Questions tagged [system-variables]

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Complete list of values for \$SystemID, \$OperatingSystem

The documentation lists some "typical values", but it leaves out some; e.g. "Windows-x86-64". Also, if the main difference between the two variables is that ...
389 views

Creating a variable from Reduce[] output in Mathematica

Say I have the following input: Reduce[{t*c==50, t==5}] the output: t == 5. && c == 10. Is there a way to create a ...
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How to obtain numerical solutions of a system of two equations with two unknowns?

I have two equations with two unknowns $-10<x<0$ and $0<y<15$ $$3 y \cosh (4 x) \cos (y)+(2 x+5) \cosh (x) \sin (y)=0,\\3 x \cosh (x) \cos (y)-(2 x+5) \sinh (x) \cos (y)=0$$ I would like ...
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Square root problem

Consider the following code NDSolveValue[{ x'[t] == x[t]^a, x[0] == 0 }, x, {t, 0, 10}] which solves the equation $x'(t)=x(t)^a$, for some exponent $a$, with ...
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Programmatically defining variables

I seems as though what I am interested in is unconventional, but I am interested in defining a number of different variables programmatically. For example I can write a matrix of variables by doing: <...
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Solving a multivariate polynomial system takes too long

I have tried to solve this system ...
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Is there a way to automatically store the output of a command to a variable directly?

Generally I do a computation then I have to manually take that number and make it equal to another variable which I define which I can then use to do subsequent computations. Something like this: <...
131 views

How to build a tri-diagonal matrix [closed]

I have an algorithm that works for a Tri-Diagonal matrix in Mathematica, but I need a good way to build my starter matrix A. It's a 20 variable system (and will be a 200 variable system once I get it)...
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Catching MachineUnderflow in Version 11.3

Ilian's answer to question 72229, involves SetSystemOptions["CatchMachineUnderflow" -> False] Evidently, this worked in earlier versions of Mathematica, but ...
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What is the purpose of the two variables Globalargs and Globaldims [duplicate]

When opening the mma, I find that two variables Globalargs and Globaldims have been defined. One can check them by running <...
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I've quite forgotten: what file does one modify in order to add directories to $Path globally? Specifically, I want to include ... 0answers 110 views Minimize and Table of variables I use a list of variables to Minimize a particular quantity { Q, val1, Table[Pi, {i, 1, m, 1}} where i is the subscript of P. However in this way I have ... 1answer 236 views Solving equation with multi variable matrix input Background, here are the equations that I am trying to solve: Where R, E1, E2, V1, V2, P are all user inputs. X/A goes from -2 to 2 and Z/A goes from 0 to -2. Below is the code that I have so far. ... 1answer 63 views Choice of variables name affects the behavior of expression evaluation I tried to expand this polynomials. With x, it is increasing with the right order, however with b it is in a random order. The only difference is that I change b to x and it works. ... 1answer 285 views How to permanently modify the$Path in Mathematica [duplicate]

I was trying to add permanently a path inside $Path. "/Users/gkdgoutam/Softwares/HEP_Softwares/MT-1.0" Following$Path manual I did the following ...
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Equivalent of __FILE__?

Many languages define a special identifier whose value is the path to the source file currently being processed. (For example, in C, this is done through the ...
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Solving a system of equations for a fraction

I want to solve a system of equations not for one specific variable but for a fraction of two variables. How can I do that? I want to solve: ...
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Interpretation of the result of ?@

This might be a very trivial question but as a beginner, I don't know the answer. I was exploring ? and after running a cell containing ...
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Newbie Issues with Solving & Plotting a System of equations

I'm having some problems with my mathematica code, I think I'm overlooking something simple. I get valid solutions for u0 thru u4, but it doesnt generate any plot at all. Also, I'd really like to plot ...
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I want to packed my program use RSA algorithm. Of course, $MachineID can be used but I want to make it safer. Can Mathematica obtain the computer's hard drive ... 0answers 221 views Shared variables between notebooks using the same kernel not working in mathematica 10.1? I am trying to access the variables over two Mathematica documents, this works fine when I use Mathematica 9 but when I attempt to do the same on 10.1 it doesn't work. I have set both notebooks to ... 1answer 238 views Is it safe to change the value of$TimeZone?

I'd like to configure some of my notebooks to assume all calculations using dates, times and locations (notably AstronomicalData , but others too) take place at the ...
724 views

How to set the timeout value for *Data functions

I haven't measured this precisely but it seems the default timeout value for retrieving EntityValues with *Data functions is in ...
638 views

To avoid execution problems in a program I need to know if Mathematica has been "Run as administrator". What would be the cleanest way to programmatically getting this information?
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Where can I find detailed information about the SystemOptions?

I'm looking to optimize my Mathematica script, and I'm willing to go spelunking with low-level system options. The problem is that I've been looking in the Mathematica documentation, but there doesn'...
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Mathematica not seeing my environment/system variables

I'm trying to access my environment variables in Mathematica, but I get a Failed result every time. For example: $echo$USER jlconlin but in Mathematica I do: ...
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Module function corrupts string? [closed]

I have the module who should replace some elements of a matrix with checkboxes ...
strictly positive solution to $Ax=b$
How to find in mathematica one real strictly positive solution, if any, of $Ax=b$. A is rectangular matrix. Thanks