08 - DEM example with perturbation

This example shows how to create a color layer, displaying the distance estimation for Mandelbrot (power 2) fractal.

The location, at 16.e-22, is below the reach of double, pertubation theory must be used.

Reference: fractalshades.models.Perturbation_mandelbrot

import os

import fractalshades as fs
import fractalshades.models as fsm
import fractalshades.settings as settings
import fractalshades.colors as fscolors


from fractalshades.postproc import (
    Postproc_batch,
    DEM_pp,
    Continuous_iter_pp,
    Raw_pp,
    DEM_normal_pp,
    # Fieldlines_pp,
)
from fractalshades.colors.layers import (
    Color_layer,
    Bool_layer,
    # Blinn_lighting,
    # Normal_map_layer,
    Virtual_layer,
)

def plot(directory):
    """
    Example plot of distance estimation method
    """
    settings.enable_multithreading = True

    # A simple showcas using perturbation technique
    x = "-1.768667862837488812627419470"
    y = "0.001645580546820209430325900"
    dx = "16.e-22"
    precision = 30
    nx = 2400

    colormap = fscolors.cmap_register["autumn"]

    f = fsm.Perturbation_mandelbrot(directory)
    f.zoom(precision=precision,
            x=x,
            y=y,
            dx=dx,
            nx=nx,
            xy_ratio=1.0,
            theta_deg=0.,
            projection=fs.projection.Cartesian()
    )

    f.calc_std_div(
            calc_name="div",
            subset=None,
            max_iter=50000, #00,
            M_divergence=1.e3,
            epsilon_stationnary=1.e-3,
            BLA_eps=1.e-6,
            interior_detect=True,
    )

    # Plot the image
    pp = Postproc_batch(f, "div")
    pp.add_postproc("potential", Continuous_iter_pp())
    pp.add_postproc("DEM", DEM_pp())
    pp.add_postproc("interior", Raw_pp("stop_reason", func="x != 1."))
    pp.add_postproc("DEM_map", DEM_normal_pp(kind="potential"))

    plotter = fs.Fractal_plotter(pp)
    plotter.add_layer(Bool_layer("interior", output=False))
    plotter.add_layer(Virtual_layer("potential", func=None, output=False))
    plotter.add_layer(Color_layer(
            "DEM",
            func="x",
            colormap=colormap,
            probes_z=[0.01061, 0.03184],
            output=True
    ))
    plotter["DEM"].set_mask(
            plotter["interior"],
            mask_color=(0., 0., 0.)
    )

    plotter.plot()

if __name__ == "__main__":
    # Some magic to get the directory for plotting: with a name that matches
    # the file or a temporary dir if we are building the documentation
    try:
        realpath = os.path.realpath(__file__)
        plot_dir = os.path.splitext(realpath)[0]
        plot(plot_dir)
    except NameError:
        import tempfile
        with tempfile.TemporaryDirectory() as plot_dir:
            fs.utils.exec_no_output(plot, plot_dir)