multithreaded mandelbrot set - python
Is it possible to change the formula of the mandelbrot set (which is f(z) = z^2 + c by default) to a different one ( f(z) = z^2 + c * e^(-z) is what i need) when using the escape time algorithm and if possible how?
I'm currently using this code by FB36
# Multi-threaded Mandelbrot Fractal (Do not run using IDLE!)
# FB - 201104306
import threading
from PIL import Image
w = 512 # image width
h = 512 # image height
image = Image.new("RGB", (w, h))
wh = w * h
maxIt = 256 # max number of iterations allowed
# drawing region (xa < xb & ya < yb)
xa = -2.0
xb = 1.0
ya = -1.5
yb = 1.5
xd = xb - xa
yd = yb - ya
numThr = 5 # number of threads to run
# lock = threading.Lock()
class ManFrThread(threading.Thread):
def __init__ (self, k):
self.k = k
threading.Thread.__init__(self)
def run(self):
# each thread only calculates its own share of pixels
for i in range(k, wh, numThr):
kx = i % w
ky = int(i / w)
a = xa + xd * kx / (w - 1.0)
b = ya + yd * ky / (h - 1.0)
x = a
y = b
for kc in range(maxIt):
x0 = x * x - y * y + a
y = 2.0 * x * y + b
x = x0
if x * x + y * y > 4:
# various color palettes can be created here
red = (kc % 8) * 32
green = (16 - kc % 16) * 16
blue = (kc % 16) * 16
# lock.acquire()
global image
image.putpixel((kx, ky), (red, green, blue))
# lock.release()
break
if __name__ == "__main__":
tArr = []
for k in range(numThr): # create all threads
tArr.append(ManFrThread(k))
for k in range(numThr): # start all threads
tArr[k].start()
for k in range(numThr): # wait until all threads finished
tArr[k].join()
image.save("MandelbrotFractal.png", "PNG")
From the code I infer that z = x + y * i and c = a + b * i. That corresponds f(z) - z ^2 + c. You want f(z) = z ^2 + c * e^(-z).
Recall that e^(-z) = e^-(x + yi) = e^(-x) * e^i(-y) = e^(-x)(cos(y) - i*sin(y)) = e^(-x)cos(y) - i (e^(-x)sin(y)). Thus you should update your lines to be the following:
x0 = x * x - y * y + a * exp(-x) * cos(y) + b * exp(-x) * sin(y);
y = 2.0 * x * y + a * exp(-x) * sin(y) - b * exp(-x) * cos(y)
x = x0
You might need to adjust maxIt if you don't get the level of feature differentiation you're after (it might take more or fewer iterations to escape now, on average) but this should be the mathematical expression you're after.
As pointed out in the comments, you might need to adjust the criterion itself and not just the maximum iterations in order to get the desired level of differentiation: changing the max doesn't help for ones that never escape.
You can try deriving a good escape condition or just try out some things and see what you get.
Related
Python: maldelbrot set multithreaded
I'm using the following algorithm to generate a Mandelbrot set fractal using threads in Python. Something is not working properly because I got minimum difference in time processing using 2, 4 , 8 or even 10 threads. Can someone kinldy help me and take a look to the code so it work correctly, please?! import threading from PIL import Image import matplotlib.pyplot as plt from timeit import default_timer as timer # Fractals are infinitely repeating patterns on different scales xSize = ySize = 2096 # defines a finite number of pixels on axes x and y. image = Image.new("RGB", (xSize, ySize)) imageSize = xSize * ySize maxIt = 256 # defines the maximun number of interactions allowed # drawing region (xa < xb & ya < yb): defined the domain plan xa = -2.0 # defines the begin of the real axis X: from xa xb = 0.5 # defines the end of the real axis X: to xb ya = -1.25 # defines the begin of the imaginary axis Y: from ya yb = 1.25 # defines the end of the imaginary axis Y: to yb xd = xb - xa # defines x dimension yd = yb - ya # defines y dimension numThr = 4 # number of threads to run class MandelbrotThread(threading.Thread): print('Generating fractal image of size {0} x {1} with {2} interactions using {3} threads'.format(xSize, ySize, maxIt, numThr)) def __init__ (self, k): self.k = k threading.Thread.__init__(self) print("Executing thread ", k) def run(self): # each thread only calculates its own share of pixels on the domain plan for i in range(t, imageSize, numThr): kx = i % xSize #calculates module to define pixels width ky = int(i / xSize) #calculates module to define pixels height xvalue = xa + xd * kx / (xSize - 1.0) # for every row: associates values to the axis x yvalue = ya + yd * ky / (ySize - 1.0) # for every col: associates values to the axis Y nReal = xvalue nImag = yvalue for n in range(maxIt): nReal2 = nReal * nReal nImag2 = nImag * nImag nImag = 2.0 * nReal * nImag + yvalue nReal = nReal2 - nImag2 + xvalue if nReal2 + nImag2 > 4: # various color palettes can be created here red = (n % 8) * 32 green = (20 - n % 20) * 20 blue = (n % 15) * 15 image.putpixel((kx, ky), (red, green, blue)) break if __name__ == "__main__": tArr = [] for t in range(numThr): # create all threads tArr.append(MandelbrotThread(t)) start = timer() for t in range(numThr): # start all threads tArr[t].start() for t in range(numThr): # wait until all threads finished tArr[t].join() duration = timer() - start print(f'Total processing time: {duration:.2f} seconds') image.show()
How to increase FPS in ursina python
I want to create survival games with infinite block terrain(like Minecraft). So i using ursina python game engine, you can see it here So i using perlin noise to create the terrain with build-in ursina block model. I test for first 25 block and it work pretty good with above 100 FPS, so i start increase to 250 block and more because I want a infinite terrain. But i ran to some problem, when i increase to 100 block or more, my FPS start to decrease below 30 FPS (With i create just one layer). Here is my code: #-------------------------------Noise.py(I got on the github)------------------------- # Copyright (c) 2008, Casey Duncan (casey dot duncan at gmail dot com) # see LICENSE.txt for details """Perlin noise -- pure python implementation""" __version__ = '$Id: perlin.py 521 2008-12-15 03:03:52Z casey.duncan $' from math import floor, fmod, sqrt from random import randint # 3D Gradient vectors _GRAD3 = ((1,1,0),(-1,1,0),(1,-1,0),(-1,-1,0), (1,0,1),(-1,0,1),(1,0,-1),(-1,0,-1), (0,1,1),(0,-1,1),(0,1,-1),(0,-1,-1), (1,1,0),(0,-1,1),(-1,1,0),(0,-1,-1), ) # 4D Gradient vectors _GRAD4 = ((0,1,1,1), (0,1,1,-1), (0,1,-1,1), (0,1,-1,-1), (0,-1,1,1), (0,-1,1,-1), (0,-1,-1,1), (0,-1,-1,-1), (1,0,1,1), (1,0,1,-1), (1,0,-1,1), (1,0,-1,-1), (-1,0,1,1), (-1,0,1,-1), (-1,0,-1,1), (-1,0,-1,-1), (1,1,0,1), (1,1,0,-1), (1,-1,0,1), (1,-1,0,-1), (-1,1,0,1), (-1,1,0,-1), (-1,-1,0,1), (-1,-1,0,-1), (1,1,1,0), (1,1,-1,0), (1,-1,1,0), (1,-1,-1,0), (-1,1,1,0), (-1,1,-1,0), (-1,-1,1,0), (-1,-1,-1,0)) # A lookup table to traverse the simplex around a given point in 4D. # Details can be found where this table is used, in the 4D noise method. _SIMPLEX = ( (0,1,2,3),(0,1,3,2),(0,0,0,0),(0,2,3,1),(0,0,0,0),(0,0,0,0),(0,0,0,0),(1,2,3,0), (0,2,1,3),(0,0,0,0),(0,3,1,2),(0,3,2,1),(0,0,0,0),(0,0,0,0),(0,0,0,0),(1,3,2,0), (0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0), (1,2,0,3),(0,0,0,0),(1,3,0,2),(0,0,0,0),(0,0,0,0),(0,0,0,0),(2,3,0,1),(2,3,1,0), (1,0,2,3),(1,0,3,2),(0,0,0,0),(0,0,0,0),(0,0,0,0),(2,0,3,1),(0,0,0,0),(2,1,3,0), (0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0), (2,0,1,3),(0,0,0,0),(0,0,0,0),(0,0,0,0),(3,0,1,2),(3,0,2,1),(0,0,0,0),(3,1,2,0), (2,1,0,3),(0,0,0,0),(0,0,0,0),(0,0,0,0),(3,1,0,2),(0,0,0,0),(3,2,0,1),(3,2,1,0)) # Simplex skew constants _F2 = 0.5 * (sqrt(3.0) - 1.0) _G2 = (3.0 - sqrt(3.0)) / 6.0 _F3 = 1.0 / 3.0 _G3 = 1.0 / 6.0 class BaseNoise: """Noise abstract base class""" permutation = (151,160,137,91,90,15, 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190,6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88,237,149,56,87,174,20,125,136,171,168,68,175,74,165,71,134,139,48,27,166, 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102,143,54,65,25,63,161,1,216,80,73,209,76,132,187,208,89,18,169,200,196, 135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,250,124,123, 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223,183,170,213,119,248,152,2,44,154,163,70,221,153,101,155,167,43,172,9, 129,22,39,253,9,98,108,110,79,113,224,232,178,185,112,104,218,246,97,228, 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49,192,214,31,181,199,106,157,184,84,204,176,115,121,50,45,127,4,150,254, 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180) period = len(permutation) # Double permutation array so we don't need to wrap permutation = permutation * 2 randint_function = randint def __init__(self, period=None, permutation_table=None, randint_function=None): """Initialize the noise generator. With no arguments, the default period and permutation table are used (256). The default permutation table generates the exact same noise pattern each time. An integer period can be specified, to generate a random permutation table with period elements. The period determines the (integer) interval that the noise repeats, which is useful for creating tiled textures. period should be a power-of-two, though this is not enforced. Note that the speed of the noise algorithm is indpendent of the period size, though larger periods mean a larger table, which consume more memory. A permutation table consisting of an iterable sequence of whole numbers can be specified directly. This should have a power-of-two length. Typical permutation tables are a sequnce of unique integers in the range [0,period) in random order, though other arrangements could prove useful, they will not be "pure" simplex noise. The largest element in the sequence must be no larger than period-1. period and permutation_table may not be specified together. A substitute for the method random.randint(a, b) can be chosen. The method must take two integer parameters a and b and return an integer N such that a <= N <= b. """ if randint_function is not None: # do this before calling randomize() if not hasattr(randint_function, '__call__'): raise TypeError( 'randint_function has to be a function') self.randint_function = randint_function if period is None: period = self.period # enforce actually calling randomize() if period is not None and permutation_table is not None: raise ValueError( 'Can specify either period or permutation_table, not both') if period is not None: self.randomize(period) elif permutation_table is not None: self.permutation = tuple(permutation_table) * 2 self.period = len(permutation_table) def randomize(self, period=None): """Randomize the permutation table used by the noise functions. This makes them generate a different noise pattern for the same inputs. """ if period is not None: self.period = period perm = list(range(self.period)) perm_right = self.period - 1 for i in list(perm): j = self.randint_function(0, perm_right) perm[i], perm[j] = perm[j], perm[i] self.permutation = tuple(perm) * 2 class SimplexNoise(BaseNoise): """Perlin simplex noise generator Adapted from Stefan Gustavson's Java implementation described here: http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf To summarize: "In 2001, Ken Perlin presented 'simplex noise', a replacement for his classic noise algorithm. Classic 'Perlin noise' won him an academy award and has become an ubiquitous procedural primitive for computer graphics over the years, but in hindsight it has quite a few limitations. Ken Perlin himself designed simplex noise specifically to overcome those limitations, and he spent a lot of good thinking on it. Therefore, it is a better idea than his original algorithm. A few of the more prominent advantages are: * Simplex noise has a lower computational complexity and requires fewer multiplications. * Simplex noise scales to higher dimensions (4D, 5D and up) with much less computational cost, the complexity is O(N) for N dimensions instead of the O(2^N) of classic Noise. * Simplex noise has no noticeable directional artifacts. Simplex noise has a well-defined and continuous gradient everywhere that can be computed quite cheaply. * Simplex noise is easy to implement in hardware." """ def noise2(self, x, y): """2D Perlin simplex noise. Return a floating point value from -1 to 1 for the given x, y coordinate. The same value is always returned for a given x, y pair unless the permutation table changes (see randomize above). """ # Skew input space to determine which simplex (triangle) we are in s = (x + y) * _F2 i = floor(x + s) j = floor(y + s) t = (i + j) * _G2 x0 = x - (i - t) # "Unskewed" distances from cell origin y0 = y - (j - t) if x0 > y0: i1 = 1; j1 = 0 # Lower triangle, XY order: (0,0)->(1,0)->(1,1) else: i1 = 0; j1 = 1 # Upper triangle, YX order: (0,0)->(0,1)->(1,1) x1 = x0 - i1 + _G2 # Offsets for middle corner in (x,y) unskewed coords y1 = y0 - j1 + _G2 x2 = x0 + _G2 * 2.0 - 1.0 # Offsets for last corner in (x,y) unskewed coords y2 = y0 + _G2 * 2.0 - 1.0 # Determine hashed gradient indices of the three simplex corners perm = self.permutation ii = int(i) % self.period jj = int(j) % self.period gi0 = perm[ii + perm[jj]] % 12 gi1 = perm[ii + i1 + perm[jj + j1]] % 12 gi2 = perm[ii + 1 + perm[jj + 1]] % 12 # Calculate the contribution from the three corners tt = 0.5 - x0**2 - y0**2 if tt > 0: g = _GRAD3[gi0] noise = tt**4 * (g[0] * x0 + g[1] * y0) else: noise = 0.0 tt = 0.5 - x1**2 - y1**2 if tt > 0: g = _GRAD3[gi1] noise += tt**4 * (g[0] * x1 + g[1] * y1) tt = 0.5 - x2**2 - y2**2 if tt > 0: g = _GRAD3[gi2] noise += tt**4 * (g[0] * x2 + g[1] * y2) return noise * 70.0 # scale noise to [-1, 1] def noise3(self, x, y, z): """3D Perlin simplex noise. Return a floating point value from -1 to 1 for the given x, y, z coordinate. The same value is always returned for a given x, y, z pair unless the permutation table changes (see randomize above). """ # Skew the input space to determine which simplex cell we're in s = (x + y + z) * _F3 i = floor(x + s) j = floor(y + s) k = floor(z + s) t = (i + j + k) * _G3 x0 = x - (i - t) # "Unskewed" distances from cell origin y0 = y - (j - t) z0 = z - (k - t) # For the 3D case, the simplex shape is a slightly irregular tetrahedron. # Determine which simplex we are in. if x0 >= y0: if y0 >= z0: i1 = 1; j1 = 0; k1 = 0 i2 = 1; j2 = 1; k2 = 0 elif x0 >= z0: i1 = 1; j1 = 0; k1 = 0 i2 = 1; j2 = 0; k2 = 1 else: i1 = 0; j1 = 0; k1 = 1 i2 = 1; j2 = 0; k2 = 1 else: # x0 < y0 if y0 < z0: i1 = 0; j1 = 0; k1 = 1 i2 = 0; j2 = 1; k2 = 1 elif x0 < z0: i1 = 0; j1 = 1; k1 = 0 i2 = 0; j2 = 1; k2 = 1 else: i1 = 0; j1 = 1; k1 = 0 i2 = 1; j2 = 1; k2 = 0 # Offsets for remaining corners x1 = x0 - i1 + _G3 y1 = y0 - j1 + _G3 z1 = z0 - k1 + _G3 x2 = x0 - i2 + 2.0 * _G3 y2 = y0 - j2 + 2.0 * _G3 z2 = z0 - k2 + 2.0 * _G3 x3 = x0 - 1.0 + 3.0 * _G3 y3 = y0 - 1.0 + 3.0 * _G3 z3 = z0 - 1.0 + 3.0 * _G3 # Calculate the hashed gradient indices of the four simplex corners perm = self.permutation ii = int(i) % self.period jj = int(j) % self.period kk = int(k) % self.period gi0 = perm[ii + perm[jj + perm[kk]]] % 12 gi1 = perm[ii + i1 + perm[jj + j1 + perm[kk + k1]]] % 12 gi2 = perm[ii + i2 + perm[jj + j2 + perm[kk + k2]]] % 12 gi3 = perm[ii + 1 + perm[jj + 1 + perm[kk + 1]]] % 12 # Calculate the contribution from the four corners noise = 0.0 tt = 0.6 - x0**2 - y0**2 - z0**2 if tt > 0: g = _GRAD3[gi0] noise = tt**4 * (g[0] * x0 + g[1] * y0 + g[2] * z0) else: noise = 0.0 tt = 0.6 - x1**2 - y1**2 - z1**2 if tt > 0: g = _GRAD3[gi1] noise += tt**4 * (g[0] * x1 + g[1] * y1 + g[2] * z1) tt = 0.6 - x2**2 - y2**2 - z2**2 if tt > 0: g = _GRAD3[gi2] noise += tt**4 * (g[0] * x2 + g[1] * y2 + g[2] * z2) tt = 0.6 - x3**2 - y3**2 - z3**2 if tt > 0: g = _GRAD3[gi3] noise += tt**4 * (g[0] * x3 + g[1] * y3 + g[2] * z3) return noise * 32.0 def lerp(t, a, b): return a + t * (b - a) def grad3(hash, x, y, z): g = _GRAD3[hash % 16] return x*g[0] + y*g[1] + z*g[2] class TileableNoise(BaseNoise): """Tileable implemention of Perlin "improved" noise. This is based on the reference implementation published here: http://mrl.nyu.edu/~perlin/noise/ """ def noise3(self, x, y, z, repeat, base=0.0): """Tileable 3D noise. repeat specifies the integer interval in each dimension when the noise pattern repeats. base allows a different texture to be generated for the same repeat interval. """ i = int(fmod(floor(x), repeat)) j = int(fmod(floor(y), repeat)) k = int(fmod(floor(z), repeat)) ii = (i + 1) % repeat jj = (j + 1) % repeat kk = (k + 1) % repeat if base: i += base; j += base; k += base ii += base; jj += base; kk += base x -= floor(x); y -= floor(y); z -= floor(z) fx = x**3 * (x * (x * 6 - 15) + 10) fy = y**3 * (y * (y * 6 - 15) + 10) fz = z**3 * (z * (z * 6 - 15) + 10) perm = self.permutation A = perm[i] AA = perm[A + j] AB = perm[A + jj] B = perm[ii] BA = perm[B + j] BB = perm[B + jj] return lerp(fz, lerp(fy, lerp(fx, grad3(perm[AA + k], x, y, z), grad3(perm[BA + k], x - 1, y, z)), lerp(fx, grad3(perm[AB + k], x, y - 1, z), grad3(perm[BB + k], x - 1, y - 1, z))), lerp(fy, lerp(fx, grad3(perm[AA + kk], x, y, z - 1), grad3(perm[BA + kk], x - 1, y, z - 1)), lerp(fx, grad3(perm[AB + kk], x, y - 1, z - 1), grad3(perm[BB + kk], x - 1, y - 1, z - 1)))) #--------------------------Math.py(For InverseLefp)-------------------------------- def Clamp(t: float, minimum: float, maximum: float): """Float result between a min and max values.""" value = t if t < minimum: value = minimum elif t > maximum: value = maximum return value def InverseLefp(a: float, b: float, value: float): if a != b: return Clamp((value - a) / (b - a), 0, 1) return 0 #-----------------------------Game.py(Main code)---------------------- from ursina import * from ursina.prefabs import * from ursina.prefabs.first_person_controller import * from Math import InverseLefp import Noise app = Ursina() #The maximum height of the terrain maxHeight = 10 #Control the width and height of the map mapWidth = 10 mapHeight = 10 #A class that create a block class Voxel(Button): def __init__(self, position=(0,0,0)): super().__init__( parent = scene, position = position, model = 'cube', origin_y = .5, texture = 'white_cube', color = color.color(0, 0, random.uniform(.9, 1.0)), highlight_color = color.lime, ) #Detect user key input def input(self, key): if self.hovered: if key == 'right mouse down': #Place block if user right click voxel = Voxel(position=self.position + mouse.normal) if key == 'left mouse down': #Break block if user left click destroy(self) if key == 'escape': #Exit the game if user press the esc key app.userExit() #Return perlin noise value between 0 and 1 with x, y position with scale = noiseScale def GeneratedNoiseMap(y: int, x: int, noiseScale: float): #Check if the noise scale was invalid or not if noiseScale <= 0: noiseScale = 0.001 sampleX = x / noiseScale sampleY = y / noiseScale #The Noise.SimplexNoise().noise2 will return the value between -1 and 1 perlinValue = Noise.SimplexNoise().noise2(sampleX, sampleY) #The InverseLefp will make the value scale to between 0 and 1 perlinValue = InverseLefp(-1, 1, perlinValue) return perlinValue for z in range(mapHeight): for x in range(mapWidth): #Calculating the height of the block and round it to integer height = round(GeneratedNoiseMap(z, x, 20) * maxHeight) #Place the block and make it always below the player block = Voxel(position=(x, height - maxHeight - 1, z)) #Set the collider of the block block.collider = 'mesh' #Character movement player = FirstPersonController() #Run the game app.run() All file in same folder. It was working fine but the FPS is very low, so can anyone help?
I'm not able to test this code at the moment but this should serve as a starting point: level_parent = Entity(model=Mesh(vertices=[], uvs=[])) for z in range(mapHeight): for x in range(mapWidth): height = round(GeneratedNoiseMap(z, x, 20) * maxHeight) block = Voxel(position=(x, height - maxHeight - 1, z)) level_parent.model.vertices.extend(block.model.vertices) level_parent.collider = 'mesh' # call this only once after all vertices are set up For texturing, you might have to add the block.uvs from each block to level_parent.model.uvs as well. Alternatively, call level_parent.model.project_uvs() after setting up the vertices.
On my version of ursina engine (5.0.0) only this code: ` level_parent = Entity(model=Mesh(vertices=[], uvs=[])) for z in range(mapHeight): for x in range(mapWidth): height = round(GeneratedNoiseMap(z, x, 20) * maxHeight) block = Voxel(position=(x, height - maxHeight - 1, z)) #level_parent.model.vertices.extend(block.model.vertices) level_parent.combine().vertices.extend(block.combine().vertices) level_parent.collider = 'mesh' ` is working.
I want to have the pendulum blob in my double pendulum
In this code I want to have animation something like this. But I dont want the other pendulums that come into picture later. Just the initial one. Currently this is my output. This is the image after the animation completes. In the animation, I want to have a ball(blob) which plots the red lines and another one which plots the green lines. import numpy as np from numpy import cos, sin, arange, pi import matplotlib.pyplot as plt import matplotlib.animation as animation h = 0.0002 #the change in runge kutta figsize = 6 dpi = 1000 N = 200000 # iterations L1=1 #length 1 L2=1.5 #lenth 2 m1=50 #mass of bob 1 m2=1 #mass of bob2 g = 9.81#gravity theta_01 = (np.pi/180)*90 theta_02 = (np.pi/180)*60 w_1 = 0 w_2 = 0 # dw/dt function oft theta 1 def funcdwdt1(theta1,theta2,w1,w2): cos12 = cos(theta1 - theta2)#for wrirting the main equation in less complex manner sin12 = sin(theta1 - theta2) sin1 = sin(theta1) sin2 = sin(theta2) denom = cos12**2*m2 - m1 - m2 ans = ( L1*m2*cos12*sin12*w1**2 + L2*m2*sin12*w2**2 - m2*g*cos12*sin2 + (m1 + m2)*g*sin1)/(L1*denom) return ans # dw/dt function oft thetas 2 def funcdwdt2(theta2,theta1,w1,w2): cos12 = cos(theta1 - theta2) sin12 = sin(theta1 - theta2) sin1 = sin(theta1) sin2 = sin(theta2) denom = cos12**2*m2 - m1 - m2 ans2 = -( L2*m2*cos12*sin12*w2**2 + L1*(m1 + m2)*sin12*w1**2 + (m1 + m2)*g*sin1*cos12 - (m1 + m2)*g*sin2 )/(L2*denom) return ans2 # d0/dt function for theta 1 def funcd0dt1(w0): return w0 # d0/dt function for theta 2 def funcd0dt2(w0): return w0 X1= [] X2= [] Y1= [] Y2= [] def func(w1,w2, theta1,theta2): for i in range(N): k1a = h * funcd0dt1(w1) # gives theta1 k1b = h * funcdwdt1(theta1,theta2,w1,w2) # gives omega1 k1c = h * funcd0dt2(w2) # gives theta2 k1d = h * funcdwdt2(theta2,theta1,w1,w2) # gives omega2 k2a = h * funcd0dt1(w1 + (0.5 * k1b)) k2b = h * funcdwdt1(theta1 + (0.5 * k1a),theta2,w1,w2) k2c = h * funcd0dt2(w2 + (0.5 * k1d)) k2d = h * funcdwdt2(theta2 + (0.5 * k1c),theta1,w1,w2) k3a = h * funcd0dt1(w1 + (0.5 * k2b)) k3b = h * funcdwdt1(theta1 + (0.5 * k2a),theta2,w1,w2) k3c = h * funcd0dt2(w2 + (0.5 * k2d)) k3d = h * funcdwdt2(theta2 + (0.5 * k2c),theta1,w1,w2) k4a = h * funcd0dt1(w1 + k3b) k4b = h * funcdwdt1(theta1 + k3a,theta2,w1,w2) k4c = h * funcd0dt2(w2 + k3d) k4d = h * funcdwdt2(theta2 + k3c,theta1,w1,w2) #addidng the vakue aftyer the iterartions theta1 += 1 / 6 * (k1a + 2 * k2a + 2 * k3a + k4a) w1 +=1 / 6 * (k1b + 2 * k2b + 2 * k3b + k4b) theta2 += + 1 / 6 * (k1c + 2 * k2c + 2 * k3c + k4c) w2 += 1 / 6 * (k1d + 2 * k2d + 2 * k3d + k4d) x1 = L1 * sin(theta1) y1 = -L1 * cos(theta1) x2 = x1 + L2 * sin(theta2) y2 = y1 - L2 * cos(theta2) X1.append(x1) X2.append(x2) Y1.append(y1) Y2.append(y2) return x1,y1,x2,y2 print(func(w_1, w_2, theta_01, theta_02)) fig, ax = plt.subplots() l1, = ax.plot([], []) l2, = ax.plot([],[]) ax.set(xlim=(-3, 3), ylim=(-2,2)) def animate(i): l1.set_data(X1[:i], Y2[:i]) l2.set_data(X2[:i], Y2[:i]) return l1,l2, ani = animation.FuncAnimation(fig, animate, interval = 5, frames=len(X1)) # plt.show() ani.save('save.mp4', writer='ffmpeg')
Just add another line l3, = ax.plot([],[], '-ob', lw=2, ms=8) and in the animate function set its values to l3.set_data([0,X1[i],X2[i]], [0,Y1[i],Y2[i]]) Adapt line-width and marker-size as necessary. This should draw filled circles at the pendulum positions and the origin with lines connecting them. You should use Y1 in the l1 data. With a total pendulum length of 2.5, the vertical limits are too small. It is sufficient to use h = 0.005 #the change in runge kutta N = 5000 # iterations to get an animation with realistic speed. Or combine several RK4 steps for each frame. For minimum error you can use h=1e-3, smaller step sizes only lead to the accumulation of floating point errors dominating the method error.
Smooth coloring\Normalized Iteration with Julia set - Python
I've been working on making a julia set code with python. I didn't write the original code, but I modified it slightly and it achieves what I want it too... except smooth coloring! I've read on how to do it, but I'm still confused. Code pre-color-smoothing attempt: def julia(): while True: try: julwidth = int(input("What width would you like the image? ex. 256, 512, etc. \nLarger numbers take longer to compute.\n")) julheight = int(input("What height would you like the image? ex. 256, 512, etc. \nLarger numbers take longer to compute.\n")) iter = int(input("Max iterations? If you don't know, 255 is a good number \n")) break except ValueError: print("Enter an integer, please") print("Running Julia fractal... please wait...") imgx = julwidth imgy = julheight image = Image.new("RGB", (imgx, imgy)) # drawing area xa = -2.0 xb = 2.0 ya = -1.5 yb = 1.5 maxIt = iter # max iterations allowed Time = time.clock() #print(time) # find a good Julia set point using the Mandelbrot set while True: cx = random.random() * (xb - xa) + xa cy = random.random() * (yb - ya) + ya c = cx + cy * 1j z = c for i in range(maxIt): if abs(z) > 2.0: break z = z * z + c if i > 10 and i < 100: break # draw the Julia set for y in range(imgy): zy = y * (yb - ya) / (imgy - 1) + ya for x in range(imgx): zx = x * (xb - xa) / (imgx - 1) + xa z = zx + zy * 1j for i in range(maxIt): if abs(z) > 2.0: break z = z * z + c red = i % 8 *32 green = i % 16 * 16 blue = i % 32 * 8 #print(red, green, blue) image.putpixel((x, y), (red, green, blue)) print("Done computing. \n") With smoothing attempt: def julia(): while True: try: julwidth = int(input("What width would you like the image? ex. 256, 512, etc. \nLarger numbers take longer to compute.\n")) julheight = int(input("What height would you like the image? ex. 256, 512, etc. \nLarger numbers take longer to compute.\n")) iter = int(input("Max iterations? If you don't know, 255 is a good number \n")) break except ValueError: print("Enter an integer, please") print("Running Julia fractal... please wait...") imgx = julwidth imgy = julheight image = Image.new("RGB", (imgx, imgy)) # drawing area xa = -2.0 xb = 2.0 ya = -1.5 yb = 1.5 maxIt = iter # max iterations allowed Time = time.clock() #print(time) # find a good Julia set point using the Mandelbrot set while True: cx = random.random() * (xb - xa) + xa cy = random.random() * (yb - ya) + ya c = cx + cy * 1j z = c for i in range(maxIt): if abs(z) > 2.0: break z = z * z + c smooth = (abs(z)) if i > 10 and i < 100: break # draw the Julia set for y in range(imgy): zy = y * (yb - ya) / (imgy - 1) + ya for x in range(imgx): zx = x * (xb - xa) / (imgx - 1) + xa z = zx + zy * 1j for i in range(maxIt): if abs(z) > 2.0: break z = z * z + c smooth += (abs(z)) #print(smooth) red = ceil(smooth % 8 * 32) green = ceil(red*red) blue = ceil(green*red) #print(red, green, blue) image.putpixel((x, y), (red, green, blue)) print("Done computing. \n") If you can't tell, I added a variable called smooth that I'm using to try and smooth the colors with by using the complex number/variable, z Running my code with the smoothing attempt yields something..... not what I want. It's a weird blue image and it's not good. How can I add smoothing to this? I probably don't have a good understanding of smoothing, so an explanation might help.
Compute fractional escape counts and set the color according to that: ec = N + 1 - log (log |Z(N)|) / log 2 where N is the escape count when the value of 'z' escaped, Z(N) is the value of zwhen it escaped and |z| is the modulus of z which is just sqrt (x*x + y*y).
Simplex Noise Function: Unexpected Results
I'm trying to adapt this noise module to a project I'm working on but I'm not getting the results I was expecting: https://pypi.python.org/pypi/noise/ Instead of a varied height-map, each row tends to have the exact same value. If I create something 250x250 it will generate the same value 250 times and then generate a new value 250 times until it ends. Here is the function I'm currently using. I understand this function fairly well but I'm just not sure how to get more "interesting" results. Thank you for your help. class SimplexNoise(BaseNoise): def noise2(self, x, y): """2D Perlin simplex noise. Return a floating point value from -1 to 1 for the given x, y coordinate. The same value is always returned for a given x, y pair unless the permutation table changes (see randomize above). """ # Skew input space to determine which simplex (triangle) we are in s = (x + y) * _F2 i = floor(x + s) j = floor(y + s) t = (i + j) * _G2 x0 = x - (i - t) # "Unskewed" distances from cell origin y0 = y - (j - t) if x0 > y0: i1 = 1; j1 = 0 # Lower triangle, XY order: (0,0)->(1,0)->(1,1) else: i1 = 0; j1 = 1 # Upper triangle, YX order: (0,0)->(0,1)->(1,1) x1 = x0 - i1 + _G2 # Offsets for middle corner in (x,y) unskewed coords y1 = y0 - j1 + _G2 x2 = x0 + _G2 * 2.0 - 1.0 # Offsets for last corner in (x,y) unskewed coords y2 = y0 + _G2 * 2.0 - 1.0 # Determine hashed gradient indices of the three simplex corners perm = BaseNoise.permutation ii = int(i) % BaseNoise.period jj = int(j) % BaseNoise.period gi0 = perm[ii + perm[jj]] % 12 gi1 = perm[ii + i1 + perm[jj + j1]] % 12 gi2 = perm[ii + 1 + perm[jj + 1]] % 12 # Calculate the contribution from the three corners tt = 0.5 - x0**2 - y0**2 if tt > 0: g = _GRAD3[gi0] noise = tt**4 * (g[0] * x0 + g[1] * y0) else: noise = 0.0 tt = 0.5 - x1**2 - y1**2 if tt > 0: g = _GRAD3[gi1] noise += tt**4 * (g[0] * x1 + g[1] * y1) tt = 0.5 - x2**2 - y2**2 if tt > 0: g = _GRAD3[gi2] noise += tt**4 * (g[0] * x2 + g[1] * y2) return noise * 70.0 # scale noise to [-1, 1] win = pygcurse.PygcurseWindow(85, 70, 'Generate') octaves = 2 ysize = 150 xsize = 150 freq = 32.0 * octaves for y in range(ysize): for x in range(xsize): tile = SimplexNoise.noise2(x / freq, y / freq, octaves) win.write(str(tile) + "\n")