# All Questions

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### Improving performance in the generation of random (directed acyclic) graphs

I need to generate large (directed, acyclic, transitive) graphs. My code in Mathematica gets very slow for large numbers of vertices. I've tried a number of approaches and I can't find any significant ...
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### Render dynamic Graphics objects static

As was discussed in the comments of another question (MathLink Graphical Output (Plots) to File), Graphcis objects produced by commands such as ...
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### How to combine multiple functions into a single function, indexed bya new argument

I have a system of expressions (matrices) which correspond to increasing orders of precision in a theory. These expressions are quite complex (require about 40+ lines of code to produce) and are not ...
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### How do I NOT change the input/output number when editing?

I tried to search for a topic on this, but didn't seem to find anything, so here goes. I'm pretty new to Mathematica, so there are a lot of things I don't know yet, but one thing is pretty annoying ...
556 views

### Why does Simplify[b-a] give -a+b and not b-a?

Simplify[b - a] results in -a + b. I prefer b - a, which is a bit simpler (3 symbols instead ...
55 views

### Using IntegerPartitions for distinct integers

What I would like to do is to find a way to test how many ways m distinct integers from the set {1,..., n} where ...
116 views

### Fast way to get positions of “boxed” array elements?

Given a 2D array (arbitrary numeric / evaluates to numeric elements, simplified for examples, and can be arbitrary dimensions so long as the operation makes sense, I'm working with 2K X 2K in my ...
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### Summing Over a Variable Number of Indices

I am trying to figure out the best way to include a variable number of indexes of summation in a program. For example: Suppose I want to define a function $g[n,s]$ that returns the sum ...
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### The output is the same as Input when I add the boundary conditions to a PDE

I am trying to solve a PDE in the first order with specific boundary conditions. When I solve use DSolve without the boundary conditions, Mathematica gives me an answer in an arbitrary function. When ...
165 views

### Font Issues: “Like Resource 58” error

I'm running Mathematica 9.0.0 on a Macbook Air with OSX 10.6.8 and I've recently started having issues with the font in the program. All special characters are being replaced with other characters in ...
43 views

### Simulation code performance tuning

The following simulation takes over 20 seconds for evaluation. I have difficulty re-coding it with Nest and Map or Compile functions to make it more efficient. Can some one help with this? The ...
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### Arguments for ChartElementFunction

I was reading the documentation for BubbleChart and I saw this example ...
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### i do not understand why NSolve::ivar error is occouring? [duplicate]

PLEASE HELP v[t] = Sqrt[(x'[t])^2 + (y'[t])^2 + (z'[t])^2] NSolve[{z''[t] == -9.8 - 0.0154 z'[t]*v[t], y''[t] == -0.0154 y'[t] v[t] + 0.0033 x'[t] v[t], x''[t] == v[t] (-0.0154 x'[t] - 0.0033 ...
39 views

### combining manipulate with “static” plot

Is there a way to show a plot of a "static" function as background for a manipulate panel ? In other words: I have put into a manipulate a trajectory (solution of a system of two differential ...
73 views

### Resizing graphics with an inset when exporting

I am generating a number of graphics using Mathematica that contain text. Adding the text to the graphic has been a considerable challenge, but I have finally come up with the following: ...
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### MLEvaluate() Function Gives Error

I am trying to link my C++ program to Mathematica Kernel. I am trying to use the MLEvaluate() evaluate but I receive an error while compilation. My codes are as below: ...
43 views

### Combinations rather than Permutations? [on hold]

Is there a systematic way to generate the following. Let's say I have 8 variables vars={a,b,c,d,e,f,g,h} I want to access all combinations of 1 variable, ok, ...