Questions about the use of built-in Mathematica functions, including pure functions.
5
votes
1answer
92 views
Does pass-by-value affect the performance of function calls?
I only have a little coding experience in C, and I remember I was told that pass by reference is more efficient than pass by value since the parameters don't need to be copied. Since there is no pass ...
4
votes
3answers
291 views
Simplify function notation
I have some calculations with arbitrary functions. In the output, Mathematica always shows the functions with its arguments. I would like to tidy the notation a bit, by hiding the arguments in the ...
4
votes
3answers
222 views
How to cancel floating point factors?
I am currently having problems with some floating points.
I have a function, which gives as an intermediate result (for example)
...
12
votes
1answer
353 views
Error checking and trapping techniques with Throw and Catch
Mathematica provides several mechanisms for checking arguments and trapping errors in a function definition.
Typical methods are :
Definitions with argument patterns, definitions with ...
9
votes
2answers
227 views
Sum or Product with Exclusions
Is there a built-in feature for handling things like:
$$\sum_{i=0}_{i\ne j}^n\frac{a-a_i}{a_i-a_j}$$
and
$$\prod_{i=0}_{i\ne j}^n\frac{a-a_i}{a_i-a_j}$$
or should I work out some sort of Do ...
8
votes
1answer
218 views
Write C/C++ programs calling Mathematica functions
I need to write a C/C++ program and call some functions in Mathematica especially those like Solve or NDSolve. The problem is ...
8
votes
3answers
222 views
Problem when defining variable in Mathematica
I'm trying to run this:
domain := {n, 0, 10};
Plot[n, domain]
but it doesn't work. Instead, it generates the message
...
6
votes
4answers
172 views
Function argument to default under certain condition
Inspired by this and this question (and how I handle this in practice), what is the best way to default a function value when a certain condition is met?
For example, if a function is defined as:
...
5
votes
3answers
161 views
How to rename a built-in function?
I want a built-in function renamed without loss of any properties, I want the shorter name to appear in all results and to be recognized as input. Is it possible?
5
votes
2answers
115 views
A command for outputting a list of parameter values in a Manipulate interface
I am looking for a command that will output a list of values that correspond to the current parameter values manually set on a particular Manipulate interface.
For ...
5
votes
1answer
187 views
Can we know the background code associated with basic mathematica functions
I wanted to know how computers calculate basic functions like Sqrt so first I checked how humans do it I found that they use something called "Newton's method" that ...
4
votes
2answers
183 views
How to make a function that evaluates an expression?
I'm trying to make a function where the input is an expression, but somehow it just won't be evaluated. For example, this little function doesn't work:
...
0
votes
1answer
171 views
How do I numerically solve a custom function?
Whenever I use functions like FindRoot or NDSolve, it sends x through the function and deals ...
9
votes
2answers
119 views
Function with custom Options and modified Options for built-in Symbols
I couldn't find a more descriptive title, but I guess an example will explain my problem.
I set up some customized Grid function including some additional ...
6
votes
2answers
197 views
What's the purpose of the Unique function?
As the title says: What's the purpose of Unique?
I understand that it generates some unique symbol, but when and for what is it to be used? Are there applications ...
5
votes
2answers
592 views
How to create a rectangle wave (duty cycle $\ne$ 50 %)?
I'm trying to use phase-shifted SquareWave[] functions to create a rectangle wave:
...
4
votes
3answers
110 views
How to distribute a generic function of two arguments (without evaluating the arguments)
I guess there is an easy way to do this, but I can't seem to figure it out. What I would like to do is to distribute a generic (i.e. without specifying what this function really does) binary function. ...
4
votes
1answer
202 views
How do I use the result of Solve in a function definition?
I'm trying to adapt the following piece to the part where PowerF is a function of amax.
...
3
votes
3answers
167 views
How to pull scalars out of a function that should act on lists?
Suppose I have
A = a vecA
B = b vecB
where a and b are supposed to be arbitrary scalars ...
3
votes
5answers
257 views
How to use summation to get the value of a binary number?
How to use summation to get the value of a binary number?
I want to do this:
$(x_{n}x_{n-1}...x_{0})=\sum_{i=0}^{n}x_{i}\cdot b^{i} $
But it seems that I can only do something like this:
...
2
votes
3answers
115 views
Alternative to using global variables in functions?
Often times I find myself using unevaluated variables (i.e. they show up blue) as dummy variables in whatever I'm returning such that I can evaluate them as needed later on.
A simple example is as ...
2
votes
5answers
296 views
How to leave function unevaluated programmatically?
Is it possible to write a function in such manner, that it can be either evaluated or left unevaluated?
This is a general question. Sample below is just a sample. No need to find solution for this ...
2
votes
1answer
197 views
Plugging values into functions
I am very new to Mathematica, and need to know how to plug values into existing functions. For example, Math World supplies the following code for building a truth table of ...
2
votes
1answer
331 views
Function output from DSolve
I want to get a function as output form DSolve.
For Example :
sol = DSolve[{Q''[t] + 40 Q'[t] + 625 Q[t] == 100*Cos[10*t], Q[0] == 0, Q'[0] == 0}, Q[t], t]
I ...
2
votes
2answers
267 views
Cannot evaluate differential in Mathematica
I have a small toy script in Mathematica that I am trying to use to evaluate the pdf of $Y$ where $Y=X^2$, and $X$ is uniformly distributed in $[0,a]$.
The script is,
...
1
vote
1answer
168 views
Plotting Fresnel function
I am trying to plot the partial sums and the cesaro means of the function $\sqrt{|x|}$ and for $a_{n}$, I obtained the following code which contains FresnelS.
...
1
vote
2answers
103 views
How can define a set of nested parameters
I would like to know how I to define a function with a nested set of parameters (or whatever you would like to call it). For example, how would I get the following function ...
-1
votes
3answers
198 views
Sqrt — how to get negative branch?
One of the many attractions of Mathematica is that integers are generally treated as exact symbolic entities, and not just as numbers. I was just playing with Sqrt, and was puzzled by what appeared to ...
