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  1. #include <string>
  2. #include <stdio.h>
  3. #include <cmath>
  4. #include <assert.h>
  5. #include <vector>
  6. #include <stdlib.h>
  7.  
  8. //#define USE_DOT
  9. //#define USE_SSE
  10.  
  11.  
  12. static const float CMP_EPS = 0.1f;
  13.  
  14. typedef float v4sf __attribute__ ((vector_size (16))); // vector of three single floats
  15.  
  16. struct f3vector {
  17.     union
  18. 	{
  19. 		v4sf v;
  20. 		struct { float x,y,z,w; };
  21. 		struct { int ix,iy,iz,iw; };
  22. 	};
  23. };
  24.  
  25.  
  26. struct float3 : public f3vector {
  27. 	float3(const float _x, const float _y, const float _z) {
  28. 		x = _x; y = _y; z = _z;
  29. 	}
  30.  
  31. #ifdef USE_SSE
  32. 	float3& operator+= (const float3& f) {
  33. 		v += f.v;
  34. 		return *this;
  35. 	}
  36.     float3& operator-= (const float3& f) {
  37. 		v -= f.v;
  38. 		return *this;
  39. 	}
  40. #else
  41. 	float3& operator+= (const float3& f) {
  42. 		x += f.x; y += f.y; z += f.z;
  43. 		return *this;
  44. 	}
  45.     float3& operator-= (const float3& f) {
  46. 		x -= f.x; y -= f.y; z -= f.z;
  47. 		return *this;
  48. 	}
  49. #endif
  50.  
  51.         inline float SqDistance(const float3& f) const {
  52.                 const float dx = x - f.x;
  53.                 const float dy = y - f.y;
  54.                 const float dz = z - f.z;
  55.                 return (dx*dx + dy*dy + dz*dz);
  56.         }
  57.  
  58. #ifdef USE_DOT
  59. 	bool equals(const float3& f) const {
  60. 		return this->SqDistance(f) <= CMP_EPS;
  61. 	}
  62. #elif defined(USE_SSE)
  63. 	bool equals(float3& f) {
  64. 		f3vector n;
  65. 		n.v = (v - f.v);
  66. 		n.v *= n.v;
  67. 		return (n.x + n.y + n.z) <= CMP_EPS;
  68. 	}
  69. #else
  70.         bool equals(const float3& f) const {
  71.                 return std::fabs(x - f.x) <= CMP_EPS
  72.                         && std::fabs(y - f.y) <= CMP_EPS
  73.                         && std::fabs(z - f.z) <= CMP_EPS;
  74.         }
  75. #endif
  76. };
  77.  
  78.  
  79. int main() {
  80.         int x = 0;
  81.         float3 a(0.1f,0.1f,0.1f);
  82. 	float3 b((float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX);
  83.         for (int i = 1<<25; i>0; --i) {
  84.                 if (a.equals(b)) {
  85.                         a += b;
  86.                         x++;
  87.                 }
  88.                 a.x += (float)rand()/(float)RAND_MAX;
  89.                 a.y += (float)rand()/(float)RAND_MAX;
  90.                 a.z += (float)rand()/(float)RAND_MAX;
  91.                 a -= b;
  92.         }
  93.         printf("%i\n", x);
  94.  
  95.         return 0;
  96. }
Success #stdin #stdout 2.69s 2724KB
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https://ideone.com/pfol5Z
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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