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2017-06-08 15:41:39 -0600 commented question Symbolic algebra: Sage, Maxima, Ginac, Sympy?
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2017-03-06 12:27:37 -0600 asked a question Symmetry-finding

On pp. 152-3 of Hydon's Symmetry Methods for Differential Equations (2000 ed.), he lists some computer packages for symmetry-finding. This related Mathematica StackExchange question mentions the SYM Mathematica package and Maple's DEtools/symgen. Does SAGE have anything similar for doing symmetry-finding?

2017-03-04 08:48:49 -0600 commented answer Error installing package mpir-2.4.0.p6

I'm getting this issue with the Sage 7.5.1 release.

2017-03-04 08:48:19 -0600 commented answer Error installing package mpir-2.4.0.p6

Unfortunately that didn't work for me.

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2015-03-26 22:10:00 -0600 marked best answer How do I deal with large, hex numbers in Sage?

How do I deal with large, hex numbers in Sage (say ones with 256 or 512 bytes)? How would I import them from a CSV file?

(cf. this related answer)

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2015-03-18 01:44:39 -0600 commented answer implementing Lie-admissible algebras

What about the comments here? Are those options good, too?

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2015-03-18 01:07:19 -0600 commented answer implementing Lie-admissible algebras

This is what I expected for an answer. I'm not looking for how to do every detail of such an implementation, but where to start. Thus, you've answered my question. thank you

2015-03-17 13:38:39 -0600 asked a question implementing Lie-admissible algebras

How would I implement Lie-admissible algebras in Sage?

A Lie-admissible algebra is "A (non-associative) algebra (cf. Non-associative rings and algebras) whose commutator algebra becomes a Lie algebra." Read more.

Lie-admissible algebras are classified as 17D25 on MSC2010.

2015-03-17 12:00:59 -0600 commented answer performing a higher resolution FFT

Oh, yes, using a windowing function is a good idea. thanks

2015-03-17 12:00:13 -0600 commented answer single PDF of Sage Reference manual?

Just ignore it. It's a self-signed cert because I'm too cheap to buy a CA-issued one…

2015-03-17 01:13:22 -0600 asked a question performing a higher resolution FFT

How do I interpolate (up-sample) a discrete function so that I can perform a more refined FFT spectral analysis on it?

(Note: By default, NumPy's FFT command produces a list of the same dimension as the input list.)

thanks

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2015-03-13 20:10:57 -0600 answered a question List Density Plot?

They key is to use hist2d:

import matplotlib as mpl
import matplotlib.pyplot as plt

px,py = x,y

nx = ny = 100 #number of bins in x,y directions
x_bins = np.linspace(px.min(), px.max(), nx+1)
y_bins = np.linspace(py.min(), py.max(), ny+1)

plt.xlabel('Nonce');
plt.ylabel('Hash ($\log_{10}$)');
plt.title(r'2-D Histogram of First '+str(len(x))+' Valid Nonces and Hashes');

plt.hist2d(px, py, [x_bins,y_bins], norm=mpl.colors.LogNorm());

plt.savefig('Density Plot (log colorscale).png')
plt.close();

This produces a nice plot: hist2d plot

2015-03-13 20:05:00 -0600 commented answer List Density Plot?

Actually, hist2d is what I was looking for.

2015-03-13 14:33:09 -0600 commented answer List Density Plot?

Actually, I want to do this for discrete values, not functions, so a need to use histogram2d, as here.

2015-03-11 11:46:02 -0600 commented question Displaying a numpy plot

I'm using Sage with KDE Cantor on Linux.

2015-03-09 20:31:13 -0600 commented answer How do I deal with large, hex numbers in Sage?

Here's what I did, and it works very well:

import csv
    mylist=[]
    with open('~/Downloads/datasmall.txt', 'rb') as csvfile:
         data = csv.reader(csvfile)
         for row in data:
             mylist.append([int(row[1]),float.fromhex(row[2])])
2015-03-09 20:07:12 -0600 edited question List Density Plot?

How can I make a 2-D density plot of a list of values in Sage?

I'd like to make something like this: Density map (image source)

2015-03-09 19:42:05 -0600 commented answer List Density Plot?

I'm dealing with over 300,000 points, and

p = Graphics()

for n in range(len(mylist)):
    
    p += point((mylist[n][0], mylist[n][1]),color=hue(n/len(mylist)))

is somewhat slow…

Any tips to speed this up?

thanks

2015-03-09 19:19:33 -0600 commented answer List Density Plot?

I just discovered the hue() function! That's exactly what I need! (I suppose I don't want to do a density plot as much a 3-D plot on a 2-D surface, where the third dimension is the color of the point.)

2015-03-09 19:17:29 -0600 commented answer List Density Plot?

I would like to color-code each point based upon a z-value.

2015-03-09 18:45:42 -0600 edited question Displaying a numpy plot
import matplotlib
import numpy as np

import matplotlib.pyplot as plt


 
plt.figure(figsize=(6, 3))

plt.plot(x, y)
plt.show()

Why doesn't plt.show() display my plot? plt.savefig('myplot.png') works, however.

thanks