Stack Overflow
Stack Overflow

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 .

474 questions
0
votes
2 answers

Inverse function after sqare and multiplication

I'm trying to write two inverse functions. If we pass to function A value 10 it returns for example 4,86 and if we pass that number to function B it should give us back original 10. I'm using something like this in function A: output =…
Martin
  • 145
  • 6
0
votes
1 answer

Core Data inverse relationship and deleting unused objects

I have a Core Data model similar to this: When a Webgallery or Article object gets saved, it may use one or many pictures. They can use the same photographical subject but maybe in different sizes. I don't save pictures that don't get used in…
Norbert
  • 4,239
  • 7
  • 37
  • 59
0
votes
1 answer

What is the difference between cascade and inverse in Hibernate?

Many people like to compare between inverse and cascade, but both are totally different notions (at the bottom of this page). In Hibernate, only the “relationship owner” should maintain the relationship, and the “inverse” keyword is created to…
Tiny
  • 27,221
  • 105
  • 339
  • 599
0
votes
1 answer

Cascading delete for optional inverse joins

There is a following simplified mapping for one of our entity classes:
JustAMartin
  • 13,165
  • 18
  • 99
  • 183
0
votes
1 answer

Apple FFT Accelerate Framework Inverse FFT from Array of Real Numbers

I am using the accelerate framework FFT functions to produce a spectrogram of a sound sample. This part works great. However, I want to (effectively) manipulate the spectrum directly (ie manipulate the real numbers), and then call the inverse…
raeldor
  • 503
  • 3
  • 11
-1
votes
1 answer

php date string to timestamp - inverse_date()

I'm looking for a function that does the inverse of date(). Meaning: $timestamp = inverse_date($format_string, $date_string); $d = date($format_string, $timestamp); if ($d === $date_string) { echo 'This is what I want'; } Problems I've run into…
Gavriel
  • 18,880
  • 12
  • 68
  • 105
-1
votes
3 answers

Inversion of a discrete function function.

I have a table about inverse gamma correction these are the values coresponding from 0 to 256 down there. I need a way to calculate the inverse of this function -> something like 0, 2, 6, 9, ... I would appreciate it, if someone could tell me a…
Dimitar Slavchev
  • 1,597
  • 3
  • 16
  • 20
-1
votes
1 answer

Matrix Inverse broadcasting

I am trying to calculate Rij = Aij * Bij/Cij by Numpy broadcasting. B1 * np.linalg.inv(C1) gives a singular matrix error. I have also tried doing this. It gave me some values but I am not super sure if it is correct. D = B1 / C1[..., None] import…
sansa
  • 21
  • 4
-1
votes
2 answers

How to check if a dictionary is invertible

I am working on a question that requires to point out the problem in a function that determines whether a dictionary is invertible (for every value appearing in the dictionary, there is only one key that maps to that value) or not. The question is…
rrr
  • 361
  • 4
  • 13
-1
votes
2 answers

I'm getting error in my c++ code! & How to find determinant and inverse of matrix in c++?

I'm trying make matrix calculator. in which i almost done every operation which required in matrix. So now i'm trying to code to find determinant and inverse of matrix, but im getting error like :- argument of type "int" is incompatible with…
Vinayak Thube
  • 3
  • 3
-1
votes
3 answers

How do i implement the push pop peek methods for an inverse array?

Create a class called inverse_Stack where our 'stack' is organized in such a way where the first/"bottom" element is located at index (-1). Each element pushed is placed into the array slot before the [current] top-most element. if(size=0)store at…
Ricky
  • 11
  • 5
-1
votes
1 answer

How can I inverse my column in Symfony 4 (ManyToMany)?

This is my entity Fields:
peace_love
  • 6,229
  • 11
  • 69
  • 157
-1
votes
1 answer

inverse the binarized dataframe to original categorical values after un-pickling

I am trying to solve a classification problem where the label column contains string values. Steps followed in Training the model :- Converted the dataframe to binarized values using pandas.get_dummies. Trained the Randomforest classifier…
Jenny
  • 51
  • 7
-1
votes
1 answer

Inverse of a 4x3 matrix in python

I'm reimplementing a closed source 3d library called noesis. It exposes a python file with all of the basic classes. All of the implementation details are actually hidden. The implementation is compiled so I can't preview it. I want to implement one…
Andrzej Trzaska
  • 43
  • 2
-1
votes
3 answers

Python inverse endswith() method

I hava a very simple piece of code, similar to this: if var1.endswith("/"): print("whatever") What can I do to inverse the if, except using an else statement? Like I want to print "whatever" if var1 does not end with "/" Thanks,
dmuensterer
  • 1,875
  • 11
  • 26
1 2 3
…
31 32