Powerstone Program

[Alden Loveshade]

The Powerstone formula in GURPS Magic seems very sensible and there is a handy chart giving the typical price for many powerstones. But still, doing the formula for several stones with capacities that don't match the ones in the table takes time and, if you're like me, can involve mistakes.

I admit I only did a cursory search, but does anyone know an online or downloadable program for figuring typical powerstone costs? I'm thinking of something where you type in the capacity and it spits out a price. I could write such a program myself (it would be very basic), but if I’m too lazy to use the formula….

[Diomedes]

Originally Posted by Alden_Loveshade

The Powerstone formula in GURPS Magic seems very sensible and there is a handy chart giving the typical price for many powerstones. But still, doing the formula for several stones with capacities that don't match the ones in the table takes time and, if you're like me, can involve mistakes.

I admit I only did a cursory search, but does anyone know an online or downloadable program for figuring typical powerstone costs? I'm thinking of something where you type in the capacity and it spits out a price. I could write such a program myself (it would be very basic), but if I’m too lazy to use the formula….

I turned it into an Excel spreadsheet a while back.

[munin]

Originally Posted by Alden_Loveshade

... I'm thinking of something where you type in the capacity and it spits out a price...

Try making a favorite/bookmark out of the following as the address, then load the favorite/bookmark. It should ask you for a powerstone capacity, then bring up the answer on google.

javascript:c=prompt('Powerstone%20Capacity:','');if(c){document.location='http://www.google.com/search?q=(10*'+c+'^2%252B40*'+c+')*(54%2F53)^'+c+'%252B20*'+c};

[Alden Loveshade]

Thanks for the suggestions. Ironically, shortly after I asked the question I thought of another way to do it, although this might be a bit more work than your suggestions.

Enchanted Powerstone cost

Save the equation for the powerstone cost in a word processing program: ((10 * P^2 + 40 * P)/(53/54)^P) + (20 * P)

Replace All the P's with the capacity (for a 100 point powerstone P = 100; 157 point powerstone P = 157)

Then copy and paste it into an online scientific calculator such as found at http://www.ecalc.com/

Unenchanted Powerstone cost

To learn the cost of an unenchanted "stone" that would work efficiently to be enchanted to P capacity, do the same thing with

10 * P^2 + (40 * P)

[Akicita]

RPK hosts a spreadsheet on his MyGURPS site that covers both powerstones and other enchantments. It's designed to stay close to RAW while allowing the user to vary the base assumptions to personal taste.

Edit: Oops. Forget I said anything; it doesn't seem to be there. Will post again if I figure out where it is. AH, here we go:


http://www.mygurps.com/pics/Pstone_rev2010.xls

[Alden Loveshade]

Originally Posted by Akicita

RPK hosts a spreadsheet on his MyGURPS site that covers both powerstones and other enchantments. It's designed to stay close to RAW while allowing the user to vary the base assumptions to personal taste.

Edit: Oops. Forget I said anything; it doesn't seem to be there. Will post again if I figure out where it is. AH, here we go:


http://www.mygurps.com/pics/Pstone_rev2010.xls

Thanks for the link! It looks useful for other things as well.

[Anthony]

The powerstone formula in vanilla GURPS is actually somewhat problematic because it makes no attempt to address the issue of quirks; the spreadsheet mentioned above seems to make some attempts at fixing the issues, though I have quibbles with details (notably, he leaves out the entire issue of powerstones created with cheap materials, and they actually matter a lot. I did some of my own analysis here).

[ClayDowling]

Originally Posted by Alden_Loveshade

Save the equation for the powerstone cost in a word processing program: ((10 * P^2 + 40 * P)/(53/54)^P) + (20 * P)

As a programmer, this makes me cry. I've written code and provided an osx binary to calculate the value from the provided formula:

http://www.obrienscafe.com/node/4969

[BaHalus]

How I use this last thing?

[Anthony]

Originally Posted by ClayDowling

As a programmer, this makes me cry. I've written code and provided an osx binary to calculate the value from the provided formula:

http://www.obrienscafe.com/node/4969

Um. Well, the provided formula is wrong, which might be why some people go through complicated calculations. That formula (which ignores quirks) should be (60*p+10*p^2) *(54/53)^p, since it's improperly pricing casting cost as written, and can in fact be entered into a spreadsheet in that form if you replace p with the name of the cell containing p.