sympy/sympy_gamma — pull request #4 by lidavidm (2012-10-06 18:30:56+00:00)
Title: Saved queries, example queries, more result sets

Changes (not quite ready yet):

- You can log in to save your queries.
- More result types
- Examples displayed on front page
- Function plotting uses adaptive sampling (as @catchmrbharath pointed out)
- Visiting and using the site in Chrome should create a search provider for the omnibox
- Favicon and logo added

Examples:

- See front page (http://sympy-gamma-li.appspot.com)

(The arrows there are a little quirky, I'll fix that)

Result Types:

- Derivatives, series, `solve`, `solve_poly_system`
- Simply evaluated (latter two have nicer formatting)
- `series` allows you to specify `x0` and `n`

I'm putting this here for feedback on the examples - are there any other examples you would like to see added?

Also as @Krastanov mentioned I would like to use interpolation to get displayed function values on the plot. It only seems to give 1 significant digit with `0.5 * (f(x_1) + f(x_2))` where x_1 and x_2 are the two closest x_values, so perhaps it would be a fallback for when the JS generation doesn't work.

The adaptive sampling samples points randomly, so the y-range can vary for the same plot between different runs when there are asymptotes (e.g. http://sympy-gamma-li.appspot.com/input/?i=tan%281%2Fx%29). What I am doing is if the max y-value is more than 10 times the mean of the positive y values, I cut off the graph at the mean of the positive y values (and the equivalent for min-y/negative y). This tends to make graphs like [`1/x`](http://sympy-gamma-li.appspot.com/input/?i=1%2Fx) strange, however, as the y-axis will be scaled differently each time. Also, the position of the x-axis can vary now, which saves space on graphs like [`exp(x)`](http://sympy-gamma-li.appspot.com/input/?i=exp%28x%29).