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

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0
votes
1answer
17 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 ...
0
votes
1answer
25 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 ...
2
votes
2answers
110 views

Permanently rounding numbers/values to a given number of significant figures

I am searching for a simple way of rounding and setting an input to a desired number of significant figures. There are a vast number of posts that discuss similar problems, but none address this ...
2
votes
1answer
79 views

PrimitiveRoot function

The function PrimitiveRoot[n] claims to return the smallest primitive root of n. I believe this is not true. For example ...
28
votes
2answers
800 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 ...
4
votes
2answers
82 views

DeleteMissing issues [duplicate]

Has anyone had problems with the DeleteMissing function in Mathematica 10.0.2? I find that it rarely works. Most of the time it returns a list which still contains ...
1
vote
2answers
38 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, ...
0
votes
0answers
88 views

Problem with FindRoot applied to functions

I am having difficulty with the error "is not a list of numbers with dimensions..." when using FindRoot (and other numerical routines in Mathematica) to solve equations numerically when the argument ...
-4
votes
0answers
46 views

How to write the following subroutine in Mathematica and then how to call it? [on hold]

This is the routine wriiten in fortran i want to apply in mathematica as a subroutine and then want to call it where needed. I tried this one ...
2
votes
4answers
183 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
votes
1answer
61 views

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

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
41 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
81 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 ...
10
votes
2answers
876 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
70 views

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

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. ...
7
votes
1answer
112 views

Compability between Graphics coordinates and shifted projections in GeoGraphics

I'd expect GeoGraphics to handle positions of points since they are provided with GeoPosition wrapper. But it is not the case ...
1
vote
1answer
38 views

LineScaledCoordinate problem for exact coordinates

Edit: Confirmed bug. CASE:2326540. Solution: Wait and use N meanwhile. I've faced this problem writing an answer for ...
0
votes
0answers
45 views

Applying the square root of operator on polynomial functions

I am trying to apply an "operation" on polynomial functions: apply the operator $(\frac{\partial f}{\partial x}-y\frac{\partial f}{\partial z})^2+(\frac{\partial f}{\partial y}+x\frac{\partial ...
1
vote
0answers
52 views

What's real analogue for FromDigits?

FromDigits only works for integer strings. What's its real-number analogue?
2
votes
2answers
118 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
92 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
38 views

ParametricPlot3D plot n functions [closed]

Below is the code I am aiming to get, however I do not know how to have mathematica dynamically generate code to create n numbers of {..., examplefxn[[n]], ...}, ...
0
votes
0answers
70 views

Numerical Integration/Function

I have a problem with a function defined numerically through an integral of the form: ...
2
votes
1answer
72 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
35 views

Defining Solutions to FindRoot a functions of parameters-Part II

Here's a similar question as the the preceding question with the same title, but this time with vectors, which I need to use. I followed the suggestion in the answer the the previous question, but it ...
0
votes
1answer
51 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 ...
7
votes
2answers
202 views
3
votes
0answers
49 views

Using an external Pattern breaks Format

I noted while writing this answer that using an external Pattern on Format doesn't work: ...
4
votes
1answer
81 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
135 views

Loop function question [duplicate]

I'm new to Mathematica. Below is the code I have trouble with. ...
4
votes
3answers
135 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 ...
0
votes
1answer
69 views

How to fill a Marshal buffer with whitespace using NETLink

Further to Todd Gayley's answer on string handling in a DLL function, I have the following code: ...
1
vote
3answers
86 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 ...
0
votes
0answers
97 views

How to speed up my code with constructing matrices

I have run this program for a long time to get the result for n = 2048(about 5hours) and no more result till now (can't run with n = 4096). I would know how to make it more efficient. Any help or ...
3
votes
0answers
65 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 ...
0
votes
2answers
58 views

Operations on transfer function model

Suppose I have a transfer function defined via TransferFunctionModel, e.g. tf == TransferFunctionModel[{{1/s}}, s]. How can I ...
8
votes
0answers
95 views

Why is this evaluation halved when adding units?

Why does this strange behavior occur when dealing with units and quantities? ...
1
vote
0answers
57 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 ...
1
vote
1answer
101 views

Manipulate - Evaluating Value of Function

I would like to visualize the properties of a threshold, which is a value of a function. Unfortunately, the value is expressed as scientific value (an approximation with 3-5 decimals would be fine) ...
0
votes
2answers
75 views

Choosing pairs from a list that satisfy a certain equality [closed]

If I have many numbers in here {{A,B},{C,D},{E,F}.....} And I want choose the B,D,F,....(the second number) to run a function y=f(x), where x=B,D,F.... Then I need to check if y=f(B) is equal to A or ...
3
votes
1answer
87 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
73 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
35 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
103 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
42 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?
2
votes
1answer
85 views

IntegerQ and Element Integers give different results in one case

f1[x_] := IntegerQ[x] f2[x_] := Element[x, Integers] Both functions give identical results in everything except for such case: ...
0
votes
2answers
50 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
68 views

FullForm applied to functions

I would have expected FullForm[Cases[{a^2, a^3}, a_^1]] to produce ...
0
votes
0answers
65 views

DeleteDuplicatesBy function does not exist

I'm using 10.0.1.0 x64 on Windows. The DeleteDuplicatesBy function appears in autocomplete lists, and is present in the documentation, but does not appear to ...