20190112 11:00:58 0600  asked a question  How to configure jupyter for Sagespecific use? I am an absolute beginner in using jupyternotebooks. Since SageMath version 8.5 the user is asked to be prepared for using jupyter as the standard notebook in the future. So, in Linux I activate jupyter with ./ sage n jupyter and do some experiments. In this way, obviously, SageMath activates an internal jupyter package via an internal notebookinterface (and not via an external jupyter installation e.g. in anaconda). I tried also to edit python code within a jupyter cell. I got some unexpected errors, so editing code in jupyter cells seems to be problematic. Also, I want to figure out, why editing python code within a jupyter cell changes the color marks of some 'if' statements to red? Sometimes, after reopening a closed jupyter session appears as plain text only, i.e., without cells. My simple question is therefore: Is there any documentation available for the sagespecific use of jupyter (e.g., meaning of color code for the elements of the python language, extra necessary import of additional sage objects for jupyter, configuration of jupyter, etc)?. 
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20180604 14:57:09 0600  answered a question  convert charpoly()generated characteristic polynom to symbolic expression I just found that characteristic polynomals of matrices can also be converted to SR by substituting one of their symbols with subs. 
20180604 13:51:16 0600  commented answer  convert charpoly()generated characteristic polynom to symbolic expression Thank you very much for the hint. I need the conversion to SR in order to simplify the expression with canonicalize_radical() or with factor(). This seems not be possible if I apply them on the unconverted expression (unimplemented error or attribute error). I just found that characteristic polynomals of matrices can also be converted to SR by substituting one of their symbols with subs. 
20180604 13:21:46 0600  answered a question  convert charpoly()generated characteristic polynom to symbolic expression Thank you very much for the quick response, However, I want to calculate the characteristic polynom of a matrix containing symbols, e.g.:

20180603 12:33:33 0600  asked a question  convert charpoly()generated characteristic polynom to symbolic expression A characteristic polynom that is generated by the procedure charpoly() has the type:
How can I convert it to one of type 'symbolic expression' without doing 'copy and paste'? 
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20180322 15:37:27 0600  commented answer  Mathematica misinterprets some underscored symbolic variables I agree, The best method to circumvent this problem is substituting the "_" symbol by unique identifiers in sage and subsequently replacing them in Mathematica by its appropriate underscoring. key combination. This workaround should be applied to all kinds of underscored symbols (not only for underscored numbers). 
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20180321 02:25:24 0600  asked a question  Mathematica misinterprets some underscored symbolic variables Following examples show that the interface between sage and Mathematica misinterprets symbolic variables if they are underscored with numbers: I use sage8.1 and Mathematica 11.2.0 at Linux OpenSUSE Leap v42.3. In this forum I haven't found any other comment regarding this funny behaviour. 
20170509 09:48:50 0600  asked a question  Interactive solving differential equations with MAXIMA's desolve I am using Maxima's "desolve" to handle a system of linear differential equations.
During processing, Maxima arrives at an intermediate expression (in my case this is a complicated argument of a sqareroot)
that may be positive, negative or zero. Maxima asks me interactively if this expression is negative, positive or zero.
If I use "desolve" directly within the Maxima's notebook, I can give my answer interactively
(e.g., "pos") to Maxima. Consequently, Maxima can continue processing immediately.
Thus, in Maxima's notebook there is no need to use an 'assume' statement that includes
the whole complicate expression in question.
On the contrary, processing this system via Maxima's 'desolve ' at a sage's notebook is very inconvenient,
since, according to sage's documentation, one can answer such questions only via assumes given prior to 'desolve'.
Moreover, in the treated case Maxima ignores such 'assume'statements.
Thus, solving my equation system at Maxima via sage turns out to be impossible. Here is a simlpe executable example for interactive working with Maxima. (Members of Maxima's discussion forum gave this example to me for demonstration) I tried to answer this question interactively at a sage notebook. Unfortunately, This leads to a deadlock in the sageplatform (version 7.4). 
20160905 17:17:12 0600  commented answer  ATAN2 AssertionError while plotting complex squareroot function I have checked this in the cloud and also in my private 7.3 version. I made additional checks: An integer delta=1 is ok, but unfortunately a real delta=1.0 results in the same error. Also delta=real(1) is ok, but not delta=real(1.0). Thus, the problem persists, which obviously is caused by a wrong type conversation. 
20160905 14:59:22 0600  asked a question  ATAN2 AssertionError while plotting complex squareroot function

20160424 17:09:59 0600  asked a question  store python code from a notebook cell to a file During a notebook session I enter a series of SAGEstatements (python code) in a notebook cell. How can I let SAGE store/save this code automatically (not via copy&paste) in a file? The purpose is to reload the stored code in a cell of another session for later processing . I tried to perform this via the "savesession" command. However, this results in a data volume of several MB, which is much larger than the total length of the code of the session. This I want to avoid. 
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20151109 07:48:26 0600  asked a question  Substituting derivatives in Taylor expansions Within Taylor expansions, as well as in results of 'Derivative' operations, derivatives are marked by symbol "D[ ]" . I want to substitute them by other symbolic expressions/functions in order to get the usual presentation of derivative symbols via Latex. The following testprogram demonstrates that derivatives triggered by the "derivative"operation can indeed be substituted by userdefined symbols, but not derivatives in Taylor expansions. I run this program within In a SAGE6.8 notebooksession. The output is: After a "derivative"operation, substituting dt1 by dTedx works: After Taylor expansion, substituting dt2 by dTedx does not work: What is the reason for this difference? Maybe, I merely must access the derivative expression within a Taylor expansion in a different way. Thus: which is the correct way to do this? 
20141129 16:34:34 0600  commented answer  How to define more complicated differential expressions in Sage? I want to add a remark concerning the real problem with D0(y). You can substitute the default output of an derivativeoperation, e.g. D[0] (fxx)(z) by any symbolic function you want by using the 'derivative_func' option of 'function'. Following Example using symbolic function definition
var('z') dfxdz=function('dfxdz',latex_name='\frac{\operatorname{d}{x}}{\operatorname{d}{z}}') def dfx(self,args,*kwds):return dfxdz(z) fxx=function('fxx',latex_name='x') fx=function('fx',derivative_func=dfx,latex_name='x') For the input fx(z).derivative(z) #with derivative_func you get the output : dfxdz(z) For the input fxx(z).derivative(z) #without derivative_func you get the output: D[0] (fxx)(z) 
20141125 12:08:57 0600  answered a question  How to define more complicated differential expressions in Sage? Perhaps the answer I have given for the question "latex typesetting for derivatives" at 31.Oct. can help you. One can utilize the option "derivative_func" of Function to let perform a list containing the requested results of the partial differentiations during processing a product rule or a chain of differentiations. 
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20141031 13:28:36 0600  answered a question  latex typesetting for derivatives like g' Obviously it is possible to assign any latex text to derivatives by using the ' derivative_func' option of the 'function' procedure. Below I have addad an example that I have executed in the SAGE V63 environment. var('z') def dfx(self,args,*kwds):return dfxdz(z) def dfy(self,args,*kwds):return dfydz(z) fx=function('fx',derivative_func=dfx,latex_name='x') fy=function('fy',derivative_func=dfy,latex_name='y') dfxdz=function('dfxdz',latex_name='\frac{\operatorname{d}{x}}{\operatorname{d}{z}}') dfydz=function('dfydz',latex_name='\frac{\operatorname{d}{y}}{\operatorname{d}{z}}') dgdx=function('dgdx',latex_name='\frac{\partial{g}}{\partial{x}}') dgdy=function('dgdy',latex_name='\frac{\partial{g}}{\partial{y}}') pdev=[dgdx(fx(z)),dgdy(fy(z))] xf=fx(z) yf=fy(z) def pderivg(self, args, *kwds): print "args:",args; print "kwds:",kwds,pdev[kwds['diff_param']]; return pdev[int(kwds['diff_param'])] gf = function('gf', latex_name='g',nargs=2, derivative_func=pderivg) g=gf(xf,yf) deriv=g.derivative(z) show(deriv) 