# All Questions

572 views

### I failed to solve a set of one-dimension fluid mechanics PDEs with NDSolve

@DNA The fluid here has been assumed as single component perfect gas i.e. it obeys the equation P=ρRT, the thermal conductivity is assumed as a constant, so the equation is: ...
275 views

### The gap between MapAt and ReplacePart for 2D data tables with headers

Consider a relational table derived from survey data, where each column ("001-01" ...) represents a responder and each row (...
251 views

### Can JavaScript query the actually used dimensions of an HTML embedded CDF?

I have an HTML embedded CDF on my website. The size that is actually being used up by the single manipulate in the CDF changes when you use the CDF; you can make more sliders appear, and then it will ...
440 views

### Convert Graphics3D containing BSpline to polygon primitives for export to 3DS?

Graphics3D[] objects created with BSpline functions will not export to 3DS format, which only supports the more basic primitives. Is there any straightforward way ...
484 views

309 views

### Multiple simultaneous events in EventLocator method for NDSolve

I'm using NDSolve to integrate a system of ODEs, and EventLocator to stop the integration when it leaves a certain region in phase space. This works perfectly as it should. However, I've also added ...
1k views

### Remove image background of headshot in Mathematica?

For example, using ExampleData[{"TestImage", "Girl2"}]: what's a general way to make the background transparent? I've tried various combinations of ...
230 views

### Dynamic lists as function arguments

Suppose I have a function that requires a list is as input. I.e. f[list_]:=DoSomethingWithList Now, if I pass a variable as Dynamic like this ...
145 views

### How to change type order in PearsonDistribution?

I need to estimate a Pearson distribution from a batch of tables tab: ...
571 views

### Controlling the 2D $x–y$ aspect ratio of a 3D plot

I have some data representing a nested list, each element being composed of 3 real numbers like ...
505 views

### Adapt ColorFunction in Array Plot

The problem I'm facing is how to adapt ColorFunction so that it ranges from green (low values) to red (high values): ...
633 views

### 3- dimensional plot of 2-dimensional systems of differential equations

Let's take this first example of a 2D output: ...
653 views

### AccuracyGoal, PrecisionGoal, WorkingPrecision and NDSolve

I'm trying to understand exactly what WorkingPrecision, AccuracyGoal and PrecisionGoal mean ...
431 views

### Can you call a C function that takes function pointers as arguments?

I want to use MathLink to call a function I wrote in C. However, similar to an integrator, it takes a function pointer as an argument and applies it on numbers depending on the other arguments. I ...
426 views

### Visualize cluster distances in DendrogramPlot

I want to perform a cluster analysis using the HierarchicalClustering package. Is there a way to display the inter-cluster distances in a dendrogram plot? An ...
172 views

### Why didn't Reduce give me the right result?

My code: Clear[r1, r2]; par[r1_, r2_] := r1 r2 / (r1 + r2); Reduce[{5 par[r2, 32000]/(r1 + par[r2, 32000]) == 1.8 && par[r1, r2] == 5000}, {r1, r2}] ...
157 views

### Can individual locators in LocatorPane be temporarily disabled?

This follows up on another question about the sensitivity of Locators in a a LocatorPane. I would like to be able to enable/disable individual locators in a LocatorPane. In the simplified version of ...
840 views

### Solve matrix equation A*X=X*B using LeastSquares

I want to solve matrix equation A*X=X*B using LeastSquares method, but it is suited for equation like A*X=B. All matrices are 3x3 ...
1k views

### Find the dimensions of a cylindrical can that will minimize the cost of the material

A cylindrical can is to be made to hold 1 L of oil. Find the dimensions that will minimize the cost of the metal to manufacture the can. This is a standard calculus problem. The volume of the ...
126 views

Recently I have been working on group theory and I have found checking for associativity for specific Cayley tables to be rather tedious so I wrote a program to do it for me. Most of the time I would ...
244 views

### Polynomial expectations of generic distributions

Summary Polynomial expectations depend only moments and cross moments of a multivariate distribution. I would like to use Expectation to compute polynomial ...
368 views

### Word Squares and Beyond

A word square is a set of words which, when placed in a grid, read the same horizontally and vertically. For example, the following is an English word square of order 5: ...
868 views

### Animation of Differential Equations from NDSolve with ParametricPlot3D and Evaluate

I have a system of differential equations (referred to as "s") and use NDSolve to obtain the solution. I substitute the interpolated functions for the original ...
155 views

### Efficiently importing XPM matrix data into Mathematica

The XPM file format is an image file format. Although it is primarily intended for icon pixmaps, it can also be used to store matrix data. For example, the GROMACS chemical simulation package uses ...
144 views

### How to get the boolean value of an inequality involving an InterpolatingFunction?

Here's the code: yan = FunctionInterpolation[x^2, {x, -1, 1}]; FullSimplify[yan[x] > -1, -1 < x < 1] Needless to say, what I expect to see in the output ...
1k views

### How to use filling in ContourPlot

I want to fill region between different contours, e.g. ContourPlot[{c1 = f1, c2 = f2}, ...] a la the filling options for Plot ...
### What function can I use to evaluate $(x+y)^2$ to $x^2 + 2xy + y^2$?
What function can I use to evaluate $(x+y)^2$ to $x^2 + 2xy + y^2$? I want to evaluate It and I've tried to use the most obvious way: simply typing and evaluating $(x+y)^2$, But it gives me only ...