Questions tagged [expression-construction]
The expression-construction tag has no usage guidance.
0
votes
1answer
25 views
Displaying positions in expression tree
Can one display the position of each character in an expression tree? For instance: g[h[i, h], l] should be displayed using TreeForm where each character is ...
0
votes
1answer
72 views
How to pass an expression as list elements for a Mathematica command
I'm trying to build a generic function that will calculate sums on different iterators.
To simplify let consider:
...
0
votes
0answers
11 views
Transform String to Expression [duplicate]
I have a variable postVector and another called CHKpostVector. Both are global variables.
Only the variable ...
2
votes
3answers
610 views
How to define constants in Mathematica like c1,c2,c3,…cn?
Manually defining the constants is tedious if the 'n' is large. how to do this?
3
votes
1answer
46 views
Generate multivariate monomials with constraints
I'm trying to generate multivariate monomials in variables $p_1, \ldots, p_n$. Each monomial has either $p_i$ as a factor, otherwise $(1-p_i)$. I need to generate all monomials which have exactly $k$ ...
3
votes
1answer
70 views
Creat a matrix with boundary condition
I would creat a symmetric matrix, but how can I set the boundary in Subscript?
...
7
votes
2answers
148 views
Constructing expressions using Sum vs Array[… Plus] vs Plus@@Table[…]
For constructing a sum of terms which are symbolic, I noticed that in addition to
...
-5
votes
1answer
62 views
Translation of GLSL expression (2) [closed]
What's the most compact WL translation of this GLSL expression:
length(max(vec2(x,y),s))
?
0
votes
0answers
50 views
Generate a system of linear differential equations from a coefficient matrix
I want to generate a system of linear equations that is stable. For that I generated random coefficients and divided the 10 by 10 matrix by the largest eigenvalue and set the diagonal to -1:
...
19
votes
4answers
920 views
Is expression in Mathematica well defined?
According to Mathematica, everything is an expression. So an atom is also an expression. But in other parts of documentation, they say that an expression is of form ...
1
vote
0answers
53 views
How to send Map[Plus[1, #] &, {1, 2, 3}] to Mathematica from C# via IKernelLink?
Here is a piece of my code
...
4
votes
4answers
533 views
Replace element of a matrix with condition
consider a matrix
$\left( \begin{array}{ccccc} 0 & 0 & 1 \\ 1 & 0 & 0 \\ 1 & 1 & 0
\\ \end{array}\right)$
How do I do a program that does these steps
1-Replace each ...
4
votes
4answers
273 views
Generating a family of 0-1 matrices satisfying a particular property
I'm looking for an elegant way to generate the set of all possible matrices that satisfy the following properties:
Each matrix has 9 rows and c columns, where 1<=c<=9.
Each matrix has exactly ...
9
votes
3answers
160 views
Graph that shows how symbols are used in an expression
I would like to make a graph to show how symbols build up an expression. For example, the matrix multiplication
$$
\left(
\begin{array}{ccc}
a & b & c \\
d & e & f \\
\end{array}
\...
-1
votes
1answer
50 views
Producing the same output as Tuples[{0, 1}, 4]? [closed]
How can I use the functions decimalToBinary and padWithZeros to produce the same output as ...
4
votes
3answers
242 views
Handling multi-part equations
How are multi-part equations best handled? For example, take the torsion equation:
We could express part of this equation like this:
...
1
vote
2answers
76 views
How to generate expression a + a1 e1 + a2 e2 + a12 e12 (subscripted)?
Sorry to ask this twice. I thought I could get away with just a0 + a1 e1 + a2 e2 + a3 e1 e2, but for my application I can't. I can generate a + a{1} e1 + a{2} e2 + a{12} e12 (subscripted), but that's ...
5
votes
3answers
133 views
How to make RawBoxes to be Expression
expr = First@
Level[Values@
WolframLanguageData["Plot",
EntityProperty["WolframLanguageSymbol",
"DocumentationExampleInputs"]], {3}]
Plot[Sin[...
1
vote
4answers
225 views
How can a generate an expression like a0 + a1 e1 + a2 e2 +a3 e3 + a4 e1 e2 + a5 e1 e3 + a6 e2 e3?
I wish to input n and then generate an expression. It would look like the above when $n = 3$. I would like to use subscripts for ...
4
votes
3answers
210 views
a function to extract all subexpressions from an expression
Can somebody help me with a function f such that it extract all sub expressions (i.e. looking down the expression tree) from any expression given to it and also a ...
0
votes
1answer
76 views
1
vote
0answers
56 views
How Defer[1+Evaluate[1+1] work?
I want to generate some expressions.
The expression is not evaluated expect some parts will evaluate first.
A simple example is
Defer[1+1+1] and in this expression ...
0
votes
1answer
57 views
1
vote
1answer
184 views
How to overload the operator “*” as KroneckerProduct [closed]
Can I use the expression below
a * b * c * d
for short to instead
KroneckerProduct[a,b,c,d]
automatically when a,b,c,d are ...
0
votes
1answer
81 views
Solving equations with change of variables is not working?
I want to express it in the form
$$\text{expr=}\int_{-\infty}^{\infty}C_1\exp\left(-t^2\right)f(t)dt$$, i.e., the integrand is a bounded smooth function $f(t)$ times $\exp(-t^2)$ and the domain of ...
6
votes
3answers
488 views
How to convert a string into a structured list
I am trying to use an efficient notation for the timing of sounds that i can play in Mathematica.
I would like to parse the string
"{ab{c{de}}f}"
as the list ...
0
votes
1answer
54 views
Is it the correct syntax with TransformedDistribution?
I define a function as f[x_] := ...;which is in fact the PDF of a random variable $X$. The PDF if given by $f_X(x)$.
Let $Y$ is a random variable, which is the ...
1
vote
2answers
312 views
How to find the lowest power in multi-variable expression?
I am sorry for asking a similar question again. I asked How to find the lowest power of variable in expression? and I got a wonderful answer, but I have one more question for a multi-variable ...
2
votes
2answers
496 views
How to find the lowest power of variable in expression?
If I have expression like
a1/x +a2/x^2 + a3/x^3
I want to return 1/x^3. In general case,
...
3
votes
2answers
94 views
Find most general 3-tensor under given constraint?
Consider A to be a general $2\times 2\times 2$ tensor:
A = Table[ a[i,j,k], {i, 1, 2}, {j, 1, 2}, {k, 1, 2}];
pictorially one ...
5
votes
1answer
247 views
How to represent 1 as Symbol[“Integer”]
Maybe this is a boring question, but I cannot figure it out. Because every expression has a Head, and Head[1] is ...
0
votes
1answer
453 views
Convert string to function with an argument
I am trying to build an expression by first writing it out as a string and then using ToExpression to convert it to an expression. However, I cannot figure out how to make expression recognize x as an ...
7
votes
5answers
939 views
Create a list of all possible multivariate monomials of a certain order
Given variables x[i] for i=1,2,...,n I would like to create a list of all possible multivariate monomials of order ...
0
votes
0answers
59 views
What is the meaning of #, Root and & [duplicate]
I am new, but can any one tell me what is the meaning of formulas of x and y in the picture?
2
votes
3answers
92 views
Specify number of elements instead of step in Table [duplicate]
I think I have seen what I was looking for a ong time ago but I can't see nothing such in documentation.
Quite often, I would like to create a Table with given ...
1
vote
1answer
85 views
How to obtain differential consequences of linear transport equation automatically?
Motivation
Here I've asked how to derive coefficients of numerical approximation of the linear transport equation
$$
u_t + u_x = 0,
\tag{1}
$$
on a fixed 3-point stencil automatically and here I've ...
0
votes
1answer
61 views
Misunderstanding of Replace code
I am looking for the right way to replace $\delta \, \, \text{by} \, \, 0.05 \, \, \, \beta \, \, \, \text{by} \, \, \, 1.77 \, \, \, \text{and} \, \, \, n \, \, \, \text{by} \, \, \, 12$ in this ...
0
votes
1answer
111 views
I have a term 'Keff' in terms of 'W'. I need to write 'W' in terms of 'Keff'. Does Mathematica provide an option for that
I have read similar answers on this topic. I am still not able to execute my code.The code is as follows.
...
0
votes
1answer
64 views
0
votes
1answer
268 views
Defining a function to use in another function dependent on similar parameters [closed]
I want to define a variable dependent function which can be used to define another function which depends on the same variable and other variables.
For example, I have a system where I define ...
0
votes
0answers
61 views
Determine class of special function from algebraic constraints?
Consider vectors x_i in arbitrary dimension. Let's say I have an expression in six variables F[x_1,x_2,x_3][x_4,x_5,x_6], which ...
4
votes
3answers
168 views
Find six vectors with rational entries under constraints?
Define six vectors v[i] with i=1,2,3...,6. Each v[i] is six dimensional and all entries in ...
0
votes
1answer
368 views
How does one initialize large arrays in Mathematica with a structured format? [closed]
I want to create a 10 by 10 matrix that increases by 1 every unit across like:
1 2 3 4 5 6 7 8 9 10
11.....
Is there a function that does this without having ...
1
vote
3answers
190 views
How do I make a definition/function/method as I would in Java/MATLAB/Python
I've been trying to figure this out for a few hours now and it's driving me nuts. I am trying to confirm that, after transforming a Schrodinger equation, that the new wavefunctions satisfy the new ...
1
vote
1answer
127 views
Is there a way to convert a string to a Table indicator? [closed]
I have a list like this:
list = {"k1","k2"}
I want to use the elements in the list as Table indicators:
...
1
vote
2answers
69 views
Subsituting expressions for expressions
I'm trying to define functions using other functions, like so:
f[a_, b_] := a/b;
a[c_] := c;
b[d_] := d;
Now what I want to be able to do is two things:
...
1
vote
1answer
67 views
What is the correct idiom for mapping a 0 value in a modulo n expression back to n?
What is the correct idiom for mapping the $0$ value in a modulo $n$ expression back to $n$.
For example if I want to be sure that any integer value maps back to the index for a character in the ...
4
votes
4answers
846 views
Writing a circular matrix
I have two square matrices, $A$ and $B$, of the same size, say, of $m \times m$. What I want is to write a programme/function of three variables, $A$, $B$ and $n$, that outputs the $mn \times mn$ ...
-1
votes
1answer
1k views
Difference between Log and Log10 [closed]
I typed a function :
f := Tan[(1/a)*Log[(Sqrt[x^2 + y^2])]] - y/x
I assigned values:
...
2
votes
1answer
864 views
How to parse string to expression? [closed]
When trying to make a string an expression I see some wrong results:
...
