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2014-09-24 21:01:20 +0100 answered a question Insufficient RAM for computing newforms

In Sage 6.1 on MacOS X in a Fedora 20 VM on VirtualBox. Model: iMac Processor: Intel Core i7 (QuadCore) RAM: 16 GB.

The VM needs a lot of CPU-Time and the use of RAM increases constantly.

Start: 1.9 GB RAM After: 30 Min. 2.3 GB RAM After: 60 Min. 2.6 GB RAM

I cancelled the calculation after 60 Minutes.

2014-09-19 16:04:56 +0100 answered a question Good computer for fast computation

I answer the question, about your $1500 three years later, but I think you have all ready bought your fast computer. In 2014 a fast computer should have a SSD Hard Disk >= 120 GB or more, 8-16 GB RAM DDR3-1600 or better an i5 or i7 for the consumer section makes not a great difference which CPU you have. The graphics card is not important if you only want to draw some of your plots the build in graphics card of the i5 or some models of i7 is enough, but an Nvidia or AMD Graphics card is also a good option.

About GPU's power, yes it is true in some cases the GPU can speed up computation extremely, but this works not in all cases. Today (year 2014), their are only a few programs that uses the GPU power for calculation, because it is difficult to write software for combined GPU <-> CPU power usage.

It is important to say, today you could use Sagemath Cloud for your computation. On Sage math cloud you could use a lot of power if you want Sage math cloud limits

As Kelvin Li says, if you really want to compute fast use Linux, because Sage works really fine with Linux. Linux Distributions that I know which has a nice Latex and Sage support are:

  • Manjaro Linux (Arch Linux for) - which has up-to-date Sage packages, also Latex (texlive-*) packages, a really high quality documentation and a dedicated community.

  • Fedora - which has up-to-date Sage packages but they are some minor versions behind the latest packages, good Latex support (texlive-*)

  • Ubuntu or Linux Mint with the additional PPA-Sagemath-Repository , both have a good Latex support and a large user base

2014-09-19 13:21:51 +0100 commented question How to graph this function in Sage plot?

Can you make the function more readable please, I think you mean this c*log(x) - x*d = -a * log(y) + b*y + y0

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2014-09-18 15:02:04 +0100 answered a question Custom color map for matrix plot?

@kcrisman is absolutly right:

here are some code examples based on that articel Custom Colormaps

With a lookup dict:

from pylab import *
cdict = {'red': ((0.0, 0.0, 0.0),
                 (0.5, 1.0, 0.7),
                 (1.0, 1.0, 1.0)),
         'green': ((0.0, 0.0, 0.0),
                   (0.5, 1.0, 0.0),
                   (1.0, 1.0, 1.0)),
         'blue': ((0.0, 0.0, 0.0),
                  (0.5, 1.0, 0.0),
                  (1.0, 0.5, 1.0))}
my_cmap = matplotlib.colors.LinearSegmentedColormap( 'my_colormap', cdict, 256 )
matrix_plot( matrix( [ [1,3,5,1], [2,4,5,6], [1,-3,5,7] ] ), cmap = my_cmap, colorbar = True )

From pool:

from pylab import *
N = 8
cpool = [ '#bd2309', '#bbb12d', '#1480fa', '#14fa2f', '#000000',
          '#faf214', '#2edfea', '#ea2ec4', '#ea2e40', '#cdcdcd',
          '#577a4d', '#2e46c0', '#f59422', '#219774', '#8086d9' ]
cmap3 = matplotlib.colors.ListedColormap(cpool[0:N], 'indexed')
matrix_plot( matrix( [ [1,3,5,1], [2,4,5,6], [1,-3,5,7] ] ), cmap = cmap3, colorbar = True )

As gradient:

from pylab import *
startcolor = '#FF0000'
midcolor = '#FFFFFF'
endcolor = '#0030CC'
own_cmap1 = matplotlib.colors.LinearSegmentedColormap.from_list( 'own2', [startcolor, midcolor, endcolor] )
matrix_plot( matrix( [ [1,3,5,1], [2,4,5,6], [1,-3,5,7] ] ), cmap = own_cmap1, colorbar = True )
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2014-09-18 14:49:34 +0100 asked a question How to make a custom divergent colormap?

How can I make a custom diverging colormap in Sage? What I want is the same than the reverse seismic diverging colormap (Diverging Colormaps) but the blue value should be less intense (e. g. conflower blue [Hex color code: #6495ED]).

In the sage source code I found the following link Diverging Colormaps, which explains the divergent colormaps and has a python class in the attachments. But still I have no clue to make such a diverging colormap.

I have also tried to make it with a LinearSegementedColormap:

from pylab import *
startcolor = '#FF0000'
midcolor = '#FFFFFF'
endcolor = '#0030CC'
own_cmap1 = matplotlib.colors.LinearSegmentedColormap.from_list( 'own2', [startcolor, midcolor, endcolor] )
matrix_plot( matrix( [ [1,3,5,1], [2,4,5,6], [1,-3,5,7] ] ), cmap = own_cmap1, colorbar = True )

but the result is absolutely not what I want, because it goes too fast from red into pink.

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2014-09-12 14:43:36 +0100 commented answer How can I plot matrices from Database into different sage cells?

The looping is exactly what I want, but is there no possibility to make a new cell directly in the sage notebook?

2014-09-12 14:41:26 +0100 commented answer How can I get the cell id of the current cell in a worksheet?

the problem was I could not convert kcrisman's answer to an answer.

2014-09-12 14:40:31 +0100 answered a question How can I get the cell id of the current cell in a worksheet?

sagenb.notebook.interact.SAGE_CELL_IDis exactly what I want. For more information see this answer: http://ask.sagemath.org/question/8954.... Big thanks to kcrisman.

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2014-09-08 19:18:30 +0100 asked a question How can I get the cell id of the current cell in a worksheet?

How can I get the cell id of the current cell I work with? I think of something like: self.get_current_id()

2014-09-08 19:12:30 +0100 commented answer Custom color map for matrix plot?

I try this thanks

2014-09-08 19:10:24 +0100 asked a question How can I plot matrices from Database into different sage cells?

How can I plot multiple matrices from a sqlite Database into different sage cells?

My first intention was iterate over the SQL result set with python in sage and plot every result into a different sage cell. But I do not know how I could plot them into different sage cells?

Why I would do that? Thats simple I have between two and over 20 Matrices and every matrix has the dimension of 91x365!

2014-09-08 17:27:10 +0100 asked a question Custom color map for matrix plot?

I need colormap which has for a fixed value x the color white and all values above x are colorized from white do blue and all values below x are colorized from white to red.

The first question is, is this possible? And my second question how can I do that?