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Questions tagged [inversion]

The inversion tag is most often used with postings about matrix inversion or data transformations of a similar nature such as color inversion. In addition to the [inversion] tag, you should also specify a tag that indicates the nature of the inversion such as [matrix] or [colors] as most people will do a search not only on the tag [inversion] but also a qualifying tag indicating the kind of inversion.

Inversion in a sequence (A1 . . . An) of n distinct numbers is a pair (i, j) such that i < j and Ai > Aj.
Inversion number of a sequence is one common measure of its sortedness.

Inversion is a general purpose tag indicating a type of transformation to data whether that data is in the form of a matrix, an image (can be considered a matrix of pixels with color values), or some other form of structured data.

When using the [inversion] tag also provide a qualifying tag such as [matrix] or [colors] or other tag which indicates the kind or type of data that is being inverted.

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small Matrix Inversion on CUDA

I need a bit of advice from you, and I hope it won't take a lot of your time. So here is my question: I have a small square dense matrix, with possible sizes 4x4, 8x8, 16x16, and I want to inverse it using CUDA. The special part of the question is…
Ilya Afanasiev
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How to efficiently invert only part of an allocated matrix

I have an algorithm that allocates a complex double matrix "A" with a pre-defined size N x N. The elements are initially zero. I also allocated matrix of size N x N to store the inverse, "A_inv". During the algorithm, elements of "A" get filled. At…
SN1984jm
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clBLAS (OpenCL) matrix inversion

is it possible to calculate a general matrix inversion using clBLAS? Or point me to an example kernel? The matrices to invert will be fairly small (typically 7*7, 28*28 or 84*84), but the inversion will only be a part of larger algorithm, so it…
user4081361
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Inversion on symmetrical relation becomes circular in Coq

One possible way to say that n m : nat are adjacent even numbers in Coq is to define that relation inductively, beginning with 0 and 2. Inductive adj_ev : nat -> nat -> Prop := | ae_0 : adj_ev 0 2 | ae_1 : forall ( n m : nat ), adj_ev n m -> adj_ev…
user287393
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Incorrect number of inversions in array

Could you please help me to find a mistake in my code on C# for counting inversions in array? The count is incorrect. For instance, in array {3, 8, 6, 1} it should be 4, but it's 3. However, it works fine for array {4, 3, 2, 1} and shows 6. Every…
Roman Yashchuk
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Counting number of inversions in an array

For the given problem statement we need to calculate the number of inversion in an array so i tried to apply an algorithm using merge sort and calculating the number of inversion while merging and also at time of sorting. While my code gives the…
InsaynAsasin
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Counting inversions in a vector using mergesort c++

The algorithm is returning an off by one error for some of the inputs I send to it. I wrote the merge_sort and inversion_count with array first; which gave back the right number of inversions. Once I transitioned to vectors I receive off by one for…
user2869622
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Invert selection in SPSS

I have a large table from which I need to drop cases. I need to drop only those properties which were demolished before April 2011 (formatted as 201104). From expeience elsewhere, I would expet this to be dead simple. Select all cases "where…
Bruce Mitchell
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Printing when Searching for Inversions

I'm trying to implement an algorithm that searches for inversions. I'm having trouble printing the updated global variable c. Where should I put the print statement? I'd prefer using a method that involves the boilerplate(?) because I'm going to run…
user2812970
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Circle Inversion with programming languages

How can I find Circle Inversion of any region with programming tools? For an example; consider problem of finding circle inversion for below region : Any ideas or solution would be appreciated, thanks.
Zakhar
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finding inversions of a number array using divide and conquer

I came across a post in SO where the algorithm is implemented in python code .This is a direct implementation of the pseudocode in this article . However,in the pseudocode ,there is a line where count is incremented by the number of remaining…
damon
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Which one is faster / more stable: inverting matrix or solving three systems of linear equations with multiple right hand sides?

I have two equations I'm solving on each recursive round: X = A - inv(B) * Y * inv(B), X = X + A' * inv(B) * A, I solve the problem this way: C = inv(B)Y <=> BC = Y, solve C. D = Cinv(B) <=> DB = C <=> B'D' = C', solve D' E = inv(B)*A <=> BE = A,…
Jouni
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Flex: Inverting LinearAxis values

I have a line chart that is updated every so and so seconds, similar to the one you see in Windows' Task Manager. The chart goes right-to-left, with the most recent data on the right, and going leftwards. How would I invert the values of the X axis…
Aethex
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Optimization of color inversion - Python Tkinter library

I attempted today to create a Python code to invert the colors of a .gif image using the Tkinter library. The code works and does exactly what I expected, but it takes about 50 seconds to run on a 3.4ghz processor. I'm having trouble seeing what I…
Mortimer McMire
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How to get a shape that covers the entire canvas with a void as the original shape (inversion)

I'm trying to get, by the initial coordinates (I put down the points myself, see the image below), in fact, to get a figure that will become a kind of emptiness for the new one. So that the new one covers the entire canvas, having a void inside in…
Timur Musharapov
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