Mandelbrot Namespace Reference

Functions
template<typename T >
TEMPLATE_INLINE int32_t	mandelbrot_pixel (const T cx, const T cy, const int32_t max_iterations)
DEVICE double	get_scale (const double domain_min, const double domain_max, const int32_t num_bins)
template<typename T >
TEMPLATE_NOINLINE void	mandelbrot_impl (const int32_t x_pixels, const int32_t y_begin, const int32_t y_end, const T x_min, const T y_min, const T x_scale, const T y_scale, const int32_t max_iterations, Column< T > &output_x, Column< T > &output_y, Column< int32_t > &output_num_iterations)
template<typename T >
TEMPLATE_NOINLINE int32_t	mandelbrot_cpu_template (TableFunctionManager &mgr, const int32_t x_pixels, const int32_t y_pixels, const T x_min, const T x_max, const T y_min, const T y_max, const int32_t max_iterations, Column< T > &output_x, Column< T > &output_y, Column< int32_t > &output_num_iterations)

Function Documentation

DEVICE double Mandelbrot::get_scale ( const double  domain_min, const double  domain_max, const int32_t  num_bins  )

inline

Definition at line 63 of file ExampleTableFunctions.cpp.

Referenced by mandelbrot_cpu_template().

                                                       {
  return (domain_max - domain_min) / num_bins;
}

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template<typename T >

TEMPLATE_NOINLINE int32_t Mandelbrot::mandelbrot_cpu_template	(	TableFunctionManager &	mgr,
		const int32_t	x_pixels,
		const int32_t	y_pixels,
		const T	x_min,
		const T	x_max,
		const T	y_min,
		const T	y_max,
		const int32_t	max_iterations,
		Column< T > &	output_x,
		Column< T > &	output_y,
		Column< int32_t > &	output_num_iterations
	)

Definition at line 116 of file ExampleTableFunctions.cpp.

References get_scale(), mandelbrot_impl(), threading_serial::parallel_for(), TableFunctionManager::set_output_row_size(), and heavydb.dtypes::T.

                                                                    {

  const T x_scale = get_scale(x_min, x_max, x_pixels);
  const T y_scale = get_scale(y_min, y_max, y_pixels);

  const int32_t num_pixels = x_pixels * y_pixels;
  mgr.set_output_row_size(num_pixels);
#ifdef HAVE_TBB
  tbb::parallel_for(tbb::blocked_range<int32_t>(0, y_pixels),
                    [&](const tbb::blocked_range<int32_t>& y_itr) {
                      const int32_t y_begin = y_itr.begin();
                      const int32_t y_end = y_itr.end();
#else
  const int32_t y_begin = 0;
  const int32_t y_end = y_pixels;
#endif
                      mandelbrot_impl(x_pixels,
                                      y_begin,
                                      y_end,
                                      x_min,
                                      y_min,
                                      x_scale,
                                      y_scale,
                                      max_iterations,
                                      output_x,
                                      output_y,
                                      output_num_iterations);
#ifdef HAVE_TBB
                    });
#endif
  return num_pixels;
}

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template<typename T >

TEMPLATE_NOINLINE void Mandelbrot::mandelbrot_impl	(	const int32_t	x_pixels,
		const int32_t	y_begin,
		const int32_t	y_end,
		const T	x_min,
		const T	y_min,
		const T	x_scale,
		const T	y_scale,
		const int32_t	max_iterations,
		Column< T > &	output_x,
		Column< T > &	output_y,
		Column< int32_t > &	output_num_iterations
	)

Definition at line 77 of file ExampleTableFunctions.cpp.

References mandelbrot_pixel(), and heavydb.dtypes::T.

Referenced by mandelbrot_cpu_template().

                                                            {
  // scanning every point in that rectangular area.
  // each point represents a complex number (x + yi).
  // iterate that complex number

  for (int32_t y = y_begin; y < y_end; ++y) {
    // c_imaginary
    const T cy = y * y_scale + y_min;
    for (int32_t x = 0; x < x_pixels; ++x) {
      // c_real
      const T cx = x * x_scale + x_min;
      const int32_t output_pixel = y * x_pixels + x;
      output_x[output_pixel] = cx;
      output_y[output_pixel] = cy;
      output_num_iterations[output_pixel] = mandelbrot_pixel(cx, cy, max_iterations);
    }
  }
}

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template<typename T >

TEMPLATE_INLINE int32_t Mandelbrot::mandelbrot_pixel	(	const T	cx,
		const T	cy,
		const int32_t	max_iterations
	)

Definition at line 33 of file ExampleTableFunctions.cpp.

References heavydb.dtypes::T.

Referenced by mandelbrot_impl().

                                                                       {
  // z_real
  T zx = 0;
  // z_imaginary
  T zy = 0;
  int32_t num_iterations = 0;
  // Calculate whether c(c_real + c_imaginary) belongs
  // to the Mandelbrot set or not and draw a pixel
  // at coordinates (x, y) accordingly
  // If you reach the Maximum number of iterations
  // and If the distance from the origin is
  // greater terthan 2 exit the loop
  while ((zx * zx + zy * zy < 4) && (num_iterations < max_iterations)) {
    // Calculate Mandelbrot function
    // z = z*z + c where z is a complex number
    // tempx = z_real*_real - z_imaginary*z_imaginary + c_real
    const T temp_x = zx * zx - zy * zy + cx;
    // 2*z_real*z_imaginary + c_imaginary
    zy = 2 * zx * zy + cy;
    // Updating z_real = tempx
    zx = temp_x;

    // Increment counter
    ++num_iterations;
  }
  return num_iterations;
}

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