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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 retrieve the git branch name that was built by Jenkins when using inverse branch selection strategy?

We have one Jenkins job which builds every branch except master when there are new commits. This behavior can be configured via git plugin's 'choosing strategy:inverse' so that it listens to every branch except a specified branch. This functions…
harish
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find command and inverse regex

I've looking for a way to express this command that excludes all executable perms except for those files ended in ".EXE" I've trying to solve it using the "find" command and -exec, please. Thanks. The command I tryed, and other versions of the same,…
DrBeco
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Inverse Map where getValue returns a List

I would like to transform a Map> so it becomes Map. If it were just Map it is easy in Java8; stream().collect(k -> k.getValue().getMyKey(), Entry::getKey); But this will not work because getValue…
cbm64
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How to calculate the inverse of the log normal cumulative distribution function in python?

How do I calculate the inverse of the log normal cumulative distribution function in python? I'm trying to translate some functions from Excel that uses the function [LOGINV][1] For example LOGINV(0,005;2;0,5) yields 2,0382373 where 0,005 is the…
GeoPy
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How simplifying fractions in matrices with sympy?

I'm using sympy to find a matrix's inverse. I've the next problem. When I compute the inverse of matrix A and I want prove it, I got a matrix with fractions; I mean >> import sympy >> from sympy import pprint >> from sympy.abc import * >> import…
Yakz
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Fitting an inverse function

I have a function which looks like: g(x) = f(x) - a^b / f(x)^b g(x) - known function, data vector provided. f(x) - hidden process. a,b - parameters of this function. From the above we get the relation: f(x) = inverse(g(x)) My goal is to optimize…
Paul
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Implementing Trigonometric Inverse Functions in c#

I'm trying to implement inverse trigonometric functions in a C# application. Obviously I'm not talking about simple inverse sin, cos and tan seeing as those are all provided by the Math class. What I'm looking for is the inverses for sec, cosec…
RobV
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Java inverse modulo 2**64

Given an odd long x, I'm looking for long y such that their product modulo 2**64 (i.e., using the normal overflowing arithmetic) equals to 1. To make clear what I mean: This could be computed in a few thousand year this way: for (long y=1; ; y+=2)…
maaartinus
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Inverse fourier transformation in OpenCV

I am new in OpenCV and image processing algorithms. I need to do inverse discrete fourier transformation in OpenCV in C++, but I don't know how. I searched over internet and I didn't find answer. I am doing fourier transformation in my program with…
rwrx_
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Inverse of preg_quote in PHP

I need to write a function that does exactly opposite of preg_quote function. Simply removing all '\' did not work because there can be a '\' in the string. Example; inverse_preg_quote('an\\y s\.tri\*ng') //this should return "an\y s.tri*ng" or…
ibrahim
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jQuery a solution between children() and find(): anything that looks like closest()?

Based on the different answers received, the only solution using jQuery without implementing our own selector function is a basic selector with ":first" or followed by ".eq(0)" for jQuery. I wanted to know if their were any kind of max depth option…
Micaël Félix
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Second Self-To-Self relationship in Entity Framework

Assume we have a domain class public class Incident { [Key] public virtual int IncidentId { get; set; } [Display(Name = "Parent Incident")] public virtual Incident ParentIncident { get; set; } [Display(Name = "Related Claim")] …
Maxim V. Pavlov
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Absolute angle between lines using inverse cosine

I want to calculate the angle between two lines formed by three points(one of the points is the point of intersection of the two lines) using inverse cosine function as follows: CGFloat a = initialPosition.x - origin.x; CGFloat b = initialPosition.y…
tipycalFlow
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Modelica annotation inverse of function is ignored

Problem: the inverse annotation of a function is ignored and the inverse is computed numerically. According to Modelica Specifications it is possible to specify an inverse of a given function. In order to test this functionallity I tried with a very…
DarioMangoni
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How to generate a pseudo-random involution?

For generating a pseudo-random permutation, the Knuth shuffles can be used. An involution is a self-inverse permutation and I guess, I could adapt the shuffles by forbidding touching an element multiple times. However, I'm not sure whether I could…
maaartinus
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