# All Questions

87 views

### Plot producing many error messages when given complicated function

I'm new to Mathematica and am running in to all sorts of silly difficulties with coding in it. I'm trying to calculate a function f[x, k], normalise it with another ...
288 views

### Draw plot with locator & slider

I would like to create a plot whereby both the slider and the locator 'draw' the plot. In the following code, the locator & the slider act independently: ...
215 views

### Visualization of iteration procedure in NMinimize

I have this optimization code: ...
120 views

### Strange behaviour of InternalInheritedBlock

I was going to post an answer for fast way to replace all zeros in the matrix. I was even quite happy because timings were the same order of magnitude as others. The idea was to overwrite ...
80 views

### What's wrong with my implementation on CountryData

I was wondering, *for which countries is the proportion of Phone line users to population greater than or equal to that of the United States?* This is what I inputted below, but the list of countries ...
13k views

### MathLink linking error after OS X 10.9 (Mavericks) upgrade

After macosx 10.9 mavericks upgrade i have a compilation problem, you can see below. Even the examples given in ...
249 views

Given: ...
278 views

### Import symbolic variables from Matlab with MATLink

I'm trying to manipulate with Mathematica symbolic expression created in Matlab. I'm using the MATLink package, and I've succedeed in importing numerical variables, but not symbolic ones : ...
678 views

### Solve a PDE on a domain $\Omega$ with given boundary conditions

I'm starting to study the behavior of some PDEs and I would like to run simulations in mathematica to help me visualize solutions. For example, a prime example that I would like to study is  ...
114 views

### Esc-esc for special characters and autocomplete in Mathematica 9 [duplicate]

I recently upgraded to Mathematica 9 and have noticed a slightly annoying behavior that I was looking to remedy. In the past I would type special characters, e.g. ...
652 views

### Plotting multiple lists of complex numbers

The user #Nasser showed an elegant way to plot complex numbers: ...
332 views

### What is the fastest way to replace all zeros in a matrix?

In the following matrix m every 0 should be replaced with a 1: m = {{0,1,2},{5,0,3},{8,0,0}} Desired result: ...
424 views

### How to I display the value of my plot function?

I've plotted a function that varies with respect to time. It's inside a manipulate box, which can vary the time. And I'd like to display the value of the function at the time on the slider on my plot. ...
2k views

### How can I plot implicit equations?

If you enter the following into Wolfram | Alpha, you get nice graphs: graph 4 x^4 + y^2 = 2 How do you do this in Mathmatica? I realize that these are not ...
371 views

### Import an SPSS, SAS, or STATA file into Mathematica

I would like to import the World Value Survey data file into Mathematica, but it's only given in spss, sas or stata formats, which are statistical analysis softwares format I think. I can't get to ...
452 views

### NIntegrate & non-numerical values

I am wondering why I am receiving the message "The integrand ... has evaluated to non-numerical values for all sampling points in the region ..." for a particular calculation I am running. How can I ...
179 views

### How can I mix colors?

As far as I know if you combine Blue and Green the result is Cyan (using additive mixing). ...
254 views

### Random Matrix with integer coefficients and inverse also having integer coefficients

I'm trying to build a function that gives me matrices such that each: Has integer coefficients. Is non singular. Has inverse which also has integer coefficients. I have some code that one of my ...
202 views

### Visualizing nested lists for easier human understanding

When interacting with Mathematica, I often find myself staring blankly at waves of curly braces, trying to understand how data is organized hierarchically. For example, the beginning of the result to ...
453 views

### Simulated Annealing InitialPoints option

I have a cost function that depends on 4 parameters: CostFunction[{tx,ty,tz,ox}]. I used NMinimize[] function with ...
224 views

### Solve[polynomial, x, Reals] doesn't get all real roots or correct ones?

My main confusion is about the difference between the two code blocks at the end of this long spiel, but the spiel contains the code to create the polynomial if its coefficients are helpful for ...
91 views

### NMinimize memory consumption problem in Mathematica 9 vs. 7 & 8

I am having trouble using NMinimize in Mathematica 9 - Memory consumption overflows. The same NMinimize command, with the same ...
204 views

### plotting an Integration output

How to solve this integral by Mathematica even by numerical methods (plotting the solution) Integrate[(Cos[x] - a)/(1 + a^2 - 2*a*Cos[x])^1.5, {x, 0, 2*Pi}] It ...
87 views

### Missing something in my input for CountryData dependencies

I'm trying to find (a)which countries have dependencies (b)and a list of countries that consider themselves dependencies (c)and a list of countries that don't consider themselves dependencies. ...
337 views

### Gamma Incomplete Function representation in Mathematica and Matlab

I am confused about Gamma Incomplete function calculation in Mathematica and MatLab: For example, in Mathematica: Gamma[5,3] = 19.56 But in MatLab: ...
110 views

### Unit ratio in plots? [closed]

I want to make a plot in which unit interval on both axes to have equal lengths visually. i.e. I want (1,1) and (0,0) to make a square rather than an elongated rectangle.
254 views

### Problem importing a JCAMP-DX mass spectral file

I have some problems importing a JCAMP-DX EI-mass spectral file using Mathematica 9. For example, if I download the mass spectrum of nonacosane in JCAMP format from NIST, ...
123 views

### Manipulating and using result of DSolve

I have an unsightly looking equation that nonetheless has an analytical solution. The solution is ugly as hell, but exists; I use the following code with the DSolve ...
742 views

### ArcTan[z] and ArcTan[x,y], Restriction and Conversion

In Mathematica there are two different forms for the arctangent (inverse tangent), namely ArcTan[x,y] which gives the arc tangent of $y/x$, taking into account ...
221 views

### Why is this expression being held, and how can I evaluate it?

I can't figure out why an expression isn't evaluating, even though there's no Hold* in its FullForm: ...
188 views

### Where did I go wrong with my implementation of finding a plane tangent to a surface?

I am working on finding the plane tangent to a paraboloid at a given point. My code: ...
148 views

### DSolve expression not evaluating

I entered the following into Mathematica: p[x_] := 4 x q[x_] := 4 Sqrt[x] - 3 f[x_] := E^-Sqrt[x] DSolve[y''[x] + p[x] y'[x] + q[x] y[x] == f[x], y[x], x] ...
200 views

### When does the real part of Zeta vanish on the critical line?

This seems to be a quite a simple problem but I cannot make it work. I am trying to find all values within a given range for which the real part of the Zeta function vanishes on the line: ...
264 views

### How to effectively compare two sentences and say both are equal

want to compare two text file. Suppose file AA contains following text ...
241 views

### Efficiently searching a list for the position of the closest number to a specified number

Searching by closest and position I wasn't able to find an answer—but found Nearest by guessing. Nearest, however, returns ...
150 views

### automatic processing of numerical results in Plot`

First I want to solve an equation $F(x,y)=0$ for $y$ by supplying a value of $x$. (suppose obtaining the analytic form of $y(x)$ is too difficult) Then I want to plot root $y$ (numerically calculated) ...
190 views

### Recurrence relation: Find a recurrence and evaluate (on WolframAlpha) [closed]

I am trying to get WolframAlpha to solve a recurrence and evaluate a result in one query. For example: If ...
141 views

### Plot3D missing a zone

I am trying to plot a simple graph using Plot3D: ...
264 views

### Assigning an analytical approximation to the error function erf(x)

Working with some iterative integral equations I have Gaussian density functions involved therein. Integrating the gaussian function I obrain the error function. When I take the second integration, ...
99 views

### Function generating a rule with a Patterns: e.g. toRule[ lhs, rhs] into lhs[x_] -> rhs [duplicate]

I want to create a rule as a function of z from a left and right hand side. My (non-working) code and usage is: ...
84 views

### Display Part Of or Summarize Other Notebooks

How might I display parts of(or basically summarizing) one Notebook from parts of several other Notebooks? This isn't a strict question question but more of a general/wiki question of how to organize ...
304 views

### How Can I superpose an image and a graphics?

I want to superpose an image with a graphics in order to evaluate their alignment. I am writting this exemple of code. ...
556 views

### Is LinearSolve the most robust way to solve the equation $Ax=b$?

I want to solve the equation $Ax=b$, where $A$ is an $n\times n$ matrix, and $x$ and $b$ are $n\times 1$ column vectors. Here $n=124$. LinearSolve[A,b] I got the ...
218 views

### using index notation for finite differences

I am interested in deriving finite difference equations, which means I have to play around with indexed quantities. For example, for a 2D function f(x,y), I could discretize it on a grid with grid ...
132 views

### Problems with formatting a bar chart

I am trying to create a financial dashboard using Mathematica. I am having trouble formatting the axes ticks to show whole numbers. Further, when I hover over one of the chart elements, it is ...
184 views

### No Speedup Compiled Function in FindMinimum

The problem: I would like to minimize an objective function with respect to 12 variables. Minimization should be executed as fast as possible. Compiling the objective function increases the execution ...
130 views

### Texture[] not working properly with Image AlphaChannel

I recently encountered a problem when combining multiple texture layers in an graphics object when the texture comes from an image with alpha channel. Apparently the alpha channel of the image passed ...
33 views

### Pattern matching list elements in pure functions [duplicate]

Pattern matching here is a functional programming term, but it might be called differently in Mathematica, I'm not sure. It is possible to match the elements of the list in a regular function ...
### How to compute MIN$(A(x), B(x))$
I have two polynomials: $\;A(x) = \sum a_i\;x^i$, $\quad B(x) = \sum b_i\;x^i$. Given $A(x)$, $B(x)$, I want to compute $\;C(x) =$MIN$(A(x), B(x)) = c_i\;x^i$ where $c_i =$MIN$(a_i, b_i)$. How can ...