Mandlebrot set

[Doug Gwyn]

In article <1354 at uceng.UC.EDU> mfinegan at uceng.UC.EDU (michael k finegan) writes:
>    While the calculation of members of the Mandelbrot set may be well known, do
>you have pseudo-code for calculation of members of a Julia set?

There are all sorts of clever schemes, but the following extract from a
program that creates Mandelbrot & Julia convergence displays in the
"obvious" way shows that the calculations are quite similar:

	if ( julia )
		{
		zx = cx;
		zy = cy;
		for ( k = 0; k < iters; ++k )
			{
			register double	x = zx * zx - zy * zy + jx;

			zy = 2.0 * zx * zy + jy;
			zx = x;

			if ( zx * zx + zy * zy >= thresh )
				break;
			}
		}
	else	{	/* mandelbrot */
		zx = zy = 0.0;
		for ( k = 0; k < iters; ++k )
			{
			register double	x = zx * zx - zy * zy + cx;

			zy = 2.0 * zx * zy + cy;
			zx = x;

			if ( zx * zx + zy * zy >= thresh )
				break;
			}
		}