Questions tagged [expression-construction]
The expression-construction tag has no usage guidance.
108
questions
56
votes
3
answers
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How to form a block-diagonal matrix from a list of matrices?
For example, like this:
I know Join works, but it is a bit troublesome for multiple matrices. I also tried DiagonalMatrix, but ...
- 2,345
22
votes
4
answers
1k
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 ...
- 1,069
19
votes
11
answers
2k
views
Efficient way to build a certain square matrix
For odd n I'm looking for a short and swift way to construct with (f.e.)
n = 3
n = 11
<...
- 81.5k
19
votes
2
answers
786
views
Additive SparseArray Assembly
The goal is to assemble a SparseArray in an additive fashion.
Let us assume we have a large List of indices (some will be ...
- 758
15
votes
2
answers
2k
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Need help coding/creating a recursive list
I have two lists A and B, each with 99 real numbers. I want to form a list, C, whose ...
- 153
11
votes
4
answers
221
views
Constraint syntax compaction
Is there a more compact way to represent these constraints:
NMaximize[{a+b+c,a <= 5 && b <= 5 && c <= 5...
- 399
11
votes
1
answer
307
views
Why can't a string be formed by head String?
Since everything is an expression in Mathematica, why must a string object be formed by "abc" but not by a String[abc] ...
- 1,235
11
votes
0
answers
2k
views
Resources on Mathematica and strong AI (a.k.a. AGI) [closed]
David Deutsch (physicist / quantum computing theorist) wrote an article for Aeon Magazine last year: On Artificial Intelligence that got me thinking.
The article assesses and critiques the ...
- 14.5k
10
votes
4
answers
1k
views
10
votes
3
answers
184
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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}
\...
- 1,641
9
votes
5
answers
2k
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 ...
- 12k
8
votes
11
answers
1k
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Ragged Diamonds
diamond[n_Integer] :=
Table[1, {#}] & /@ (Range[n]~ Join~Range[n - 1, 1, -1])
diamond[5] // MatrixForm
How could a more functional, "tablefree", solution ...
- 81.5k
8
votes
2
answers
265
views
Using `With[...]` with a list specification as a variable [duplicate]
If you have some defined function, say f[a_, b_ c_, x], one can initialize this by using With[...] as
...
- 2,520
8
votes
3
answers
1k
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How to create a large sparse block matrix
I need to generate a very large sparse block matrix, with blocks consisting only of ones along the diagonal. I have tried several ways of doing this, but I seem to always run out of memory.
The ...
- 81
7
votes
5
answers
654
views
Elegant method of generating this matrix?
Good evening,
I need to determine an elegant (as possible) method of computing an $n\times n$ matrix below (the matrix shown is just a $16\times16$ example). I've been toying with ...
- 771