29 lines
687 B
C++
Executable File
29 lines
687 B
C++
Executable File
#include <iostream>
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#include <string>
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using namespace std;
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float Q_rsqrt( float number )
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{
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long i;
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float x2, y;
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const float threehalfs = 1.5F;
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x2 = number * 0.5F;
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y = number;
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i = * ( long * ) &y; // evil floating point bit level hacking
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i = 0x5f3759df - ( i >> 1 ); // what the fuck
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y = * ( float * ) &i;
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y = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration
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y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, can be removed
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return y;
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}
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int main()
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{
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int number;
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cin >> number;
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cout << Q_rsqrt( number );
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return 0;
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} |