• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
313230

Finding float elements have the same value in an array

4 posts in this topic

Hi,

I have a float array with random numbers, what is the best method to find positions of elements that have the same value (the difference is within an epsilon)

Regards
1

Share this post


Link to post
Share on other sites
Hmm, I would do this in three steps, I think.

In the first step I would create an int array to store all the indexes for each value in the float array and create an exact copy of the float array(assuming you still want it to be intact and have the values not being moved around).

I would then implement some sorting algorithm(which one I decide to use depends on the amount of numbers and how important the efficiency is required to be). This algorithm will then sort from smallest to largest in my copy of the float array and at the same time swap the corresponding value in the int array I created.

When this is all done my copy of floats will store its values from smallest to largest and my int array will have the indexes of these values corresponding to their initial value in the original float array. Then I would need to check the first element in my copy and compare it to the next element. If they are not the same I would stop checking that first element since the array will be stored in order of size. If the next element isn't the same size then there are no values that are the same size as this one. I would then continue with the next element.


So TL;DR:

1. Create a float array which will be a copy of your float array to check. Also create an int array to store the indexes of the float array. This int array will simply have 1,2,3,4,5 etc. The use of the int array will come when sorting the float array.

2. Implement a sorting algorithm to sort the copy of the float array by size. Move their corresponding index value in the int array. Example: number 38.2 is on index 3. 38.2 is the lowest number generated. Move the number 38.2 to position float array[0] in your copy. Move the value 3 to position int array[0] in the int array.

3. Go through each index in your sorted array and compare it to the element next in that array. If that value is not equal then your element does not appear more than once in your array. Go to the next element, i.e element [1]. Compare it against element [2] and if they are the same, then do what ever you are supposed to do if there are more than one of an element. In the int array at position [2] the value of its corresponding index in the original float array will be listed.

Note: This is a solution on top of my head and is quite a lot of work ^^ There are probably several other efficient ways of doing this, but this is the first solution that came to mind.
1

Share this post


Link to post
Share on other sites

int x, y;
float array[ ARRAY_SIZE ];

for(x = 0; x < ARRAY_SIZE; x++)
    for(y = x+1; y < ARRAY_SIZE; y++)
        if(fabs(array[x] - array[y]) < EPSILON)
            printf("array[%d] (%f) ~ array[%d] (%f)\n", x, array[x], y, array[y]);
Edited by radioteeth
1

Share this post


Link to post
Share on other sites
for some reason the float array line wasn't showing ARRAY_ part, so I added spaces around it so it would render properly.
1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0