For questions on writing functions (pure or using Set/SetDelayed) for any purpose, including the features that may be incorporated in those functions, such as options, patterns and conditions.
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.
...
4
votes
1answer
182 views
4
votes
1answer
162 views
Finding mappings between expressions
Suppose we have an expression of the form:
$j=\frac{A\left(t\right)}{B\left(t\right)}=\frac{C\left(s\right)}{D\left(s\right)}$
That is, $j$ can be expressed either as a function of $t$, or as a ...
4
votes
1answer
166 views
What's the most intelligent way to store the information of a selfmade graph?
I have a very long list of element, say $a1,a2, a3$,..., and they are all connected in that each is the child of many parents. E.g. $a74$ is associated with $a2,a55,a71$, and also contains ...
3
votes
2answers
122 views
How to create 'help' `?` for a function (as documentation)
I have defined a function PassVeltB in some complicated way. But now I would like to add a little documentation that gives the user information on how it is to be ...
3
votes
3answers
166 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
4answers
121 views
Pack Solve results into a vector
I am currently using a really easy function to get the eigenvectors of a corresponding eigenspace:
...
3
votes
4answers
165 views
How to create a composite function from a variable number of components?
Background of the problem: A patient takes a drug every $X$ hours with a half-life of $Y$ hours. How much of the drug will be (exactly) in his system after $h$ hours? For $X=24$, and $Y=24$ I made the ...
3
votes
2answers
182 views
Defining a function using Series? [duplicate]
Possible Duplicate:
General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it?
I need to define a function using the output of series, i.e.
...
3
votes
2answers
79 views
How to define a polynomial/function from an array of coefficients?
I have the coefficients of my desired polynomial in an array CoefArr (I'm new to mathematica, so I think of everything as arrays, it is actually a list I believe) starting with the constant at index ...
3
votes
1answer
150 views
Evaluation of self-defined functions
I defined a function that I call disc which I want to minimize later. The function is defined as
...
3
votes
2answers
206 views
Ways to plot interpolating functions more economically?
I am interpolating a lot of data over geographic coordinates obtained via GPS, and frequently I need to plot these interpolated functions together. For example, I may have an interpolated elevation ...
3
votes
3answers
98 views
How to identify patterns in a tensor-polynomial and replace appropriate symbol?
I want to write a function tensorReplace[input] that takes a tensor polynomial in $r_i$ such as $r_i r_j r_k+r_i q_j q_k +q_i q_j q_k$ , and replaces each monomial ...
3
votes
2answers
109 views
Apply UpValues before Listability
I'm trying to modify Plus but am running into trouble with it being Listable:
...
3
votes
1answer
67 views
Values set using SetOptions are staying in the kernel, beyond the necessary time [closed]
I wrote a function name as functionTest and also mentioned default Options.
...
3
votes
1answer
58 views
User-defined NormFunction in FindFit -
I would like to use a different Norm instead of a p-Norm in FindFit (Mathematica 9). For example, instead of using
Sqrt[Sum[(x_model - x_data)^2]]
I'd like to use
Sum[x_model/x_data].
I can ...
3
votes
1answer
87 views
Is it safe to assign a variable and function of the same name for different things?
I'm writing out a notebook that goes through the van der Waals Equation of State for gases, and I run into a situation where I want to assign (simplified) Tc[b_]:=5b, use that to solve for b in terms ...
3
votes
1answer
107 views
Permuting indices to form fully symmetric tensor with repeated indices
I have written a function (version 8) that takes as an input a list of indices such as {i,j,k} and outputs a fully symmetric tensor function containing $p_i$ and ...
3
votes
1answer
159 views
Stereographic Projection
Say I want to represent points of the complex plane in the sphere $\Bbb S^2$ using stereographic projection. That is, the Riemann sphere:
Specifically, it would be nice to be able to:
Given the ...
3
votes
1answer
78 views
Using NestWhileList to determine smallest prime value in series
I have a function recursively defined as follows:
$a_{n+1}-1=(a_n-1)\times lpf(a_n)$, whe $lpf(x)$ is the least prime factor of $x$.
Now, given an initial value of $a_0$, I would like to find the ...
3
votes
1answer
112 views
Downvalues vs. Scoping for Functions
Regarding my recent question on using a default value for a function argument when a pattern was not met yielded some interesting answers, but the general consensus was "Yes this can be done, but ...
3
votes
1answer
124 views
Feedback on my Subscript code
I have written a code, and I need a little feed back..
I want to make the Subscript distributive across (1) addition and (2) multiplication to mimic short-hand for ...
3
votes
0answers
43 views
How to influence Suggestion Bar in your package/code [duplicate]
Possible Duplicate:
Is it possible to customize the Suggestions Bar?
I have written a little code (like a minipackage) of different functions. In using my code, the user typically starts ...
2
votes
9answers
926 views
How to find palindromic numbers (Project Euler #4)?
I'm trying to solve the fourth Project Euler's problem with this:
...
2
votes
4answers
278 views
How to write a differential operator in Mathematica
I have a very basic question. I am trying to code the LHS of the differential equation:
...
2
votes
2answers
301 views
Creating custom functions with multiple arguments
I am hoping that this isn't a stupid question so feel free to vote it for closure. Google failed somehow.
I want to define a custom function (more complicated than the usual ...
2
votes
2answers
109 views
How to evaluate this product
I was trying to evaluate this product
$$ \sin (1^\circ) \sin (2^\circ) \sin (3^\circ) ... \sin (88^\circ) \sin (89^\circ) \sin (90^\circ) $$
But I think it got weird results with this ...
2
votes
3answers
180 views
How to Compute Aggregate Best and Worst Cases for a Large Number of Estimates?
I need to aggregate multiple estimations, but I haven't been able to find a built-in function in Mathematica that aggregates multiple probablity estimations (I am specially interested in estimations ...
2
votes
3answers
98 views
Map several functions in one routine
I have several functions, let's assume they are:
func1[x_]=x;
func2[x_]=3*x-5;
func3[x_]=0.1*x^2;
and a lot more like these.
For each and every one of these I ...
2
votes
2answers
67 views
Rising Recursion Relationships
Lets say I want to compute the following function in mathematica:
$G[n,k]=G[n+1,k-1] + G[n+2,k-2]$ where I know that $G[n,0]=n$ and $G[n,1]=n^2$.
So, for example, $G[3,2]=G[4,1]+G[5,0]=4^2+5$ or, ...
2
votes
3answers
234 views
How do I construct a pure function to extract data fields from records that are strings?
How can I get from data segment format to the final segment format with a pure function? The data fields are fixed length. There are no separators between the fields.
a) list
...
2
votes
3answers
566 views
2
votes
2answers
102 views
Hiding certain user-defined functions in front-end autocompletion
I have written an elaborate code that contains a collection of functions for the user and a bunch of auxiliary functions whose existence I would like to hide away from the user. I've written my code ...
2
votes
2answers
120 views
Is it possible to use PropertyValue to modify properties of Graph objects in a list?
This post can be seen as a follow up to Property assignment on a graph vertex using PropertyValue does not work inside a function.
I have defined a function:
...
2
votes
2answers
112 views
How to achieve Set+Part like behaviour in custom Set function?
So I've been toiling away on my DataFrame package. I've been trying to get Set to work with it, but it seems it either can't be done (ie via ...
2
votes
2answers
86 views
2
votes
3answers
106 views
Defining a function to determine when convergence is guaranteed
I'm investigating how many iterations are needed for a particular orbit to reach a fixed point of a function. Since I have many functions to test, I want to define a function
in Mathematica that will ...
2
votes
3answers
151 views
Ways to change an explicit function into a pure function
I'm trying to use FixedPoint to solve a transcendental equations, but the first argument of the FixedPoint should be a pure ...
2
votes
1answer
104 views
Can my permutations function be defined using iteration?
I have two functions, tuples and perm. They are similar.
...
2
votes
1answer
113 views
Rookie mistake in defining a function with Modules?
I can't figure out what's wrong with this piece of code. I'm trying to define a function that counts the occurrences of x, y and ...
2
votes
1answer
76 views
Specifying form in MemberQ
This seems like a very simple question, the answer to which should be obvious to me. So I won't be offended if this question is closed. But I'm having trouble figuring out the answer.
I would ...
2
votes
2answers
131 views
Constraining a random function
This question is a follow-up from here. I have a function that generates a list of correlations between some random variables:
...
2
votes
2answers
87 views
Defining a function by pieces using list of interpolated functions in order to use `FindRoot`
I have two lists with the interpolated functions
...
2
votes
3answers
117 views
Function[] argument nesting for operations like Select[]
The following code selects a special element from a list
thelist = {"this", "notthis"};
Select[thelist, (# == "this") &]
What I want is a function which ...
2
votes
2answers
66 views
Putting a matrix inside function
I want to fit a function to some data and inside the function there's a list
here's my data
...
2
votes
1answer
155 views
Why does the first derivative of a piecewise continuous function turns out with discontinuities?
I have this piecewise continuous function which is also continuously differentiable over time :
...
2
votes
2answers
116 views
Working around behaviour of EdgeRenderingFunction
One can make graphs
GraphPlot[{1 -> 2, 2 -> 3, 3 -> 4, 4 -> 5, 5 -> 1, 1 -> 1, 5 -> 5}]
and one can generalize the input such that one ...
2
votes
1answer
87 views
How to override `?NumericQ`
I have a function myFunc which I is to be displayed cleanly if arguments are symbolic, but which can also be numerically evaluated. I do this by defining a ...
2
votes
1answer
84 views
How do I determine if there's an arithmetic sequence within a list? [duplicate]
Possible Duplicate:
find subsequences of constant increase
Given an arbitrarily long list of integers (let's say they are sorted), how would one determine if any 3 (or more) of those ...
2
votes
1answer
112 views
Implementing a For (?) or series or loop (?) for individual results for every x to n
I'm working on improving a modeling formula and have spreadsheets worth of data to use, but my work so far has been quite tedious. I'm essentially pulling 20 rows of data from each separate sheet of a ...
