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

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0
votes
2answers
135 views

How to calculate expected return, row by row in matrix? [closed]

Please help me, I'm writing my project and dont know how to solve this big matrix: I have to compute return row by row: 1st row: (18.32-17.14)/17.14 ; (19.17-18.32)/18.32 .... ...
1
vote
3answers
168 views

Pure function inside another pure function

I have the following working expression: In[15]:= Length[Select[IntegerPartitions[10],First[#1]==5&]] Out[15]= 7 But, instead of using the constant 5 I want ...
6
votes
1answer
247 views

How to type binomial coefficient $\binom{n}{k}$

I know how to type a fraction as you would write a fraction in Mathematica (9). How do you type Binomial[n,k] as $\binom{n}{k}$ in Mathematica? Is there a single ...
6
votes
2answers
112 views

Partial result of aborted evaluation of FullSimplify

When FullSimplify invoked on a large expression, it can run for hours. If I do not have time to wait, and abort the evaluation, I get no result, although, ...
4
votes
3answers
702 views

Make a differentiable smooth sawtooth waveform

So, I am trying to understand the effect of sawtooth waveform on a mechanical system model. For example, a system of a plate and a box on it. And then we try to oscillate the plate. In order to do ...
8
votes
3answers
191 views
6
votes
2answers
178 views

how recover lost data of coordinates from contourplot of mention data?

I have made Contour Plot for a lot of data, like this ...
1
vote
1answer
173 views

Interpolation of a table with 4 parameters

I have a huge data file which I need to do some analysis on it. The file is built in this way that for each 4 variables, there is a value of the function: ...
15
votes
2answers
1k views

Is there an equivalent to MATLAB's linspace? [duplicate]

Does Mathematica have an equivalent to Matlab's linspace? I want to make a list with "start", "stop" and "number of points". What is the neatest way of doing this?
0
votes
2answers
194 views

Using a table to format a grid

Ok, I can't wrap my head around this because I don't know Mathematica well enough yet, so I'm asking for help, at least a direction to explore in. I have a Grid: ...
-1
votes
2answers
217 views

How can I extract when a select condition is met in a do loop the value of the iterator?

I use the following code to find out the number of consecutive prime numbers using a formula $n^2+n+i$ found out by Euler (starting from n=0): ...
0
votes
0answers
97 views

Need Help with Output/Code Optimization Conparative Statics with System of Equations and Matrices

I have a system of equations (equilibrium conditions) and would like to evaluate how changes of exogenous variables affect the endogenous values. In step 1, I state the equilibrium equations and some ...
0
votes
0answers
92 views

Custom Errorbar-Function

I wanted to have a better control on the ErrorListPlot, so I defined a custom ErrorBarFunction: ...
3
votes
3answers
243 views

How would I plot the volume element in cylindrical coordinates?

I have this graph: But it doesn't have a function so I can't just plugin in a function into wolfram or mathematica to plot it. I have these coordinates to make it however: ...
4
votes
1answer
139 views

Volume within parameter space

Imagine a parameter space with variable 0<p<1, 0<e1<1/2 and 0<e2<1/2. ...
4
votes
3answers
212 views

Multiple output cells

Is it possible to have multiple outputs from a single function? For example: In[1]:= x+1 x+2 Out[1]= 1+x Out[2]= 2+x has multiple outputs, how can I ...
4
votes
1answer
149 views

Orthogonalizing without normalizing

Is there a way to make Orthogonalize do the normal Gram-Schmidt procedure without normalizing the result? As far as I've understood this was possible with ...
2
votes
2answers
235 views

How can I iterate my code a 1000 times?

this is my solution to Exercise 5 of http://work.caltech.edu/homework/hw2.pdf Please help me make this more elegant. The exercise is about classifying random Points by a (randomly generated) target ...
5
votes
1answer
65 views

How to bail out from a non-applicable transformation function?

I provide a custom function in TransformationFunctions options of FullSimplify that can do a transformation only for some values ...
5
votes
1answer
197 views

Shortest polygonal path

I'd like to find the shortest distance between some points (every point must be visited), such as between these 3 points: ...
5
votes
0answers
165 views

Strange Integrate behavior (a bug!)

The following two calculations should give the same result. After all, integration is a linear operation. I have pasted the code below in case you want to play with it. ...
0
votes
0answers
54 views

mathematica function autocomplete issue [duplicate]

This is the default function structure prompt from Mathematica 9 This is my own function module ...
3
votes
1answer
308 views

Integral of Lorentzian yields different results depending on when parameter assigments are made

I'm evaluating the integral of a Lorentzian, which I know equals one. First I define the function and evaluate the integral in two slightly different ways. Surprisingly, I do not get the right answer ...
1
vote
0answers
70 views

Decapitating “explicit” and “implicit” heads

This is a follow up to this question. So far, I named "explicit" heads to those that appear explicitly in the expression. For example, f[x] has an explicit head. I ...
7
votes
3answers
439 views

Difference between @ and @@

I am confused by the commands @ and @@. From the documentation, I learnt that @@ is the ...
14
votes
5answers
341 views

Partitioning a list of numbers the Mathematica way

I have two sorted lists, one list will be called the "fences" and the other the "values" Fences could be: $\{1, 5, 9, 14\}$ Values could be $\{-1, 1, 3, 4, 6, 9, 10, 13, 14, 15\}$ I want to ...
2
votes
1answer
82 views

What is the need for function parameters? Many possible inputs

If I have many possible variables related to one another, why do I need to define my function with parameters for plotting? For example, if I have an equation like: ...
1
vote
1answer
162 views

using a Mathematica function to define a new function

I'd like to define a function of three variables which produces a new, named function of a single variable, where this final variable is not a member of the first three. So I'd like something where I ...
4
votes
1answer
229 views

Strange result for the analytic integration leads to Hypergeometric2F1

The integration result for Integrate[1/(r^2 Sqrt[x/r^(4 - 2 \[Gamma]) + 1]), r] is: ...
2
votes
1answer
79 views

Behavior of ValueQ inside a function

The following code Cases[Function[{x}, x + 1], a_?ValueQ :> Hold[a], ∞, Heads -> True] unexpectedly returns {Hold[x + 1]} According to the manual, ...
1
vote
1answer
143 views

How to apply a tensor to a list of arguments

The problem I have is the following: Let C be a list of coordinates, say, C = {x1, x2, ..., xn} and ...
3
votes
1answer
167 views

The UnitStep function and Intervals

For the input UnitStep[Interval[{-4, 5}]] I get Interval[{0, 1}] Why is this not ...
-5
votes
1answer
84 views

Converting function into differential version

I am looking through a journal and I came across a function that I wanted to convert to its differential version using Mathematica. Would anyone be able to get the differential version by using ...
5
votes
1answer
147 views

Reverse engineer a sample value from a CDF

The image below shows the cumulative distribution of a normal distribution with mean = 4 and standard deviation = 1. Notice that if you have a value with a rank of 0.8 (meaning it would be 80th item ...
2
votes
2answers
257 views

Are there Min and Max functions that work properly on Intervals?

Mathematica overloads the Min and Max functions to retrieve the lower and upper bounds of an interval. I need functions that ...
7
votes
1answer
145 views

Understanding FullForm in front end

I want to understand the following effect better (In Mathematica 9) .. Or, maybe, is it a bug? Running the following line FullForm[Subscript[α,β_]] gives as ...
8
votes
1answer
281 views

Two ways of map a function on the list: Which one is faster?

There are 2 ways to make a function listable on the list: Use Map or use SetAttributes. My question is, which one is faster, ...
1
vote
1answer
92 views
0
votes
0answers
74 views

creating some smooth density functions

I would like to create some density functions based on some distance measure $D$. As a base density function lets say I have a Gaussian density $f$ with mean $-1$ and variance $1$. I would like to ...
6
votes
1answer
190 views

Iteration process involving several functions

I would like to carry out a following iteration process: Apply function f1[a_,b_,c_,d_] to a starting list l1={a1,b1,c1,d1}, ...
5
votes
1answer
108 views

Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
2
votes
1answer
109 views

Function to differentiate between date pattern and specific string format

I'd like to write a function that behaves one way when the argument is a Mathematica date, such as {2013,12,15}, or with added hours, minutes and seconds if ...
0
votes
2answers
80 views

I want to define a function that has integer power [closed]

I am defining this function: f[x_] = kr*g[x] + (c^l*x^l)/(KIR + c^l*x^l) But I want to make l bigger than 0, so if I evaluate ...
3
votes
2answers
208 views

Selecting for 2D points that are within a threshold distance of an upper- and lower-bound number of points

I have a very large set of 2D points: numberOf2DPoints = 10^6; pointList = RandomReal[{0, 1000}, {numberOf2DPoints, 2}]; I'd like to find a way to quickly ...
1
vote
1answer
134 views

Passing a joined list of symbols for Module or Block to treat as its own local symbols

The Question I'd like to write a function which itself takes a list of symbols, e.g. Foo[{x, y, z}] to pass to Module ...
5
votes
1answer
293 views

How to express an expression with only ArcTan and ArcTanh?

I have an expression which is simply (j/k) x^(j/k) LerchPhi[x,1,j/k)] where 0 < j < k. Manually I have been able ...
6
votes
1answer
154 views

The third argument of the Root function

Consider the roots of an arbitrary indecomposable polynomial: sol = Solve[x^5 + 2 x + 1 == 0, x] The returned expression is ...
0
votes
1answer
88 views

Is there any automatic method for rating function arguments importance?

If I have a function: y = 2a + 5b + c It can be easily seen that b is the most important parameter, next ...
0
votes
1answer
62 views

Stop function evaluating input at time of definition [duplicate]

I would like to create a function that acts on whether the input is even or odd, e.g.: In[644]:= f[a_] = If[EvenQ[a], 2 a, 3 a]; f[2] Out[645]= 6 I've ...
2
votes
2answers
161 views

Generation function of recurrence sequence

I'm trying to find generation function of recurrence sequence ...