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

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1
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1answer
58 views

Function does not initialise variable as changes are made in the manipulate function

My function "DefineRss[]" takes in three arguments and outputs a plane value. It sits in the first argument of the function plot3D and that in turn sits in the manipulate function The function also ...
1
vote
1answer
220 views

Shorthand for operations?

Mathematica has a large number of built-in symbols, and I am unsure when there is a shorthand for the operation I am trying to perform. Question 1: Is there a shorthand for the function ...
2
votes
0answers
25 views

Determining default value from previous arguments [duplicate]

How does one specify a default value for an argument which is dependent on the previous arguments of a function? For instance, consider the function ...
5
votes
5answers
413 views

What is primary, function computation or function application?

What is the order of computations here? g[x_]:=x^2; f[x_]:=Sqrt[g[x]]; Map[f, Range[100]] Does this code first get $f(x)=x$ and then gives its values or for ...
1
vote
1answer
141 views

Minimize under constraint on an interval

I want find the minima of a (multivariable) function under a constraint which has to be fulfilled on a whole interval, let's say $$ \nabla f (\underline x) = 0 \ \\ \ c(\underline x,s)\geq0\ \forall s\...
2
votes
1answer
109 views

PrimitiveRoot function

The function PrimitiveRoot[n] claims to return the smallest primitive root of n. I believe this is not true. For example ...
32
votes
2answers
944 views

Is there a name for #1@#2&?

Why does the pure function # @ #2 & have no name? I'm asking because sometimes I find inelegant to write expressions like ...
1
vote
2answers
169 views

Evaluate list of functions at a certain point

I have a list of functions (actually they are derivatives) of the type: {D[g[x,y],x],D[g[x,y],y]} I would like to evaluate all of these functions at a point, say,...
-1
votes
1answer
80 views

My code of plotting a two-variable function is too slow [closed]

I have a code in which my complicated function to be plotted is F(x,p). I would like to graph it for 5 values of p equal to 10^7, 10^8, 10^9, 10^10 and 10^11 for x values between 0.01 and 0.99. All ...
0
votes
1answer
149 views

How can I change variable passed to a function? [duplicate]

Sometimes I'd like to make a function, which would take an argument "by reference" instead of usual "by value". This is semantically similar to what e.g. AppendTo ...
3
votes
1answer
121 views

RegionPlot fails when given function with internally redefined variables

I've just upgraded to v10, and have noticed that some of my trusty old notebooks which used RegionPlot now fail to run. I've boiled down the problem I'm having to ...
16
votes
2answers
2k views

Determine whether some expression contains a given symbol

Given a symbol t and an expression expr, how can I determine whether or not the symbol t ...
0
votes
1answer
116 views

Finding x when sin(x) = -.758 [closed]

I'm not understanding how to find all the angles for when sin(x) is equated to a negative decimal can someone explain to me how to find it..? So far I came up with 49.288 degrees, and 229.288 degree. ...
2
votes
2answers
278 views

Polynomial expansion of operator

I am new to Mathematica, I am trying to generate the polynomial function of a operator. So for example, the operator $L $ is $\frac{\partial f}{\partial x}+\frac{\partial f}{\partial y} $, and I want ...
4
votes
1answer
143 views

Display level of recursion of a recursive function during execution

Given a recursive function, is there some simple way to display or store the value of recursion or "how many levels deep" the function is at a given time? For instance, if we wrote the recursive ...
0
votes
0answers
93 views

Numerical Integration/Function

I have a problem with a function defined numerically through an integral of the form: ...
2
votes
1answer
123 views

How-to convert real number into List of its digits?

How could I convert a real number into a List of its digits in Mathematica? Example: 8.168643234 Desired output: {8,1,6,8,6,4,3,2,3,4} Many thanks in ...
0
votes
1answer
150 views

Recursive definition of nested sums

I have a set of functions which take lists as arguments. They recursively nest sums, and I have defined them as follows ...
8
votes
1answer
376 views

Is there a built-in function to do binary search?

Is there a built-in function to do binary search? Say, given a list (sorted) and a number, find the position which keeps the listed sorted when the number is inserted. I know that ...
0
votes
1answer
161 views

Loop function question [duplicate]

I'm new to Mathematica. Below is the code I have trouble with. ...
4
votes
3answers
160 views

Getting terms and only evaluate specific parts

I want to expand the expression but I do not want it to evaluate. Sum[(HoldForm[1/(2 # - 1) - 1/(2 # + 1)] &)[i], {i, 1, 6}] However if you evaluate this you ...
1
vote
3answers
216 views

Breaking a While loop

A simple example to illustrate what I'm talking about: m=0; While[m<=50, m=m+1; p=m] The result is: m=51 p=51 In ...
3
votes
0answers
176 views

Extracting an equation from an interpolated function

Im trying to use LibraryLink to do some calculations in C but part of the expression i want to calculate is an Interpolating Function. C cant use that obviously so I'm trying to shift it to a data ...
1
vote
0answers
60 views

How to put Black as the background colour, and text as white in Mathematica? [duplicate]

My question is equal to this one,even though by different reasons. I would like to know how can I change the white background to black, and the black text to white. I'm asking again, since a year has ...
3
votes
1answer
98 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.
0
votes
2answers
96 views

Parametric Function

i'm struggling to implement the following parametric function: I need to create a g function with two arguments (w and v). If w and v are not empty lists, then it will return a list containing two ...
1
vote
0answers
58 views

Input `Reduce[Mod[a + x, l] == 0, x]' and output `x == -a + kl`?

Reduce[a + x == k l && k > 0, x] (* k > 0 && x == -a + k l *) I think a + x == k l and ...
5
votes
2answers
137 views

How to use Manipulate to cycle through a list of lists over a function

So I can do something like this which I like: Manipulate[i, {i, {1,2,3,4}}] It lets me pick which specific values I want to allow to be chosen for my function. ...
3
votes
0answers
95 views

How to add my own functions to the library? [duplicate]

I would like to have my own functions (some sort of helper or utility functions) available all the times I run Mathematica. How to do that?
0
votes
2answers
84 views

Solving coefficients of a function having boundary conditions

I have a function F=c+dz, which has particular boundary values, say F(z=1)=2 and F(z=-1)=1, ...
2
votes
2answers
130 views

FullForm applied to functions

I would have expected FullForm[Cases[{a^2, a^3}, a_^1]] to produce Cases[List[Power[a, 2], Power[a ,3]], Pattern[a, Blank[]]]...
1
vote
1answer
136 views

Write 7. as 7.0 and .7 as 0.7 [closed]

i would like to know how to do in order to transform using a function .7 in 0.7 and 7 in 7.0. I need that the values in the list will really change because i must print them in a text file. Thank you....
10
votes
1answer
283 views

Max element of a list with a custom ordering function

I need a function to find max element of a list according to some custom ordering function, assuming that the function implements a total order (elements being compared might not even be numbers). ...
12
votes
8answers
608 views

Find the minimum integer r such that $(10^r - 1)/37$ is an integer

I know Element[(10^r - 1)/37, Integers] tests the condition. So what is the command that gives me the minimum integer value r ...
1
vote
2answers
163 views

Pattern Match and Replace Expression involving Pure Function

Let's say I have an expression that in held form contains a pointer to a function. expr = Hold[2*{"FUNCTION1"} + 5]; ...
2
votes
1answer
45 views

Default value behaves differently when used in Function and when used with Cases

Consider this example: Cases[{4, x, 5 a , 6 x}, x_.*a_ :> x] (*{1, 1, 5, 6}*) It is clear that the _. took 1 as a ...
2
votes
2answers
168 views

Generating a permutation of elements in chunks

Is there a way for me to generate a list of permutations in "chunks" such that I needn't store everything on RAM all at once? Consider that (WARNING: DO NOT RUN! --- Will generate a list with 13! = ...
2
votes
1answer
61 views

Double application of NIntegrate produces unexpected error messages [duplicate]

In the course of trying to answer 69601, I encountered unexpected error messages. In highly simplified form, NIntegrate[NIntegrate[z y, {y, 0, 10}], {z, 0, 10}] ...
13
votes
11answers
1k views

Divide all but the maximal element in a list by 10?

I have a list of numerical data, and I want to write a program that will keep the maximum as it is, but reduce the rest by certain factor (such as 10). For example: ...
1
vote
1answer
1k views

Computing the fundamental matrix and its monodromy matrix

Assume $\dot x(t)=v(x,t)$ is a $T$-periodic, with respect to $t$ dynamical system. That is: $x\in\mathbb R^n,\quad t\in\mathbb R,\qquad v(x,t+T)=v(x,t)$. Let $x_0$ be a smooth periodic solution in ...
4
votes
1answer
182 views

Coefficients of a polynomial in powers of 10

Can I express a polynomial function in Mathematica in power (ScientificForm) ? I was trying: ...
1
vote
0answers
80 views
0
votes
2answers
479 views

Replace variables and redefine a function

I would like to redefine a function f(x)=1+2x^2 to a new function g(y)=1+2y by using the replacement ...
1
vote
2answers
174 views

Josephus problem

See the Josephus Problem. My code takes in two numbers; one is the number of participants, and the other is supposed to be the number of players skipped between executions. ...
2
votes
2answers
71 views

Incomplete Integration in Area

Area[2 Sqrt[(1 - p^2)^2 - r^2], {p, 0, 1}, {r, 0, 1 - p^2}] is able to perform only the integral over r, leaving the integral ...
1
vote
1answer
81 views

Aborting from a Dialog box

I'm trying to abort a While cycle, with a dialog box. I've tried the following: ...