All Questions

7 views

Partial differential equation with infinity limit

How do I get Mathematica to solve the following partial differential equation $$\frac{\partial u(y,t)}{\partial t} = \nu \frac{\partial^2 u(y,t)}{\partial y^2}+\frac{\partial U_0(t)}{\partial t}$$ ...
11 views

How to implement QLearning?

I know that v10 has support for both Machine Learning and Finite Markov Processes, the Q-learning algorithm uses both. Specifically, Q-learning finds an optimal action-selection policy for any given ...
8 views

Call user defined function from many notebooks

I wanted to ask a simple question. I am new to Mathematica, and I dont find a way to call user defined functions just as I call Mathematica functions. I want to use my own defined functions, but ...
24 views

How to couple NIntegrate with FindMinValue

I have a problem with a correct transfer of values of parameters when NIntegrate (and some subsequent functions) are coupled with minimizing procedures in ...
37 views

Alternative to the DiscretizeRegion?

I have a polygon: pgn = Polygon[{{0, 0}, {0, 0.018}, {0.155, 0.018}, {0.155 + 0.015, 0.008}, {0.222, 0.008}, {0.222, 0}, {0, 0}}]; here: ...
33 views

About functions of a matrix [on hold]

I have a matrix problem. My question is: $f(x) = 3x + 1$, find $f(A)$, where $A = \left(\begin{array}{} 1 & 3\\ 2 & 0\\ \end{array}\right)$.
38 views

How to solve this equation? Which command should be applied? [on hold]

I am trying to find T1 from attached equation, but it can not solved by "solve" in mathematica. how could i solve this equation?
36 views

NMaximize is not doing what I intend [on hold]

Why does NMaximizegive the wrong answer in following script: ...
11 views

Interrupt evaluation of script with exit code 1

I am running a Mathematica script I wrote as a batch job from a terminal, running it many times inside a loop inside a Bash script. Sometimes I want to abort the job. I can of course do ...
20 views

How to import interpolating function of large size?

I was generating a set of eigenfunctions from a differential equation using NDEigensystem.Due to the cost of time is too high,I thought it'd be better if I export ...
21 views

Reaction-diffusion PDE with NDSolve: either very slow or very inaccurate

I am struggling to have Mathematica 10.3 solve a system of PDE's (with periodic boundary conditions and random initial conditions), but either it produces a set of very noisy InterpolatingFunction ...
44 views

Using ListInterpolation to get a vector-valued function

I wanted to construct a ColorFunction from an image, so I tried ...
52 views

Solve and plot differential equation

I want to solve this differential equation $\qquad y'(x)=\frac{x-y(x)}{1-y(x)-x}$ and plot it's solution. But DSolve doesn's work. ...
52 views

How to equate coefficient of two polynomials?

Given two polynomials, How can I equate coefficients of them in Mathematica? For instance a + b x + (c+d) x^2 + (e+f)x^3 == 0
130 views

How can one manually change the rule ordering

I have a function which has some general behaviour, but that should act on some specific kinds of objects in some other way. I know that Mathematica is supposed to automatically order the rules so ...
139 views

Plotting a function with three real arguments using transparency

I would like to plot a real function with three real arguments by assigning a transparency and color to the function values. The smallest value in the plotting range should be fully transparent, the ...
23 views

Display line number/stack trace of error in script (i.e. batch mode / command line interface)

I am trying to set up a Mathematica script so that it runs from the command line in the manner that a sane person would expect. I have the following at the start of the file: ...
30 views

I've read similar-but-not-quite-the-same questions : I have to read a python-generated data file which contains complex numbers. So, the numbers appear as (real+imag j). And of course Mathematica ...
65 views

How to improve speed of the following code

The following code do what I needed, but it takes too long ...
39 views

How to properly set ColorFunction and Specularity in ReliefPlot

I have two questions about ReliefPlot: How can I set the Specularity without changing ...
38 views

How to handle a special Neumann-like boundary condition in NDSolve?

How to solve the following nonlinear ODE with two algebraic equations and one boundary condition? ...
177 views

Is there a function in Mathematica which removes brackets wrapping an expression?

Is there a function in Mathematica which removes brackets from an expression? RemoveBrackets[ {3} ] 3 Note: inspired by @garej's answer to this question ...
43 views

How to plot equally discrete points?

I'm trying to create a table of equally discrete points and plot them with: a = 5 ListPlot[Table[{a/9*(i - 1), a/9*(j - 1)}, {i, n}, {j, n}]] But I cannot plot ...
14 views

i need bifurcation diagram for system of differential equarions [on hold]

function xdot = fzr(t, x) r=5;k=830;b=0.011;e=0.1;c=0.4;d1=0.5;d=0.5;g=0.0092;h=0.09;v=1.58;m=0;v1=0; xdot = zeros(3,1); xdot(1)= rx(1)(1-(x(1)+x(2))/k)-c*x(1)x(2)-bx(1)*x(3)+m+v1*x(2); xdot(2)= ...
33 views

Error propagation code [on hold]

I have a code for error propagation :- ...
63 views

How to do Independent Component Analysis?

The new experimental function in 10.3.1 DimensionReduce[], has the following three options for Method: ...
26 views

Can't clear variables with subscripts [duplicate]

ClearAll["Global*"] doesn't clear subscripted variables. It won't clear these variables for example. ...
32 views

Is this logarithm equation right? [on hold]

i'm new in this forum want to ask a beginner question about logarithm Is log [t^2 *(l/c)] is log (t^2) * log (l/c)
46 views

Running an entire notebook with different values of an input

I have about a 20 cell notebook which begins at n=3. By replacing 3 by other natural numbers, I can compute what I want using these values, but I do not understand ...
55 views

Programmatic immersion of 2D surfaces in 3D [on hold]

Disclaimer: This may be an open problem, or one that is too large to be amenable to a solution on this site; I'm not sure. Question: I'm looking for a method to programmatically immerse certain ...
59 views

Expression of an integral

I am doing the following integral in Mathematica with $a>0$, $\int \int e^{ -\left ( x_{1}+x_{2}-2b \right )^2/\left ( 4a \right )}dx_{1}dx_{2}$. My code is ...
58 views

Is the “Custom Extension of C” that Mathematica is partially written in available for use or review? [on hold]

Reading this answer to the question of what Mathematica was written in I found this intriguing snippet: The C code in Mathematica is actually written in a custom extension of C which supports ...
46 views

Multiplying matrices which should multiply produces an error message [on hold]

I have developed a PCA (principal component analysis) method for any image. However, I get an error -- objects of unequal length -- when I try to compute "final data", and I really don't understand ...
95 views

how to map a function on a variable list

The following is just an example that captures what I want to do (more on it at the bottom). I'm trying to do something that can be paraphrased as follows: I have a global list, say ...
25 views

Integration over n variables and its expression [on hold]

I am having a problem with the following n variable integration and we know $b>0$. $\int ...\int exp \left [-\left ( \sum_{i=1}^{n} x_{i}-an \right )^2 /(2bn) \right ]dx_{1}...dx_{n}$. My goal ...
60 views

Ex-post monochome plots

I need to "monochromize" a large amount of plots (mostly coming from ListPlot) and export them to PDF. The problem is that I no longer have the data used to ...
44 views

Importing LaTex

I have a LaTex file, and import it this way: tex=Import["texfile.tex"]; Now according to Help, this returns a notebook expression: ...
54 views

LinearModelFit: How to compute R-squared? [on hold]

Is there a simple way to computed the R-Squared(adjusted and not adjusted), from the LinearModelFit? It has so many options, but none for the R-Squared, that I suspect there's a simple way to compute ...
72 views

How to make a flowchart? [on hold]

I'd like to make a flow chart in similar to this: I think it's more of a layout and stylistic question for a graph - how to style a graph with labeled edges and vertices so that it looks like a ...
1k views

How was Mathematica built?

I've been wondering this for a while now: How Mathematica was built? Is it written in Haskell? C++? I'd love to get a taste of the wizardry behind this incredible software.
27 views

System of ODE's in NDSolve [on hold]

To begin with, I understand that this is quite a common question, with a lot of documentation from Wolfram and answered questions on this stackexchange. I have been looking over them, I really have, ...
53 views

Is this problem parametrically solvable or it can just be solved for specific $\sigma$ and $\theta$?

In order to solve This problem: What is the maximum value of coefficient fv with the constraint that the matrix is positive semi-definite?, I have used the following code (Determinant is computed by ...
21 views

Vertical alignment of a cell used as value for CellFrameLabel

Consider that label, used as value for CellFrameLabel: ...
41 views

I have: ...
61 views

How to get the training error and the validation error using Classify function with SVM

I am using Classify[] function with Support vector machine model. I need to analyze the quality of results by analyzing the training error and the validation error ...
49 views

To find a limit cycle with period 1 in NDSolve

I am trying to find a limit cycle with period 1 of an ode system. The idea is to compare the values of the system during two periods, for example, ...
44 views

Image processing for tic tac toe [duplicate]

Last weekend I was at a hackathon at Georgetown University where my team and I wrote a python program that allowed our home made delta robot to autonomously play tic tac toe with a human user. The ...
72 views

Plot markers for monthly data

I have the following data ...