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20201215 23:42:31 +0200  commented answer  Square, cube, octahedron, equations Thank you for your reply. She made me understand that I have math gaps. I'm going to check out math sites to try and figure out what Linfinity norm is. I have cut out! 
20201215 11:00:00 +0200  asked a question  Square, cube, octahedron, equations We know that $x + y  1 = 0$ is the equation of a square having its vertices on the axes. I asked to represent the equation $x + y + z  1  0$, believing to obtain a cube in space. But I obtain an octahedron. Why? And how do you get a cube? 
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20200826 10:18:15 +0200  answered a question  output.txt not updated This problem has already made me bitch a few times until I found a solution: I copy the script to a new cell, make the modifications and there I get a new "full_output.txt file" which takes into account my modifications. One response says: "But reloading should get you what you want." I have found that this is not true! the old "full_output.txt file" is still present. (sorry for my bad english, i use google translator) 
20190124 16:28:04 +0200  commented question  Problem with boring message Excuse me for the delay in answering you. I did a restoration of my previous work to the problem caused by the use of LaTeX, which I do not need, and everything is back to normal. Sorry for your lost time. 
20190119 23:12:50 +0200  commented question  Problem with boring message Good evening, I do not use Latex.After being seen on the site ctan.org I decided that I did not need Latex. I also tried bits of codes like to see what that gave. As said in my request I always get the following message. Error: PDFLaTeX does not seem to be installed. Download it from ctan.org and try again. None What is serious now is that if I activate cells that already contain code that worked I still get this message and nothing else. 
20190119 17:45:55 +0200  asked a question  Problem with boring message In one of my worksheets I wanted to test Latex. I was directed to ctan.org After reading a bit about it, I decided that I did not need it. But since this test, whenever one of my exercises launches I get the following message and nothing else. How to get rid of this? Thanks in advance for your time. Error: PDFLaTeX does not seem to be installed. Download it from ctan.org and try again. None 
20181206 09:43:04 +0200  commented answer  Speed a function with hex grid and primes numbers I did two more tests, here is the result: I think the matrix has become too big. We must find another method of resolution, either mathematical or computer. I'll think about it. Anyway thank Mr. Lelièvre you for your help that allowed me to learn new concepts about prime numbers. 
20181205 10:52:19 +0200  commented answer  Speed a function with hex grid and primes numbers I'm going to run the program for more value from "lim" quite to running my computer all night. I will provide the results later. 
20181205 10:47:09 +0200  commented answer  Speed a function with hex grid and primes numbers I tested your second idea in more depth. As soon as we increase the value of "lim" it is your second idea that is the most powerful. The curve that adjusts the pairs of points (DP3, time) seems parabolic or exponential. So it's not pleasant since you have to reach a DP3 = 2016. Rather than the brute force of the computer, there must be a simpler mathematical process that goes beyond me. It is simply frustrating to feel incapable of not knowing the right simplification techniques. Thank you 
20181204 00:10:08 +0200  commented answer  Speed a function with hex grid and primes numbers Thanks for your answer but your idea is slower. I have made a little try.

20181130 17:31:22 +0200  asked a question  Speed a function with hex grid and primes numbers Hello, I am trying to solve the question 175 of the Turing Challenge. We create a network of hexagonal tiles containing the following integers 1, 2, 3, 4, ... I represent this network in a square matrix by placing the number 1 in the center of the matrix. We must calculate the difference between each tile numbered n and each of its six neighbors, we will call DP (n) the number of these differences # which are a prime number. My problem is this: I have to calculate a lot of times the function below. We save in DP3 the n which are surrounded by exactly 3 prime numbers. Here is all my script. My idea is this: every time I have completed a turn I can calculate the DP3 of the previous turn. The program stops when len (DP3) = 2016. As the spirals become bigger and bigger you have to make more and more calls to the DP3 () search function. My question is: is it possible to speed up this function? PS: I'm sorry for my bad english. I also note that I am a beginner in programming. 
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20181027 10:21:52 +0200  commented answer  Strange factoring in e = (x+1)^3*(x+2)^3*(x+3)^3*(x+4)^3 Thank you very much for your answer. I think I understand it and do exercises on this subject. Actually print q in my code would have put me on the path. But I also believe that I still have a lot of work to do in the field of SAGE. I have downloaded the free book "Calcul Mathématique avec Sage Alexandre Casamayou Nathann Cohen ....) and I will study particularly the chapters 11 and 7 that will be very useful, I think, to understand your explanation. Not a problem because I'm retired  I'm 78 years old  and I enjoy solving the little problems that I encounter on the internet (like Euler Project, Turing Challenge, ...) Again thank you for your answer. Excuse me for my Google translation. 
20181024 14:48:08 +0200  received badge  ● Editor (source) 
20181024 14:44:40 +0200  asked a question  Strange factoring in e = (x+1)^3*(x+2)^3*(x+3)^3*(x+4)^3 After reading a question about QUORA I had fun with Sage to test expressions factoring. If I ask to factorize e = (x+1)^3(x+2)^3(x+3)^3 everything is ok. But when I ask to factorize e = (x+1)^3(x+2)^3(x+3)^3*(x+4)^3 the result surprises me and I do not understand why! Here is my script and the results. Now the results As you can see when I the use of ComplexField(16) give me 12 roots (10 complex ans 2 false reals for me).This is totally different of ComplexField(32) which give the right answer. Why? Thank you in advance for enlightening my lantern. 
20181024 12:01:52 +0200  commented question  drawing the function y = log x Thank you very much for the answers. They show me that I still have to study a lot Sage. 
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20181019 13:51:12 +0200  asked a question  drawing the function y = log x When drawing the function y = log x, I know that x must be positive but I have varied x from 5 to 5 by habit. I had no error message and a graph having a part in the box x<0. I would have liked to attach the graphic but that is denied me. 
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20170731 00:24:54 +0200  commented answer  how find quickly the order of a long prime ? thank you for your explanations. I see that I still have a lot to learn. It's frustrating to be stuck in solving a problem because I do not know all the tricks that make a program much more effective. Where can I find answers? Which book or site or ...? 
20170731 00:15:17 +0200  commented answer  how accelerate this simple program thank you for your explanations. I see that I still have a lot to learn. It's frustrating to be stuck in solving a problem because I do not know all the tricks that make a program much more effective. Where can I find answers? Which book or site or ...? 
20170729 00:14:16 +0200  commented answer  how accelerate this simple program Good evening. A very big thank you for your long explanation that I find extraordinary. I would never have thought of doing that. I read and reread your text several times and I think I understood the principle. The result is found in just over a second! It's awesome 
20170728 23:41:36 +0200  commented answer  how accelerate this simple program Indeed your code works more than 100 times faster. I do not understand why RR (math.sqrt (n)) is 100 times faster than N (sqrt (n)). Where can I find an explanation (as simple as possible)? I tried your cython code and I get the following error. compilation terminated. error: command 'gcc' failed with exit status 1 Is not Sagemat already written in cython? 
20170728 23:24:49 +0200  commented answer  how find quickly the order of a long prime ? Thank you for your feedback. They remind me of my early years (I am 77 years old) when I tried to understand and assimilate the theorems of Fermat and Wilson. At the time I found it very difficult. Now, with a computer, as it is possible to experiment I try to solve problems (found on Euler and Turing project sites). If you could advise me a book or documents dealing with the simplest way possible by examples I will be grateful. 
20170728 00:37:44 +0200  asked a question  how accelerate this simple program Hello everybody. Here is my question We seek integers of which the decimal part of their square root begin by 2017. Sample: sqrt(10858) = 104.201727.... Here is my program: the problem is it takes too much time. For the bound 10^5 it takes about 55 sec on my iMac, for 10^6 it takes 620 sec, for 10^7 it takes almost 6000 sec ... The question is to obtain the result for the bound 10^10 ! 
20170727 18:49:25 +0200  marked best answer  how find quickly the order of a long prime ? Is it a quicker way for finding the order of a long prime without the inner loop for? I know that a prime number p is long iif is order is order is p1 