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Questions tagged [inverse]

In mathematics, a function y=f(x) tells us how to map input x to output y. Inverting a function (or an operator) is attempting to find a function f¯¹ that maps y to x, such that x=f¯¹(f(x)).

In mathematics, a function y = f(x) tells us how to map input x to output y. Inverting a function (or an operator) is attempting to find a function f -1 that maps y to x, such that x = f -1( f(x) ).

It is not always possible to find the inverse map, and sometimes it does not even exist.

One of the most common inverse problems is inverting an n × n matrix: only square matrices A with det(A) ≠ 0 have an inverse matrix A-1. See .

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How to tackle this Inverse Relation homework?

Here is my assignment: Write a function inverse(rel) that takes a relation rel and returns the inverse relation of the relation rel. The inverse relation InvsetR of the relation R is dened as InvsetR = {(x, y) ∈ S × S |(y, x) ∈ R)}.…
Margarita
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Trying to calculate the inverse of a square matrix

R 0.99.893 solve() on Windows 10 - Error in solve.default(a) Trying to calculate the inverse of a square matrix, but getting an error: a <- matrix(1:16, 4,4) solve(a) Error in solve.default(a) : Lapack routine dgesv: system is exactly…
gmkaizen
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Inverting a 3 x 3 Array and displaying it Java

So, I'm trying to create a program that captures 9 numbers in a 2D array, being of size 3 x 3. After capturing all the numbers, they are re-arranged, reversed, and displayed. So if a user entered: 1 2 3 4 5 6 7 8 9 It should be reversed as this: 9…
David H
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inverse of a matrix by gauss elimination method

How to find the inverse of a matrix? I am trying to use the Gauss elimination method. I know how to solve it by hand, but unable to understand how to code.
Shubh Gupta
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Inverse function of a given function

I have a function with two inputs x and y which returns z based on some conditions (which rely on the values of x and y). Something similar to the following pseudocode. f(x, y) if x < a && y < b return z=x+y; else if x >= a && x < c…
Ali Abbasinasab
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Inverse Count Issue C#

Not Quite what the title suggests, what i need is a way to count a string backwards like string i = "3027" i[0] = label1.Text Result = 7 not 3 is there a way? not sure if you need my code or not its not really important.
user3439904
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Tridiagonal Matrix Inverse C

Hello I am trying to make an inverse function for a tridiagonal matrix in c, but my code is giving me a segfault error. The code is /* Inverse of a n by n matrix */ #include #include #include double J[3][3]; double…
user2898810
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How to calculate sin inverse (arcsin) in VHDL?

I am using Altera De0 nano Soc FPGA, and Quartus 16.1 lite edition. After doing a search on internet, I found that to get sin, cos and atan Altera's CORDIC IP core can be used directly. And also found lookup table (LUT) can be used for sin or cos…
komto909
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Create inverse Kaplan Meier curve with response percents and time

I am trying to create an inverse KM plot of the time it takes for patients to respond to drug therapy. Time response 3 57 4 35 4 85 4 90 5 55 6 65 6 89 6 72 9 97 9 89 9 98 10 99 10 92 13 99 14 50 15 97 18 60 21 70 25…
Reeham
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Creating an array that starts at n and ends at 0

I'm having difficulty with the action below. I'm not sure how to reverse the array index starting at n and working down to 0. Can someone help me understand this? I'm thinking of using a for loop, but I can't quite visualize how I would do…
Nick94107
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get wrong inverse matrix from both solve() and ginv()

`I am trying to get an inverse matrix of [,1] [,2] [,3] [1,] 1 rou 0 [2,] rou 1+rou^2 rou [3,] 0 rou 1 the inverse matrix calculated by hand should be 1 rou rou^2 1/(1-rou) rou 1 rou …
Yukun
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Inverse matrix in Haskell

I just started to learn Haskell. And I have a question. I trying write a function to find the inverse matrix. My type of matrix looks like that: data Matrix a = M { nrows :: !Int , ncols :: !Int , mvect :: V.Vector (V.Vector a) }…
anthonyS
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Inverted Index in Python not returning desired results

I'm having trouble returning proper results for an inverted index in python. I'm trying to load a list of strings in the variable 'strlist' and then with my Inverse index looping over the strings to return the word + where it occurs. Here is what I…
user2565601
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Get NetPBM negative image (Math formula)

I have a file of integer values that range from 0 to 255. A value of zero means black pixel while a value of 255 means a white pixel. Values in between are "gray-like colors". I am searching for a way to invert that file so that 255 gets transformed…
Flame_Phoenix
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Access Violation only with large values, but working with small ones

I am working on a C method to find the inverse of a number mod n, and it works perfectly fine when for example I call this method with 6.0 and 65537.0, it gives me the correct result, even when showing a warning for dereferencing the pointer,…
Miguel Rodriguez
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