Questions tagged [index]
Questions about functions with intrinsic part index such as SparseArray, Part and Indexed or iteration variable indexes such as MapIndexed, Sum and Product.
9
questions with no upvoted or accepted answers
3
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157
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Efficiently get positions of Query results
I have some very large Datasets. Is there any efficient method of getting the positions of results found in a Query? That is, without using ...
- 3,780
2
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0
answers
117
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Typography of Mixed Tensor Index Notation
How can one properly and quickly write a mixed "tensor" such as $\Gamma{}_{1}{}^{2}{}_{3}$?
Shortcuts such as esc Gamma esc, Ctrl+^, Ctrl+_ are prefered. I intendd to use this in an inline equation ...
- 1,883
2
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0
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763
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Sum over multiindex
I would like to calculate a sum over some multi-indices, that follow a specific pattern.
$$\sum\limits_{1\le i_1<i_2<...<i_k\le N} A(k,i_1, i_2, ..., i_k).$$
$A$ is a fix expression of the ...
- 21
2
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0
answers
123
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ParallelDo with doubly-indexed iterators
What is the reason that ParallelDo works with singly-indexed iterators, but not doubly- or more-indexed iterators? For example, the code
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1
vote
0
answers
368
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Assigning Values of Indexed Variables to Arrays
New to mma. I have assigned the results of using Solve to solve 5 variables to 5 indices of a new variable:
...
- 63
1
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0
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115
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0
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39
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One as Subscript and Supersripts
I am trying writing code with a lots of symbols and their products.
There is an issue with the appearance of "1" as an index. e.g.
Subscript[[Delta], 1 n]
Why "1" does not appear ...
- 575
0
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0
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28
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How to define an index list of local variables for arbitrarily long
Suppose initially I have a list that looks like
list1 = {A, B, C}
where the elements A, B, C are all matrices. I want to substitute all the three elements by list1 ...
0
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0
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50
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Defining list of data
I need to define a list of parameters A[i] where i runs from 1 to some integerN. The ...
- 479