Questions tagged [dot]
The dot tag has no usage guidance.
49
questions
0
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0
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35
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Patterns with Dot [duplicate]
I would like to understand the behavior of Dot to build patterns with it. Could someone tell me what is going on in these examples?
...
- 998
4
votes
2
answers
88
views
Speed up sparse Hermitian matrix-vector product
I am interested in speeding up as much as possible the dot product in the specific case of a multiplication of a $n\times n$ sparse hermitian matrix $H$ (where $n$ is typically large, let's say $\...
- 283
3
votes
1
answer
108
views
Factor constants out of multiple dot products
I have expressions of the type
(-y A.A).(-y A.A).(A x).(A x) (* Example 1 *)
(-y A.A).(-y A.A).(A x) (* Example 2 *)
The number of parenthesis factors can vary, ...
- 249
0
votes
3
answers
126
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Scalar product of vectors using dummy indices
How can I rewrite the following expression
$expr1= (A\cdot B)(C\cdot D)(E\cdot F) + (A^\prime\cdot B^\prime)(C^\prime\cdot D^\prime)(E^\prime\cdot F^\prime) +\cdots $
in terms of the components as
$...
- 105
2
votes
2
answers
207
views
Plotting a discrete set of data points and continuous plot together [closed]
I am struggling to plot discrete set of lines ( black dashed line around the black point) along with a continuous plot ( blue and yellow curves).
Following is the problem:
Basically i want to plot ...
- 179
3
votes
2
answers
281
views
Speed up dot product with shifted vector
I have to calculate multiple dot products between a vector and consecutive part of another (longer) vector, shifted at certain number of elements. Naive implementation takes about 0.1 seconds.
...
- 959
8
votes
2
answers
398
views
Dot Product and Simplification
How to simplify the expression
a b . x/((a b) . x)
Where a is a scalar and b and x are vectors.
I have tried the usual Simplify, FullSimplify, TensorExpand etc. ...
- 795
1
vote
0
answers
136
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Why is the dot operator not just matrix multiplication?
It seems to me Mathematica does not have an inbuilt matrix multiplication operator. The dot operator fails as such, as is even noted under "Possible Issues" in its documentation it ...
- 111
2
votes
0
answers
68
views
Dot product of arrays that are members of the same list
Lets say I have a list of n arrays:
n=3;
list = Table[RandomInteger[{-10, 10}, {2, 2}], n];
I would like to calculate the matrix corresponding to:
...
1
vote
1
answer
74
views
2
votes
1
answer
71
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Simplifying expressions with dot or non-commutative product (without the help of NCAlgebra)
I have two expressions (with dot and non-commutative product):
$f=J^T.x+J.x$
$g=J^T**x+J**x$
I want to simplify them and get the following expressions:
$f=(J^T+J).x$
$g=(J^T+J)**x$
In an attempt to ...
- 2,444
0
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1
answer
778
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dot product and norm [closed]
Can you solve the following problem in mathematica program? Thank you.
Let x=(x1,x2,x3),y=(y1,y2,y3) and ⟨x,y⟩=x1y1+2x2y2+x3y3 be an inner product in a three-dimensional real vector space.
Define the ...
- 13
2
votes
0
answers
77
views
dot product of one thousand matrices [closed]
I have a time dependent matrix. In a thousand different times with the same time intervals I get the values of the matrices. Now, how can I DOT Product these thousand matrices in time order??
0
votes
1
answer
113
views
Want to multiply same matix n times using dot product
I want to multiply same matrix using dot product for n times.
U[n_]:=Apply[Dot,[MatrixExp[-I H ]],{i,0,n}]
- 35
0
votes
0
answers
92
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Dot Product doesn't behave like normal function
I am trying to slightly modify the Dot function by treating it like a usual function, but soon I notice something weird about it.
Suppose there is a set ...
- 543