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2015-04-19 01:46:47 +0100 commented answer IPython/Jupyter extensions

No problem Dr. Stein, this is understandably low on the priority list, especially since there are available solutions in the Notebook already. I'll just switch to those for now. Thanks for responding! If I knew how to implement this I would just do it, but I'm having trouble figuring out how to contribute to the Sage project. This is a huge and very appreciated undertaking, though, keep up the good work.

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2015-04-18 08:29:48 +0100 asked a question IPython/Jupyter extensions

I would like to be able to print code objects in a markdown cell without having to completely regenerate them in markdown code or copy/paste values. Would it be possible to install the IPython notebook extensions on the Sage Math Cloud?

I've made a public notebook here so that anyone can see exactly what my problem is. It's a fairly thorough description, but it boils down to wanting to print values with pretty units. I would be willing to allow others to edit the notebook to fiddle around with fixing it.

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2013-10-22 20:16:50 +0100 commented answer Density plot aspect ratio

That worked perfectly, thanks ppurka! Also thanks kcrisman, you guys responded very quickly.

2013-10-22 03:17:59 +0100 commented answer Density plot aspect ratio

This is fantastic! I need to add a contour plot, some data points, and axes labels so I have more work to do. I tried to apply the patch according to the directions in the "Reviewing a patch" section of the developer walkthrough, but got an error that says 'abort: failed to synchronize metadata for "sage/plot/graphics.py"'. Is there another way to apply this patch? Can I edit the source myself without large risk of ruining my sage install? As an end-user this is both a little terrifying and awesome to me at the same time.)

2013-10-22 01:35:11 +0100 marked best answer Density plot aspect ratio

Thanks for reporting. It is a bug in Sage. Opened ticket 15314 to track this.

Update: Proposed fix is in ticket 15315.

Edit by kcrisman - here is what aspect_ratio=0.01 looks like with the proposed fix.

image description

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2013-10-21 15:23:45 +0100 asked a question Density plot aspect ratio

I am trying to make a very high aspect ratio density plot, but I can't seem to manually adjust the aspect ratio, and the automatically generated plot ends up being just a very pretty line. What am I doing wrong? The code I'm using is below. I don't know how to use Markdown to make it look pretty, sorry :(

print("Diffusion length data")
k = 1.381E-023
T = 300
q = 1.602E-019
var('ue')
De(ue) = ue*k*T/q
var('tau')
Le = (tau*10^-9*De)^(1/2)
D = density_plot(Le*10^4, (tau, 0, 3), (ue, 0, 500), cmap="jet")
D.show(aspect_ratio=0.05)
2013-09-27 02:32:26 +0100 answered a question Fermi-Dirac integral of half order

Sorry it took me so long to respond, life circumstances intervened.

First, sorry if the question wasn't clear enough. This is the first time that I have posted here so I am unfamiliar with the level of expertise in the community, which makes it difficult to write a specific, targeted question.

My original question had two parts:

  1. Can I use Sage to run the GSL algorithm to evaluate the Fermi-Dirac integral of half-order? I am only interested in the solution of this specific integral, not the solution of any other Fermi-Dirac integral. Other orders have analytical solutions, but the Fermi-Dirac integral of half order does not; it must be done numerically. Here is one reference asserting the same claim (click on it, press ctrl+f and type in numerical to get to the specific sentence): nanohub.org

  2. If I cannot use the GSL function, what other options are there?

The first has gone unanswered. The second has been soundly answered and I am grateful for your response! Barring an affirmative answer to the first question, I will use the numerical_integral command to evaluate this integral.

I am, however, troubled by your comments in general. I like SAGE because it is a free and open-source alternative to very expensive software packages like MM. Any work that I do in MM I lose as soon as I don't work somewhere that maintains a MM license, which is almost anywhere other than academia. Suggesting that I use MM seems to go against the stated purpose of SAGE and it's creator's original intent. I understand that in certain circumstances it is a more capable tool. That's fine, but SAGE includes at least 3 packages dedicated to numerical computation (octave, numpy, and scilab). I thought I would at least get a suggestion about how to use one of those tools as an alternative to the GSL algorithm before running to MM with my tail between my legs.

Further, your suggestion that MM "knows" how to perform this integral analytically and does so is an egregious error. The Fermi-Dirac integral of negative half order (used in your example) must also be done numerically (quick google search). Even the answer given by MM, a number and not an expression, suggests that it is not employing a symbolic solution, but is indeed switching to a numerical method. It's equally possible that MM is programmed to recognize Fermi-Dirac integrals and respond accordingly. It should be noted that I found no evidence in the MM documentation to suggest that either one of our answers is correct. This is the core problem of the MM black box, and another reason why SAGE is valuable. In this case, the Maxima engine in SAGE is outperforming MM by providing a more accurate and predictable (although useless) outcome. The only thing the MM result confirms is that the numerical_integral method in SAGE provides the same answer. This suggests that MM is correct because it can be compared against ... (more)

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2013-09-06 14:20:20 +0100 asked a question Fermi-Dirac integral of half order

I am trying to implement a 1D model for semiconductor pn-junctions. This involves evaluating the Fermi-Dirac integral of half order, which can only be done numerically. I saw that the GSL library has an algorithm to perform this integration, but I can't figure out how to call it in Sage, is this possible? If not, what are some alternatives to evaluate this integral? Thanks in advance.