 Comment »

I’ve made some slight modifications to the schedule display: alternating rows of the table now have color bands to help identify rows more easily. In the process, I was also able to reduce (slightly) the amount of HTML that’s generated, allowing the schedule to download and render more quickly (though this is hardly an issue for most of us these days).

For people generating hard copies, I made some very minor tweaks as well. I don’t know if it makes things any better or not.

We get the government we deserve

September 8th, 2008 Posted in Politics | 3 Comments »

This morning I received a note passed along from a friend with a list of all the books that Sarah Palin, our newly appointed candidate for Vice-President, had allegedly proposed to ban from her local library while she was Mayor of Wasilla, Alaska. I couldn’t believe some of the entries on the list, so I did some further digging.

It turns out that Sarah Palin did not actually put forth a list of books she wanted banned, but had merely inquired of the local librarian about how one might get books banned. After the librarian resisted, Palin tried to have the librarian fired. This is plenty enough egregious for me: I don’t need a list of books. However, I also detest that someone felt the need to somehow make the case even stronger by inventing a list. Haven’t we learned anything from the first OJ trial? Planting evidence can only backfire.

After years of distortions, half-truths, deceptions, and outright lies, this behavior has come to be expected from those seeking positions of power in this country. And the press too often has not even noticed. And We, The People, have let all of them get away with it.

If we are truly intent on saving our nation from what appears to be an inevitable decline, we need to fight for those things which are important to us. We have allowed ourselves to be deceived because it’s easier than being vigilant. We must educate ourselves, seek out the truth, dig, and hold accountable those who lie to us. We need not believe that we cannot change the system: we’re not yet too far gone.

But if we do not remain alert, if we accept without question the constant stream of distortions that are spewed at us, if we do not engage our own critical thinking in selecting those who would lead us, then we deserve the bloated, dysfunctional, self-serving government that We, The People, have put into power.

Science, Religion and Politics

September 4th, 2008 Posted in Blather, Politics | 1 Comment »

I am a person of Faith: I believe in a Divine Creative Force that put this universe together, and that we human beings are an intentional component of that creation. I am also a person of science that trusts the process by which we discover how our universe works. I live comfortably with both, and so I am often surprised and dismayed by what some would put forth as a fundamental conflict between two disparate world views—one held by religious folks, the other held by scientists.

I hesitate to call myself a scientist since I’m not actively involved in research, but I work with scientists, and I have a well-rounded (if perhaps superficial) educational background in several fields of scientific endeavor. I find that most general media sources (e.g., newspapers, nightly news), at least in the US, are quite unreliable in the reporting of science-based news. The public-at-large seems to be increasingly ignorant of the fundamental scientific process and its results, which may contribute to the perceived friction between hard-line religious groups and hard-core scientists. The increasing politicization over matters of scientific inquiry by the current presidential administration has exacerbated the problem by blurring the lines between ascertainable facts, belief structures, and public policy.

I believe that where some religious groups have got it wrong is that science is not a belief system: it is a method of inquiry, a means of discerning how the universe works, through observation and experimentation. Occasionally science discovers a property of the universe which comes into conflict with the tenets of a belief system. Inflexible belief systems resist integrating these new concepts into their structures, but eventually they’re forced to find a way to accommodate them—usually after much wailing and gnashing of teeth. If belief systems cannot adapt to new discoveries about how the universe works, they risk becoming irrelevant, out of touch with the world around them.

Where I think some scientists have got it wrong is that science is not capable of answering every question: it’s much better at determining “how” than “why” (e.g., how does my body turn the lunch I just ate into the energy to type this blather? vs. why am I on this planet typing this blather?); as the scientific method depends on repeatability and observation for results, there are limits to what it can ascertain (i.e., things that are not observable or repeatable are beyond the grasp of rigorous scientific proof). Early in the 20th century, both physics and mathematics discovered a few of their own limitations, e.g., the Heisenberg Uncertainty Principle and the Gödel Incompleteness Theorem, respectively. And while it is true that science strives to be objective, it is also true that scientists have biases themselves: where data and observations are insufficient, gaps in theories may be filled in by intuition or past experience. However, theory must ultimately be supported by observation, or do better at predicting new behavior, in order to be accepted by a consensus of others in one’s field.

Where politicians seem to get it wrong is in choosing sides in scientific debates or distorting the scientific arguments for political purposes. Granted, a politician’s job is to take action, sometimes with incomplete information; but when more complete data come to light, it may become necessary to revise one’s opinions and theories, and new or different action may be required. The best leaders are those that make decisions based on the best data available, navigating uncertainty or confliciting information using intuition and/or past experience. If better intelligence comes along, then for all our sakes, PLEASE take corrective action. It should be dangerous business to stake one’s political career on the ever-shifting sands of unresolved scientific understanding. I find it reprehensible to distort or divert the search for scientific truth. To do so nullifies any value science may have for society because its results can no longer be trusted.

Beliefs are a choice. I choose to believe in a Deity in spite of what some would call a lack of direct evidence. This doesn’t make me unscientific (but I would be unscientific if I held beliefs that are contrary to direct evidence). But math and science never start with “nothing”: every proof or theory begins with a set of assumptions or starting conditions. We may each choose whether or not God may be a starting condition in our lives, and we should all be allowed to amend our own personal theories as we continue to live and collect new data.

Let us strive not to conform Truth to our will. Instead, let us be shaped by Truth as we continue to find its facets revealed to us. This is the more difficult, but ultimately more rewarding journey. Or so I believe.

At the Start of a New Year

August 19th, 2008 Posted in Blather | 2 Comments »

January 1st has never felt like a beginning to me. Sure, the number on the calendar changes, but the real start of things happens around the end of August/beginning of September. This is when school starts, and this is what I consider the real beginning of the year. Of course the “school year” is an anachronism for most of us in the U.S.: there are so few of us tied to the notion of harvest season, after all. But summer vacation and “school days” are now cultural icons—part of the natural rhythm of our lives.

Public schools in my county went back into session this week, and my university starts classes next week. The college students have already begun their annual migration back to campus, and the roads are busy with vehicles and U-Hauls crammed full of life’s ammenities. I haven’t been a student for some time now, but the sight of kids toting boxes and hoisting laundry baskets laden with clean clothes takes me right back to my own first arrival on campus, my first dorm room, my first Rush Week frat party.

So even though the lazy days of summer are drawing to an end, and life with all its regularly-scheduled activities is about to spin up to full speed again, and though I’m not quite ready for it all… I can’t help it: I’m still a little bit excited, even giddy. There’s a whole new adventure about to begin.

Happy New Year, everyone!