# All Questions

1answer
465 views

### Problem with FindRoot applied to functions

I am having difficulty with the error "is not a list of numbers with dimensions..." when using FindRoot (and other numerical routines in Mathematica) to solve equations numerically when the argument ...
0answers
58 views

### Enormous and unclear output when using Solve

After running for about 30 minutes the program yields the below-given unclear output (of course I didn't copy the whole output, only a small part of it). So it explicitely gives 3 possible solutions ...
0answers
131 views

### The inverse Fourier transform of a rather complex function

I am using Mathematica 7.0 and trying to find the Fourier transform of a rather complex function g. The function g is defined by ...
1answer
77 views

### Using the string Match with options! [duplicate]

Here is what I want to do: I have a list of strings for example s={"red carpet","red box","black carpet","black box"} I want to use something like ...
3answers
893 views

### Mathematica style guide?

I encountered this site today https://code.google.com/p/google-styleguide/ regarding the programming style in some languages. What would be best programming practices in Mathematica, for small and ...
0answers
97 views

### Selecting values over lists for discrete inputs in NDSolve [duplicate]

I'm currently trying to simulate a step response in a simple tank system with NDSolve. I would like it to start at say time 2 (the precise time is not important). ...
1answer
116 views

### Wrong generalized eigenvalues of large numeric matrices

I've been working on a toy model of a variational method of a Hamiltonian H with an overlap matrix S. The point is that when H and S are small enough, Mathematica gives the correct eigenvalues (≈ ...
1answer
120 views

### TransformedRegion, RegionPlot broken in 10.0.2.0?

After having had trouble applying TranslationTransform to a simple region like so ...
2answers
482 views

### Graphics3D: Objects with holes

In a recent project, I found out that there is a big limitation when using Graphics3D to construct objects - it lacks the ability to construct objects with holes in ...
1answer
161 views

### No legends in parametric plot

plotting some descibing functions, I wondered why I don't get any legends in my plot. The describing functions (and options): ...
1answer
221 views

### Checkerboard background on plot (potentially using prolog)?

Currently I have a plot of a complicated function with gridlines turned on. Is there a way to shade a checkerboard pattern of alternating colors between adjacent grid cells? So far, I have tried ...
0answers
26 views

### why i cannot get appropriate number with my custom precision? [duplicate]

why i cannot get appropriate number with my custom precision? In[25]:= N[(1 + Exp[-30])/(1 + Exp[-29.9]), 1000] Out[25]= 1. I expect to see a few digits after ...
1answer
124 views

### How can I change variable passed to a function? [duplicate]

Sometimes I'd like to make a function, which would take an argument "by reference" instead of usual "by value". This is semantically similar to what e.g. AppendTo ...
1answer
123 views

### How to avoid complex terms in the results given by Integrate?

As shown by In1, integrating Sqrt[x^2 - 1]/(a + x^2) (1/x) returns a result with a complex terms; however, after I make a ...
0answers
184 views

### Unknown option PlotJoined->True [closed]

I am learning Mathematica (10.0) and tried the following code: ...
2answers
66 views

### For Loop in Mathematica {n, factored form of x^(n)-1} for 95<=n<=105

I am new to mathematica. I am trying to write a for loop to print out {n, factored form of x^(n)-1} for 95<=n<=105. I have followed the directions of another for loop, and gotten the following ...
1answer
124 views

### Prevent a sum from simplifying? [duplicate]

Basically, I want to prevent a sum from cancelling or summing together the individual summands and just display them separately next to each other. Example: ...
1answer
47 views

### Summimg peculiar nestings

I have some lists with peculiar nestings: ...
1answer
134 views

### How in Mathematica, would I define a function that takes arguments much like one would in an object orientated language

I would know how to write a function in object orientated language, just I don't know how to do this in mathematica, in an OOP I would define a function like this: ...
1answer
84 views

### Solving a complicated system

Could anybody please make a suggestion how can I implement this program which attempts to solve $2$ dimensional complex system of equations? My computer is not able to solve... After 3 hours the ...
0answers
52 views

### how can I manage the characters encoding of retun value from FetchURLWithHeaders?

I have retrieved a file from a web server by means of the FetchURLWithHeaders function. The retun value from FetchURLWithHeaders should contains the substring SCHØNHEYDER but instead I find ...
1answer
56 views

### How to query W|A, to get a list of asymmetric, bicubic and $3$-edge colorable graphs? [closed]

I'm interested in finding graphs with certain properties, like the smallest cubic bipartite asymmetric graph. While working on a related graph-theoretic problem, concerning edge-colrings, I came along ...
1answer
210 views

### Why can AppendTo modify a referenced list in-place but Part cannot?

Part, AppendTo, PrependTo, AddTo, etc. allow in-place modification of a list, but only Part requires that the list be referenced through a simple symbol, e.g. the following all does what you'ld ...
1answer
93 views

### How to obtain numerical answer for equation containing integration

Could some one tell me how to obtain numerical value of $a$ and $b$ from equations below: $$\frac{1+exp(b)}{1+exp(0.9a+b)}=0.95$$ $$\int_{0}^{\infty} \frac{1+exp(b)}{1+exp(a x+b)}=1$$
1answer
111 views

### Mean Preserving PDF Spreading

I have a histogram representing the PDF (probability density function) of an unknown discrete RV. The histogram is asymmetrical. Is there a known way in Mathematica to increase/decrease the variance ...
0answers
33 views

### Testing for a vector of all reals [duplicate]

I want to test if an expression is a vector of all reals. I defined RealVector[expr_]:=VectorQ[expr,NumberQ[#]&&(Head[#]===Real)]; Trying this on ...
3answers
558 views

### Finding all sublists or substrings of a given list/string

Given a list or string, how do I get a list of all (contiguous) sublists/substrings? The order is not important. Example for lists: ...
2answers
52 views

### Retrieve Options from function other than graphics objects

We can retrieve information about used Options for Graphics via: Options[Plot[Sin[x], {x, 0, 1}], "AspectRatio"] (* {AspectRatio -> 1/GoldenRatio} *) even if ...
2answers
129 views

### calculate missing values, Interpolation

I've following data: ...
3answers
127 views

### How to make $a1**a2** \cdots **an=0$ for a given $n$?

In order to optimize my computation and save memory, I'd like to modify NonCommutativeMultiply so that for a given $n$ one has $a1**a2** \cdots **an=0$ for any $a1, a2, \ldots, an$. To make it ...
3answers
179 views

### Localising OptionValues

The documentation on OptionsPattern leaves me with some unanswered questions. From the example section: ...
1answer
178 views

### How to properly apply NumericQ or s.th. similar here? - NDSolve inside NMaximize

I wrote a function that numerically solves a given Schrodinger equation and returns replacement rules to obtain the time evolution operator. It looks and is used as follows: ...
1answer
72 views

### How to put a fixed sized frame around traditional form expression

The height of a 2D form of a polynomial changes depending on the existence of exponents, fractional coefficients, etc. For use inside a Manipulate, I would like to ...
2answers
301 views

### Equivalent of Matlab's uigetfile in Mathematica

I was wondering if there an equivalent of the "uigetfile" Matlab function to use it in Mathematica. To be more precise, I want to read many Excel files and I don't want to type a static path; ...
3answers
105 views

### Testing for a vector of reals [closed]

Suppose I define: RealVector[expr_]:=VectorQ[expr,NumberQ[#]&&Head[#]===Real)]; Then: ...
1answer
130 views

### User Input Through Dynamic

For my application, I am using Dynamic functionality to make a number of input fields through which a user can enter numbers. I then take these numbers and place them as the entries in a dynamic ...
4answers
230 views

### accessing elements of nested list

I have a list of the form: toy = {{a, {b, c}}, {d, {e, f}}, {g, {h, j}}, {k, {m, n}}}; and would like to create the list ...
1answer
112 views

### Finding x when sin(x) = -.758 [closed]

I'm not understanding how to find all the angles for when sin(x) is equated to a negative decimal can someone explain to me how to find it..? So far I came up with 49.288 degrees, and 229.288 degree. ...
3answers
255 views

### Inconsistent image sizing with Grid and Row?

Can anyone explain why Row and Grid don't size the image correctly and consistently to 300 ...
3answers
513 views

### How to create a Disk with smoothly changing coloring?

I want to have a disk. But this disk shouldn't have a fixed color; instead, I'd like it's color to fade smoothly. Until now, I came up with two ideas how to achieve this. Idea #1: ...
1answer
168 views

### How to sample only odd numbers in the domain of a table for list plot [closed]

The following code samples $k$ points around a circle at integer values starting from $0$: ListPlot[Table[{2 Sin[(2*y/x)*π*n] , 2 Cos[(2*y/x)*π*n}], {n, 0, k}] I ...
0answers
59 views

### How to Fold (FoldList) this in a more compact (efficient) way?

Example code: x = Table[something[i], {i, 5}] Table[Fold[f1[#1, f2[#2, a], a] &, x[[i]], {c1, c2, c3}], {i, Length[x]}] This above is just an example. I ...
1answer
148 views

### Incorrect use of Scaled causes crash

Bug introduced in 8.0 and fixed in 10.1.0 While playing with Scaled, I made a syntax error which caused a crash instead of an error message ... Do you get the ...
0answers
98 views

1answer
67 views

### Series expansion of large expression

I have the following equation: eq=E0[x,y,z]+E1[x,y,z]*Cos[phi]+E2[x,y,z]*Cos[phi]^2+E3[x,y,z]*Sin[phi] Now E0,E1,E2 and ...
1answer
71 views

### How to use a list of rules as a data set

I have a file of models that I have saved that I want to be able to call in another program to be solved with NDSolve. Can I use ...

15 30 50 per page