Questions about the use of built-in Mathematica functions, including pure functions.

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10
votes
1answer
336 views

Why does the documentation call functions “pure”?

Clearly, functions in mathematica are not pure functions according to the definition on Wikipedia (no side effects - basically implementabe with table lookups): ...
1
vote
1answer
307 views

How can I call the R-programming packages in my Mathematica?

I am trying to call the R-programming package called highfrequency in my Mathematica so that I can use its function rCov. I ...
1
vote
1answer
139 views

handling division by zeros and line equations

today I was writing a code which takes some line equation and a circle equation,finds intersection points that are on $II$ and $III$ quadrants,draw a tangent line to circle from that point and then ...
1
vote
1answer
58 views

Multiway Systems Rules List Management

I'm working with a multiway system and I have a number of different mutation rule lists. I need an efficient way of managing which rule lists I apply. Here is the basic multiway system code that I'm ...
1
vote
1answer
102 views

Plotting a function in {X(Y),Y} space

The code below generates some data and defines a function f[x,cb]:=NMaximize[expr,x] that upon being evaluated returns: {function value at max $x$,the function maximizing $x$}. ...
7
votes
2answers
207 views

How to redefine the type of multiplication in Det

I would like to redefine the type of multiplication that is used in Det (calculates the determinant). Instead of the standard multiplication I would like to use a custom function Fun[a,b] (which takes ...
14
votes
1answer
272 views

Why do big-O terms disappear in definite integrals since Mathematica 9?

In Mathematica 8, when I computed the following input: Integrate[Series[Cos[x], {x, 0, 2}], {x, 0, a}] Mathematica returned an expression that had a O[a^4] in ...
3
votes
1answer
96 views

FinancialDerivative function call without parameter fails in Mathematica 10

fixed in 10.0.2 When I type FinancialDerivative[] in Mathematica 10. There is error listed as follows. Anybody know how to solve it? Thanks.
1
vote
1answer
84 views

User defined functions and decimal places displayed

I have a couple of complicated user-defined functions, one which calls the other, and I wish to control the number of decimal places displayed when I call the "mother" function. I have tried the ...
1
vote
1answer
79 views

In which version was this Extract syntax introduced?

In Mathematica 10.0.1 this works: Extract[{a, b, c, d, e}, {{{1, 3}}, {{5, 4}}, {{2}}}] {{a, c}, {e, d}, {b}} In ...
3
votes
1answer
58 views

Automatically discover the class of an arbitrary matrix

In Wolfram|Alpha it is possible to discover some specific classes to which a matrix belongs. For instance, typing this in Wolfram|Alpha ...
3
votes
0answers
248 views

Distance Time Warp (DTW) function implementation in mathematica

The DTW (Distance time warp) is given here http://en.wikipedia.org/wiki/Dynamic_time_warping There is an implementation of DTW in R as well as MATLAB. However i am unable to find something for DTW in ...
2
votes
2answers
186 views

Returning the 3-dimensional vector from a skew symmetric matrix

I'm trying to write a function that takes in a skew symmetric matrix and returns the corresponding vector. When I write the following code, it works when I leave it as variables, but it does not work ...
4
votes
2answers
149 views

Can't figure out how to apply these functions repeatedly

I have the following problem, and even though I've tried Fold & Inner, Sow & Reap, et al. I can't figure out the clean way to do this. Here's the problem. I have a list that starts as ...
1
vote
1answer
220 views

C compiler error: the no library could be generated error

I have windows 8, Mathematica 9, and I've just installed Microsoft Visual Studio 2013 with update 3. I'm try to run Compile with the option ...
7
votes
2answers
594 views

How to create a function like in Python

I want to call a function that would perform a function rather than assigning an expression to them. I.e. ...
7
votes
2answers
291 views

Why doesn't this pattern work?

I want the in-built function Count to count the elements in a list which are greater than a value. Example: ...
0
votes
2answers
73 views

How do I get a Do function to create a list?

I have a Do function which gives me a column of expressions. How can I get the Do function to give me these expressions in a list. i.e The do function gives me this: a b c d I would like it do give ...
0
votes
2answers
2k views

Problem in downloading “ToMatLab” package [duplicate]

Iam trying to download "ToMatLab" Package from http://library.wolfram.com/infocenter/MathSource/577/ but it is showing me an error message by showing a big question mark and "File could not be ...
0
votes
1answer
97 views

Functions in functions

I have three functions f(x,y) , g(t) , and h(t) and somehow I have to find (d/dt)f(g(t),h(t)) where t = 0. How would I go about writing this in Mathematica? In this equation g(t) is taking place of x ...
6
votes
1answer
140 views

Unexpected behavior from Indexed (threading and messages)

I was going to include Indexed in this answer, thinking that it operated much as a List-only ...
2
votes
3answers
362 views

Extracting coefficients from a power series

I have a function defined explicitly as a power series: $$\sum_{n=0}^\infty{T_n}\frac{x^n}{n!}=\frac{\frac{x^3}{3!}}{e^x-1-x-\frac{x^2}{2!}}$$ and I would like to extract the coefficients $T_k$ as ...
15
votes
6answers
784 views

How can I evaluate only a single step of a recursive function?

Let's say have a simple recursive function for the Fibonacci sequence f[0] := 1 f[1] := 1 f[n_] := f[n - 1] + f[n - 2] but I want to see how it will expand in a ...
3
votes
2answers
88 views

Conditional replace of a column

Im trying to replace the value in the Nth column of a list if a condition is true, returning the modified list. I've tried modifying the answer from 61219 and been through most of related questions ...
11
votes
3answers
245 views

How to deal with the condition $u_i=u_{i+1}$ in B-Spline basis function?

The defintion of B-Spline basis function as shown below: Let $\vec{U}=\{u_0,u_1,\ldots,u_m\}$ a nondecreasing sequence of real numbers,i.e, $u_i\leq u_{i+1}\quad i=0,1,2\ldots m-1$ $$N_{i,0}(u)= ...
0
votes
1answer
37 views

Rigging a function to output a distinct value every nth call

There's some fixed script I am unable to alter (keeping things simple: Table[f[i], {i, 1, 10}]), , however, I can alter a function that the script calls (again, ...
0
votes
1answer
42 views

Trouble definining a function to use only certain heads

I'm trying to write a function that accepts only a particular Head (for example, prints only Symbols) using pattern matching. However, the following code has me a bit of confused. ...
4
votes
4answers
120 views

CoefficientRules for negative powers

CoefficientRules acts like the following. ...
4
votes
1answer
302 views

Mathematica doesn't simplify a simple expression

The question is simple as that. I have: ...
0
votes
0answers
42 views

How can I mix // with a function of two arguments? [duplicate]

I often find myself using // when playing around with expressions, but it is always cumbersome to have to switch to the full notation just to apply a function of ...
1
vote
0answers
33 views

Analog of GeneratingFunction for Newton series [duplicate]

GeneratingFunction gives the generating function for Maclauren series. I wonder if there a similar function for Newton series. If $$g(x)=\sum_{k=0}^{\infty}\frac{x^k}{k!}f(k)$$ Then g(x) is ...
1
vote
2answers
92 views

How to define a function that counts the exponents

I want to define a function $F$ described as follows: The input of $F$ is a polynomial such as m*u*x^4*y + n*v*x^2*y^3 where $m$ and $n$ are constants, and ...
0
votes
2answers
183 views

Time value of Money Functions combined

I am trying to combine multiple functions into one. I have defined following functions: (PV refers to Present value, FV refers to Future value, i or IPER refers to interest per period, pmt refers to ...
8
votes
2answers
210 views

Is there a way to revert to the built-in function after overwritting it using Unprotect

When using Unprotect, we can overwrite a functions definition: Unprotect[Sqrt] Sqrt[x_]="blahblah" Protect[Sqrt] Once this is done, can we revert to the built-in ...
23
votes
3answers
1k views

Visualisation of a recursive function

Is there a way to nicely visualize recursive functions? (diagrams/plots) More specifically I'm looking for a way to make contrast (visually) between e.g. the cosine function which if continuously ...
5
votes
5answers
266 views

Replacing columns of a matrix with zeros

I am to create a function that replaces columns 'm' through till 'n' with zeros. Here is what I have so far: ...
3
votes
1answer
153 views

How do I format Compile[] correctly?

My Mathematica skill is still rusty, so kindly bear with me. I'm having problem formatting expression to compile the function correctly: $\sum _{g=1}^G \sum ...
2
votes
1answer
397 views

Smoothing a single rectangular pulse in NDSolve

Hello I am interested in smoothing out the sharp edges of a single rectangular wave centered at the origin. I am looking for a smooth function that looks almost exactly the same as the square wave ...
14
votes
3answers
2k views

Fitting ellipse to 5 given points on the plane

Five points are required to define a unique ellipse. An ellipse has five degrees of freedom: the $x$ and $y$ coordinates of each focus, and the sum of the distance from each focus to a point on the ...
2
votes
3answers
158 views

Function to Expand exponentials

Is there a function similar to PowerExpand which expand exponentials? This would, for example, take Exp[5(a + b)] and ...
7
votes
2answers
529 views

Modifying parameters: Set::setps in the part assignment is not a symbol [duplicate]

Ok, this will probably be a silly question, but I can't get my head around it. I'm making a simple module that, given a list and two integers, will swap the position of the elements in the ...
3
votes
1answer
104 views

JordanDecomposition in Mathematica

I'm trying to find the Jordan Decomposition in Mathematica for $$ A=\left( \begin{matrix} 2& -5& 8&-12\\ 1& -2& 4&-8\\ 0&0&2&-5\\ 0&0&1&-2 \end{matrix} ...
6
votes
5answers
2k views

Find function inverse

I'm trying to find the inverse of a function: (30*x^2 (1 - x)^2) (* where 0<x<1 *) I tried all the following options: 1. ...
2
votes
2answers
344 views

How to explain NDSolve that functions must be positive only?

I have a simple system of differential equations to solve but both functions should be positive: x[t] > 0 and y[t] > 0 for all t. I was not able to explain NDSolve this fact so it goes x[t] < 0 ...
3
votes
1answer
121 views

Ted's explanation for the 3rd argument of ListCorrelate doesn't apply to the {1, -1} case?

I was reading Ted Ersek's explanation for the usage of ListCorrelate(.nb version can be found here) and noticed something confusing. It's the third example of ...
14
votes
2answers
981 views

Extracting the function from InterpolatingFunction object

I've used Interpolation[] to generate an InterpolatingFunction object from a list of integers. ...
2
votes
0answers
106 views

Incorrect output from InverseFourierTransform

Bug introduced in 8.0.4 or earlier and fixed in 9.0.1 or earlier I am trying to compute the inverse Fourier transform of this expression ...
1
vote
3answers
221 views

Can I find constants in a function?

Let's say, I have a function with a constant, e.g. $y(x)=x+c$, and a condition $y(0) = 5$. I want to type in something like Solve[{y[x]=x+c, y[0] =5}, {c}] and get ...
3
votes
1answer
216 views

StreamPlot in Mathematica

A $2\times 2$ linear ODE system can be visualized by StreamPlot in Mathematica. For example: ...
4
votes
0answers
237 views

Strange behaviour of MMA in derivatives of some standard functions

There are some peculiar things to be discovered in derivatives of some standard functions in MMA: Strange behaviour Example 1: Abs We have ...