Performance in Mandelbrot Set Computation
I want to have a nice poster of a Mandelbrot set, say 75×50 cm². At 300 DPI printing resolution, I need to compute a lot of pixels:
Einträge über Performance
Drosselung einer CPU
Die CPU in meinem Laptop wird recht schnell 96 °C warm. Ich wollte mal schauen, wie stark es dann gedrosselt wird. Also habe ich es mit mprime ausgelastet und man kann gut sehen, wie der durchschnittliche Takt anfängt von 3 GHz abzuweichen, sobald die Temperatur so 90 °C erreicht hat:
qsort vs. std::sort
When you have an array with some data structure that you would like to sort, you are looking for a sorting algorithm in the standard library.
Test of various clock implementations
There are a couple ways to measure the real (wall) time that some part of the
code has used. I know the standard clock() from time.h and all the chrono
from C++11. Then MPI and OpenMP have their own routines as well.
Matrix structure in C
I know of two ways to represent a matrix in plain C. One is to have arrays in
arrays. So the matrix is an array, where each entry contains a row of the
matrix. You access the entries with something like matrix[row][col].
Efficiency of the `pow` function
Someone said that using pow(x, 2) is always more inefficient than using
x * x. Well, there are two things to remember:
include() vs. Functions
A while ago, I had an intriguing conversation with somebody who disclosed some secrets about PHP. He told me that he does not use functions but rather include files, since a function file would have to be included and since something has to be included anyway, there was no need for the function after all.