# All Questions

117 views

### How can I simplify the result of a differential equation by using my own defined expressions? [duplicate]

I want to solve the following differential equation with mathematica: α β * w''''''[ξ] + ( 1 + α - p ) * w''''[ξ] + p/β * w''[ξ] = 0 The answer seems at ...
288 views

### Solving a nasty partial differential equation

I have a differential equation that I would like to solve numerically in the region $z \in [0,L]$ and $t \in [0,t_{max}]$: $$\partial_t S(z,t) = f(z)S(z,t) + \int_0^L \text{d} z'g(z,z') S(z',t),$$ ...
28 views

### How set input font globally? [duplicate]

I'm trying to change input font in default.nb, but font font not changed, changed only font size. I'm also try set StandartForm style, but nothing happens. In preferences/Evaluation style of newly ...
758 views

### Creating the Nabla operator as a operator

How can I define the nabla-operator as a an operator, acting on everything to the right of the operator! Also taking \[Del]^2 would give the second derivivates. I wish to be able to write \[Del]f[...
97 views

### Making a movie from an interpolating function

Say I use some Mathematica procedures to find an interpolating function of two variables: $u(x,t)$. Is it possible to make a movie of this interpolating function, i.e. plot it on a certain line \$x \in ...
70 views

### How to assign the values for the Table list?

Now, I want to assign some values for a Table list and I find that If {mat[1], mat[2], mat[3], mat[4], mat[5]}={4,23,3,12,1}; it is no problem. But, if we use ...
105 views

### how to change the name of exporting file automatically

I want to export some sort of data from Mathematica to .txt files but every time with a different name.clearly I want the name of files change automatically in each loop for each series of data that ...
42 views

### Bug? Kernel Crash on SparseArray access [duplicate]

Bug introduced in 5.2 and fixed in 10.1.0 The following simple code s = SparseArray[{}, {10, 10}] s[[1, {1, 2, 3, 1, 1}]] = {a, b, c, d, e} on my machine (...
1k views

### The magic square function

There're some matrices that the sum of columns, sum of rows, and sum of diagonals are the same value. Here is an example: ...
662 views

### How to generate logarithmic/ Trigonometric tables in mathematica

I was looking for ways to create logarithmic / trigonometric tables in Mathematica. And printing them for use . Here the tables should be like standard log tables with mean differences column . I don'...
116 views

### How to get the raw data of solutions of partial differential equation in mathematica

I am using NDSolve command of mathematica solving a very complicated partial differential equation (two independents "t" and "x", three master variable "u", "v", "w"). Each time I solve it, it takes ...
241 views

### How to merge permutations obtained from Solve on multiple variables?

When I compute the following expression to find integer solutions of the equation (x^2 + y^2 + z^2 == 14^2) ...
83 views

### How to solve these equations by Mathematica?

l tried it with Solve,DSolve and NDSolve functions,but all failed.Should l simplify the equations in the papers or use other mathematica functions.Thanks~
106 views

### deployment from programming cloud

Can anybody help. I can't get the simplest notebook (see code below) to deploy. I upload the notebook to my Wolfram Cloud account. Click deploy. Copy the link and send it to my sister. She can ...
499 views

### Creating a fast random array generator

I want to create N x N array of random numbers. (N is an integer). The constraints are, each element should be between 0 to l(integer) ( here 0<= l <= N) and the sum of elements in each row ...
1k views

### RSquared: LinearModelFit vs NonlinearModelFit

I'm trying to understand the differences between LinearModelFit and NonlinearModelFit. One thing I notice is that the ...
232 views

### Sort two lists at the same time, based on another

I am new to using Mathematica and I can not find a solution to what I am wanting to do. I want to take a list such as: x = {1,2,3,4,5,6,7,8} and a second list (...
121 views

### How can I programmatically call MUnit tests in Wolfram Workbench?

I have a collection of .mt test files in Wolfram Workbench. Is there a way to invoke the tests programmatically and then write the results to a text file for ...
240 views

### Trace one point's coordinate values in sequentially images

I am a research student in a university. I think I need some help. I used a video camera to monitor the vibration of a plank. Then I should calculate the amplitude and frequency of the vibration ...
239 views

### Using Placed with Show - the simplest solution to move the legend around?

Please let me know if this is a duplicate. There are some solutions, but I think there must be something simpler for this kind of situation. ...
248 views

### NSolve & PrecisionGoal

I am using NSolve to find numerical solutions of a particular equation. I do not need the solutions to as high of a precision as the other numbers in my notebook. To improve run time (I am iterating ...
147 views

### Can I sum or mulitply 2 columns in a list of associations

I have a list of associations. I will need to add 2 columns (or perform some other arithmetic operation) and put the answer in a new column. For example: ...
208 views

### How do you graph the confidence intervals that results from a GARCH over a time series?

Please, does someone know how to draw a confidence intervals (from the results of a GARCH (1,1)) in a way similar to these: *Asume an ARMA(1,1) fit the time series. Thank you very much
202 views

### How can I model the volatility, using a GARCH(1,1), of a time series of returns (and plot it) using Mathematica?

I know that if I use this code: tsm = TimeSeriesModelFit[ret, {"GARCH", {1, 1}}]; I can get the parameters using this: ...
203 views

### SymbolicC Simplified Displayed

How might I display a simplified SymbolicC below. For example in the following example ...
313 views

### What method does NIntegrate use by default?

There is a variety of algorithms for performing numerical integration (See wiki). What method does NIntegrate use by default? I looked at the documentation page ...
45 views

### Output form of a result [closed]

Suppose I computed something with Mathematica, and the result is in the form Gamma[1 + N]^2 How can I tell Mathematica to write the result in a more ...
256 views

### How to determine reason for kernel crash? -> Nelder Mead optimisation

I am making use of the Nelder Mead algorithm inside Mathematica's NMaximize to find a parameter set by solving the Schrodinger equation for a given system. (see ...
291 views

### How to formally tell if one time series affects another?

In time series analysis, a correlogram, also known as an autocorrelation plot, is a plot of the sample autocorrelations. I'm rolling my own now and I'm not a statistician, but I think this sort of ...
95 views

### Third-order ODE with NDSolve

I would like to use NDSolve to draw the integral curve of a third-order ODE ...
238 views

### NDSolve with initial condition: initial conditions did not evaluate to an array of numbers of depth 1(for 1D) or 2 (for 2D) on spatial grid

I have the following naive code to solve a PDE in two spatial dimensions (x,y) with periodic boundary conditions: ...
131 views

### Maximizing the number of zero entries in a matrix

I have a matrix with a bunch of parameters in its entries, they all come in different combinations in different places of the matrix. I can post the matrix itself if requested, but I think what I mean ...
534 views

### Is there a way to identify a symbolic fraction?

Is there a way to use Head to detect a symbolic fraction? In particular I find, Head[a/b] Head[1/5] Times Rational ...
105 views

### Why doesn't ToString work in ReplaceAll? [duplicate]

I'm trying to use ReplaceAll in a subscript. However, it doesn't seem to work as expected if I want to use the output the subscript in a ...
16 views

### Use of placeholders in functions [duplicate]

I'm having some trouble with Mathematica's placeholders within functions. The function sel[lowerLimit_] should select all elements of x that are greater than the lowerLimit: ...
220 views

### Shorthand for operations?

Mathematica has a large number of built-in symbols, and I am unsure when there is a shorthand for the operation I am trying to perform. Question 1: Is there a shorthand for the function ...
89 views

### Mathematica & Statistics? [closed]

So, let's say you flip a coin 10 times, and call that 1 "event". If you run, 1,000,000 of these "events", what is the proportion of events that have heads between 0.4 and 0.6? Binomial probability ...
120 views

### How to convert cube root of this equation into TeX?

When I solve the equation $$\sqrt[3]{-3 x+6}+\sqrt[3]{2 x+4}+\sqrt[3]{x-10}=0$$ I used ...
154 views

### DSolve for Second Order Differential

I have an equation y''[t] + w^2*Sin[y[t]] == 0 So I'm using DSolve like this: ...
39 views

### Indent SymbolicC [duplicate]

What is they shortest way to automatically indent SymbolicC at the Brackets { and }? For example: ...
83 views

### Solutions to multivariate equation

Is there any way to get Mathematica to give a set of solutions (pairs of x and y that are integers) to an equation with multiple variables? Something like: ...
134 views

### How to filter acoustic signal

I have a huge data file which I can't ListPlot. This code generates similar kind of data: ...
155 views

### How to automate repetitive evaluation of a notebook from a parent notebook [duplicate]

I've got a code that I want to automate, but I'm not sure how. I have a Mathematica notebook that I need to run many times over, each time changing one variable and repeating. My idea was to set up ...
145 views

### Can Mathematica return the first few terms of a sequence given the first few terms of a Dirichlet Generating Function?

For example: a=Sum[1/n^s,{n,1,6}]; Expand[a^2] returns a big mess. I want to see something like: 1/1^s + 2/2^s + 2/3^s + 3/4^s + 2/5^s + 4/6^s + ... + 1/36^s.
1k views

### Creating a realistic, photo-like 3D effect from an image or document

Suppose I have an image or a document, provided in a high-quality PDF file. You can open and view it in a PDF viewer, but then it has a kind of static look: it's not something tangible, it's just an ...
57 views

### NonlinearModelFit not hunting for good values

I have the following data which come from complex values but I have turned them into a 3D list ...
97 views

### Efficiently plotting a function with its translates?

How does one efficiently produce a plot of {f[x], f[x]+1}? Assume that f[x] is a long computation, which I would like to avoid ...
157 views

### Computing Poincaré symbolic solution for an arbitrary integer order polynomial

In the 1880s, Poincaré created functions which give the solution to the nth order polynomial equation in finite form. These functions turned out to be "natural" generalizations of the elliptic ...