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I'm developing an estimation algorithm in C++ and performance is key. Basically there is loop where in each iteration, a decision is made on whether to add a column vector to a matrix or to remove one.
I have implemented my own matrix and vector classes and used Intel MKL for matrix operations. However after the first version I'm now looking into using Armadillo.
I would like to know what the best strategy is for dynamic growing matrices inside loops. I know the maximum size of the matrix, so I could preallocate.
First of all, is there another matrix library you would recommend other than Armadillo for small matrices (50 X 50)?
Secondly, what would be the best way to tackle this problem using Armadillo?
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I'm trying to think of some interesting, reusable way to implement big integers using passed amount of bytes or resizing themselves when needed. I have no idea how to make it optimal in any way tho. Are there any tricks I could use, or do I have to simply work on those numbers bit by bit while adding/multiplying/dividing?
edit: if it is important, I need it to safe text as number in base 10 so I can play with some ideas for encrypting it
Use The GNU Multiple Precision Arithmetic Library. If you try to reinvent the wheel you will end up with a square.
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How the glClearBufferData is implemented internally? Does it uses CPU (sequential clearing) or GPU (parallel clearing)? If I have big buffer (several megabytes), what is the best way (in terms of time complexity) to clear it? Maybe customized rendering pass, that sets to buffer desired value in fragment shader, would be more efficient? If there is no single solution, please, advise me some materials. Help me please ! :)
As with most OpenGL functions, the implementation is provided the freedom to implement it in whatever way it feels is best for the hardware. You aren't permitted to know about those details.
If you need to clear a buffer to a specific value, just call the function and let the implementation do its job.
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I'm needing a elliptic filter code in c or c++, this code should filter a float input array.
Does anyone there have any code to do it?
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If you use e.g. MATLAB to design your filter (using e.g. the ellip function), you can take the resulting filter coefficients and very easily implement the filter in software (it's just a matter of multiplying the float values by the coefficients and following the rational filter equation).
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I was doing some work handling a lot of information and my partner told me that I was using too many matrices to manipulate the variables of the problem. The idea was to use one dimension arrays int a[] instead of the 2 dimensional arrays int b[][], to save memory and processing speed of the algorithm. How certain is that this change will accelerate the speed of execution or compilation of my code in c ++?
Your question invites to guesswork, but:
How certain is that this change will accelerate the speed of execution or compilation of my code in c ++?
Prognosis is extremely uncertain. The only proper response is to measure.
Measuring is knowing. You can quote me on that.
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I'm implementing the Chessboard class to represent the chessboard. I've to implement the transformations (reflections and rotations) on the chess board possible.
The possible transformations includes the combination of:
1. Vertical Reflection
2. Horizontal Reflection
3. Diagonal Reflection
Thus, we've 8 possible transformations for chess board.
There are 64 squares on the Chessboard numbered [0..63].
Thus, to represent the total resulting values after the transformations is 8*64 (No.of Transformations * Chessboard_Size).
There are two fundamental ways to represent the transformed_board using Arrays:
One-Dimensional Array with transformed_board[8*64]
Two-Dimensional Array with transformed_board[8][64]
Questions:
Which approach is better?
What are the pros and cons of each approach?
How will effect the performance with respect to time factor?
The memory layout is the same for both, so there isn't really any "real" difference whatsoever. It's just a matter if whether you want the compiler to do the offset calculation for you or not, so just go with the syntax you like better.