Help via references please!

This is a discussion on Help via references please! within the C Programming forums, part of the General Programming Boards category; Basically I need to program large (10000 square) sparse symmetric matrices in C efficiently. Can someone point me towards some ...

  1. #1
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    Help via references please!

    Basically I need to program large (10000 square) sparse symmetric matrices in C efficiently. Can someone point me towards some literature on this?

    Could someone also provide a sample bit of code that takes an integer n and malloc's an n x n matrix? It's midday and I still haven't woken up properly!

    Thanks in advance,
    Matt


  2. #2
    Registered User Codeplug's Avatar
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    The FAQ will have some stuff to get you going.

    gg

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    I had a meander through the examples section and the FAQ but nothing struck me as particularly relevant. However, I have managed to find out that sparse matrices are usually dealt with by storing the co-ordinates of the non-zero entries. This is pretty cool and also rather obvious. But my second request still stands.


  4. #4
    Code Goddess Prelude's Avatar
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    I agree that the FAQ really doesn't have much relevant to sparse matrices. Your best bet is to go get an advanced algorithms/data structures book and search google. As for someone giving you code, don't hold your breath. Those of us that are willing and able to write code for such a complex data structure don't want to do it unless absolutely necessary, I know I don't. The last time I wrote code to build and maintain a sparse matrix, I think I vowed never to do it again without exhausting all other alternatives first. Besides, even simple sparse matrix code is too long and complex for these forums.
    My best code is written with the delete key.

  5. #5
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    Originally posted by Prelude
    I agree that the FAQ really doesn't have much relevant to sparse matrices. Your best bet is to go get an advanced algorithms/data structures book and search google. As for someone giving you code, don't hold your breath. Those of us that are willing and able to write code for such a complex data structure don't want to do it unless absolutely necessary, I know I don't. The last time I wrote code to build and maintain a sparse matrix, I think I vowed never to do it again without exhausting all other alternatives first. Besides, even simple sparse matrix code is too long and complex for these forums.
    My code request was just for a little (tiny!) function that takes an integer n and generates an all zero n X n matrix. (ie a tool for going the "long way round")

  6. #6
    ATH0 quzah's Avatar
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    Originally posted by Matt13
    My code request was just for a little (tiny!) function that takes an integer n and generates an all zero n X n matrix. (ie a tool for going the "long way round")
    Take a look here, paying attention to the threads on multi-dimensional arrays.

    Quzah.
    Hope is the first step on the road to disappointment.

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