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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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Reversing Diagonal In Matrix

Title says it all, I developed this diagonal method that searches the Matrix 'matrix' and goes from the Center to the far right corner. I also have it another set from the center to the left. I now have the question, how would I make it reversed,…
Abszol
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efficient way to invert large correlation matrix

Let us say I have a very large correlation matrix of this form: t1.rep1 = rnorm(n=100,mean=10,sd=) t2.rep1 = t1.rep1 + rnorm(n=100,mean=3,sd=2) t3.rep1 = t1.rep1 + rnorm(n=100,mean=2,sd=2) t1.rep2 = rnorm(n=100,mean=2,sd=1) t2.rep2 = t1.rep2 +…
Dnaiel
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Cascading with traceability using NHibernate?

I have read on the inverse and cascade mapping attributes, and would like to know: Whether is it possible to use them in my scenario? And if it is, How to parameterize them accordingly? Let's say I have two classes, Customer and Invoice, both…
Will Marcouiller
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Inverse, exponentially spaced representation of a count field?

var minCount = 10; // Used as 0, anything below 10 uses will be ignored User hasMany Attributes Attribute (id, value, count, worth) // Count - number of users who associate with this attribute // Worth - float 0.1 (or a better non-zero number?) to…
StringsOnFire
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Can you help me understand the inverse Fourier transform work?

I am trying to learn about Fourier transforms and using MATLABs FFT function I can transform a recording of me saying '1 2 3' into the frequency domain. As I understand it the resulting file contains a set of complex numbers which hold the magnitude…
thecolin
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How to compute the inverse of a close to singular matrix in R?

I want to minimize function FlogV (working with a multinormal distribution, Z is data matrix NxC; SIGMA it´s a square matrix CxC of var-covariance of data, R a vector with length C) FLogV <- function(P){ (here I define parameters, P, within R and…
Maria D
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Choosing tick locations for a graph in '1/x space'

I'm trying to graph some data points. The X coordinates tend to be inversely proportional to the Y coordinates, so I decided to try graphic in '1/x' space (replace every x with 1/x). This makes the graph a lot more evenly spaced, but there's a…
Craig Gidney
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Core Data Relationships - setting up one relationship using multiple similar types

I am setting up Core Data in my app programmatically, and have come across an "issue" (not exactly an issue, but was wondering if anyone had found a nice way around it). I have a base class FormElement (which extends NSManagedObject). I then extend…
lampus_maximus
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AVR C - Why inverting values?

I have extremly stupid question, but I wasn't able to find answer to it. I am starting AVR programming and I have one question, regarding code example I've found. int main(void) { DDRA = 0xFF; // Setting all port A pins for output for(;;) { …
user1772574
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Mathematica plot is a straight line

So I'm trying to knock out this last problem, and I'm following my teacher's guide but my graph seems to still be off, the problem is: Use the FindRoot command in Mathematica to define an inverse function g(y) to y = f(x) = 3x + tan(x) with the…
user2302876
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jquery inverse of div selector

I'm trying to get an event when a user selects a row and drops it outside a jquery grid. This is the drop function for a drag/drop happens within the grid, which works perfectly fine - $(".grid-canvas") .on("drop", function (e,…
snakepitbean
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NHibernate not inserting child entities in one-to-many

I have Customer and Profile classes, where one Customer can have many Profiles. I am using following NHibernate override classes with them: public void Override(AutoMapping mapping) { mapping.Table("[Customer]"); …
Trebor Sadnib
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CUDA __syncthreads(); not working; inverse in breakpoint hit order

I have a problem, I think with __syncthreads();, in the following code: __device__ void prefixSumJoin(const bool *g_idata, int *g_odata, int n) { __shared__ int temp[Config::bfr*Config::bfr]; // allocated on invocation int thid =…
user2390724
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Use of pattern attribute in HTML input

I have this example for pattern in HTML pattern="[a-zA-Z0-9-_. ]{1,30}". This means that only letters numbers and -_. are allowed, but I want to make a pattern like in the preg_replace which allows everything but not [ <>/\:*?"|]. So how can I go…
user2303038
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finding difference between two rotation matrices

I am having following problem, I have developed code for converting the large array of euler angles to rotation matrices, my data is phi1,phi and phi2 values like as follows phi1 phi phi2 2 3 5 1 2.2 4.3 3 4 5 .....there are…
rcty
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