What is the fastest way to transpose a matrix in C

I have a reasonably large matrix that I need to transpose.

Assume, for example, that my matrix is

a b c d e f
g h i j k l
m n o p q r

I want the result be as follows:

a g m
b h n
c I o
d j p
e k q
f l r

What is the fastest way to do this?

Jul 15, 2022 in C++ by Nicholas
• 7,760 points • 692 views

No answer to this question. Be the first to respond.

Your answer

Your name to display (optional):

Email me at this address if my answer is selected or commented on:

Privacy: Your email address will only be used for sending these notifications.

What is the best way to use a HashMap in C++?

The ordered and unordered map containers (std::map and std::unordered map) are included in the standard library. The items in an ordered map are sorted by key, and insert and access are in O (log n). For ordered maps, the standard library often use red black trees. However, this is only an implementation detail. Insert and access are in O in an unordered map (1). It is simply another term for a hashtable. An illustration using (ordered) std::map: #include <map> #include <iostream> #include <cassert> int main(int argc, char ...READ MORE

answered Jun 10, 2022 in C++ by Damon
• 4,960 points • 857 views

0 votes

0 answers

What is the C++ function to raise a number to a power?

What's the best way to raise a n ...READ MORE

Jun 1, 2022 in C++ by Nicholas
• 7,760 points • 541 views

0 votes

0 answers

What is the easiest way to initialize a std::vector with hardcoded elements?

I can make an array and initialise&nb ...READ MORE

Jun 27, 2022 in C++ by Nicholas
• 7,760 points • 600 views

0 votes

1 answer

Is there an easy way to make a min heap in C++?

Use make heap() and its buddies from algorithm>, or priority queue from queue>. Make heap and friends are used by priority queue. #include <queue> // functional,iostream,ctime,cstdlib using namespace std; int main(int ...READ MORE

answered Jun 27, 2022 in C++ by Damon
• 4,960 points • 1,047 views

0 votes

0 answers

What is the difference between cout, cerr, clog of iostream header in c++? When to use which one?

I looked up the differences between cout, ...READ MORE

Jul 27, 2022 in C++ by Nicholas
• 7,760 points • 732 views

0 votes

1 answer

Are virtual functions the only way to achieve Runtime Polymorphism in C++?

fprintf is a polymorphism function in the C programming language. It can print to a file, stdout, a printer, a socket, or whatever else the system can represent as a stream if you supply it different handles. FILE* file = fopen("output.txt", "w"); ...READ MORE

answered Jun 21, 2022 in C++ by Damon
• 4,960 points • 489 views

0 votes

1 answer

Why would anyone use set instead of unordered_set?

Unordered sets must compensate for their O(1) ...READ MORE

answered Jun 1, 2022 in C++ by Damon
• 4,960 points • 2,963 views

0 votes

1 answer

What is the difference between std::__gcd and std::gcd?

I done some research about this. The ...READ MORE

answered Jun 10, 2022 in C++ by Damon
• 4,960 points • 1,779 views

0 votes

1 answer

Lower and Upper Bound in case of Decreasing/Non-ascending vector

Both std::lower bound and std::upper bound must have an increasing (non-decreasing) order as their objective. By giving a comparator as the 4th parameter of the functions, you may modify the meaning of "growing." To work with descending vectors, use std::greater. #include<iostream> #include<vector> #include<algorithm> #include<functional> using namespace std; int main() { ...READ MORE