# All Questions

129 views

### How to simulate a multivariate recursive system from a list

New to mathematica, trying to use Eric Swanson's Pertubation AIM program to solve DSGE models. His code produces a solution as a list or a table. My question is how do I use this list to simulate the ...
242 views

### Utterly confounding behaviour in Mathematica 9 DSolve

I've been baffled by a lot of the behaviours of Mathematica 9 — so much that I regret upgrading my copy of Mathematica 8 (I would downgrade but I'm currently on vacation). Here is an example: ...
116 views

### Incorporating a Manipulation in an Animation

I am having trouble incorporating a manipulation into my animation. I want to be able to maniuplate the 5 constants at the beginning. Am I going to need to combine all of the code into one string? ...
229 views

### How to scale edge length and keep layout of edge-weighted Graph?

I love using Graph as structure to store and visualize my data in Mathematica. Consider the following simple example for creating a ...
173 views

### Style markers in strings

I'm dealing with strings in Mathematica and I would love to handle their stylling in the most cenvenient way. Without loss of generality, let's assume I want to make some parts of string ...
914 views

### Find the slope between adjacent points in a list

I have a list of two dimensional points that are ordered by their x-coordinate. I would like to calculate the slope between all adjacent points. I'm familiar with the use of pure functions in Sort ...
192 views

### Using new symbol in WhenEvent in NDSolve

This is an example in Mathematica's help document. ...
950 views

### List of dangerous functions

I no longer believe it is a good idea to work with a list of dangerous functions. I have tried to edit the question is such a way that it respects my earlier perspective, but also so that it does not ...
600 views

### The underlying process of Integrate[] [duplicate]

Integrate[x^4 E^-x^2, {x, 0, +∞}] Output: (3 Sqrt[π])/8 Can someone explain to me the specific calculation process ?
1k views

### Linear programming with many variables and parameters

I am trying to reconstruct the answer that is given in this report. (page 153 in Appendix B; Section B.2.1). They are given variables, parameters, constraints, and the objective function to minimize. ...
140 views

### Using Select on list of vectors [duplicate]

I have a dataset, where each element in the list is a vector as in data = Table[{i, 2 i, 3 i}, {i, 1, 10}] As an example, I am interested in the entries where ...
339 views

### Mathematica inserts extra \left and \right for absolute values in LaTeX output

Type the following in a Mathematica DisplayFormula cell(other styles may also encounter this problem): Esc+l+|+Esc and Esc+r+|+Esc, and save as LaTeX. Note: See the difference of the character ...
333 views

### Symbolic integration fails while numerical integration succeeds

I am hoping to evaluate the following integral Integrate[((r^3 - 7)^(2/3)*(1 - (r^3 - 7)^(2/3)/r^2))/r^3, {r, 2, Infinity}] but Mathematica informs me that this ...
1k views

### Simplifying expressions with square roots

I would like Mathematica to simplify this expression: $4 \left(16 \sqrt{\left(-1+2 c^2\right)^2}-32 c^2 \sqrt{\left(-1+2 c^2\right)^2}+\sqrt{\left(1-8 c^2+8 c^4\right)^2}\right)^2$ ...
55 views

### Export and Import with graphics characters

I exported a list of characters say: Export["hello.txt", {t, r, $\theta$, $\phi$}, "List"]; the file has the correct symbols when opened with a text editor, however, when I imported it with ...
109 views

### Evaluation of elements in a list and then sorting them

This is probably a simple problem, but I'm having a lot of issues with it because I'm unfamiliar with Mathematica syntax. I have a list ...
169 views

### The Flat Attribute, Unevaluated and the Evaluation Process

To make this question easy to follow let's give some symbols a couple attributes. Attributes[f] = {Flat}; Attributes[s] = {Orderless}; Now consider the ...
187 views

### Autoupdate Dynamic Variable and Selectable

Does there exist a technique to construct a Cell that allows you to both auto update a Dynamic variable and allows you select the code while the variable is being ...
425 views

### Removing the edge features of an image while enhancing internal connectors

I picked up the following leaf today while going for a walk. And wanted then to run the same analysis that @Vitaly Kaurov did for rivers under this posting Measuring Fractal Dimensions of natural ...
231 views

### Partitioning a superset of coordinates into subsets that generate continuous curves

Consider the data set corresponding to recorded trajectories for a particle: ...
496 views

### How can I calculate the perimeter of an equation-defined curve？

This is how the curve looks like: ...
137 views

(My code:) ...
268 views

### Color inversion using ArrayPlot

I have a 3D data that I want to visualise its each slice with ArrayPlot. However, there is a problem the way it represents the data. As, ArrayPlot by default generates grayscale output, in which ...
387 views

### How to make a conditioning plot?

I'd like to make a conditioning plot just like coplot in R. Is there a pre-made solution or do I have to make a bunch of plots individually? Edit: This is an example from r screenshots. It is a way ...
398 views

### Exception/Error handling using returns codes

There is good explanation available for error handling on this and similar links. Here there is information on handling inappropriate input arguments and handling unprocessed functions using ...
451 views

### Generating a “best fit” curve to a set of noisy data corresponding to a moving object

Please note that this is an extension of a previous question: Interpolating a sparse list of two-dimensional coordinates We have an ordered array of coordinates corresponding to the position of an ...
179 views

### Interpolating a sparse list of two-dimensional coordinates

I've run into a problem where I have an ordered array of sets of coordinates, for example: ...
223 views

### Is there a fast method of generating a Standard Deviation image from a frame stack?

Imagine I have a stack of image frames, $(f_1, ..., f_N) \in F$, where each $f_i$ has the same set of $(x,y)$ dimensions. Using these frames, I'd like to create an image where each pixel in the image ...
176 views

### Series resulting in “No more memory available.”

Is there any way to force Mathematica to come up with the closed form to Sum[1/(i^18 (i^2 + j^2)), {i, 1, Infinity}, {j, 1, Infinity}] or ...
380 views

### Problem with Fourier and InverseFourier function

I have the following code Image[img, ImageSize -> 300] data = ImageData[img]; fdct = Fourier[data] tdata = InverseFourier[fdct]; Image[tdata] but it seems to ...
405 views

### What is the real default CellEvaluationFunction?

The default CellEvaluationFunction is Identity but one can quickly see that this is handled specially as an equivalent function, ...
213 views

### How to fold output cells by default?

In Mathematica the default behavior of output cells is to pop up after the kernel has processed the input cells and got a result. I know I could add ; in the end of ...
212 views

221 views

### URLFetch functionality for a Persian website

I want to fetch the content of a Persian website. I tried URLFetch["http://www.tsetmc.com/"] Why is Mathematica unable to recode the characters in the results ...
598 views

### PDF of binomial distribution and mixed binomial distribution

I want to plot the PDF of binomial distributed function and a mixed binomial distributed function, therefore I entered for the binomial distribution function the following: ...
537 views

### Problems with “Test Connectivity” and the Pacletserver

I know there has been a similar questions to this already but the solution did not work for me so here again: I have internet connection and I can execute such commands like: ...
390 views

### Placing a zero at coordinate center when plotting with Ticks -> None

I'd like to plot a certain function where only its qualitative progession shall be emphasized. Thus, using the Ticks->None option seems to be appropriate. ...
74 views

### How can I get a horizontally centered input window?

This example displays a input window at a position of 675 from the left. ...
236 views

### Is it possible to separately call the default value of a variable which isn't at the end of the sequence?

After reading this post I recalled an old question I once met. We know that we can set default values for variables of a function: ...
722 views

### Is there any way to define pure functions with optional arguments?

For example consider the following function: Function[{u,v},u^2+v^4] Is there anyway to define default values for the variables ...
3k views

### Determine the 2D-Fourier transform of an Image

I am new to Mathematica and using Version 8.0. I want to calculate the 2D-Fourier Transform of a digital image and see its Magnitude and Phase Spectrum, and reconstruct it.
167 views

### Compile error from If but not from Piecewise

Consider this: point={1.,2.}; f1 = Compile[{{t, _Real}}, Evaluate[Block[{a, b}, {a, b} = point; If[t > 0., a*b*Sin[t], 0.]]]]; f1[2.] ...
### How can I eliminate $x_1$ from my two ODEs?
How can I get Mathematica to eliminate $x_1$ in the equations in the first box to achieve the equation in the second box？ My code: ...