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Challenges Is it part of the mandelbrot set?

Haskell, 66 bytes -7 bytes thanks to Razetime‭ import Data.Complex (\c->(<2).magnitude$(iterate(\z->z*z+c)c)!!16) I use the fact, that if the result is bigger than 2, it will be fore...

posted 6mo ago by Arpad Horvath‭  ·  edited 6mo ago by Arpad Horvath‭

Answer
#7: Post edited by user avatar Arpad Horvath‭ · 2023-11-13T02:02:39Z (6 months ago)
Shorter
  • Haskell, 73 bytes
  • ```
  • import Data.Complex
  • (\c->(<2).magnitude$last$take 16$iterate(\z->z*z+c)c)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 16 elements from the list, so with the `last` function I get the last element which was iterated 15 times, that is $z_{16}$ (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 16$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
  • Haskell, 66 bytes
  • -7 bytes thanks to Razetime‭
  • ```
  • import Data.Complex
  • (\c->(<2).magnitude$(iterate(\z->z*z+c)c)!!16)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 16 elements from the list, so with the `last` function I get the last element which was iterated 15 times, that is $z_{16}$ (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 16$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
#6: Post edited by user avatar Arpad Horvath‭ · 2023-11-11T11:25:47Z (6 months ago)
+import
  • Haskell, 53 bytes
  • ```
  • (\c->(<2).magnitude$last$take 16$iterate(\z->z*z+c)c)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 16 elements from the list, so with the `last` function I get the last element which was iterated 15 times, that is $z_{16}$ (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 16$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
  • Haskell, 73 bytes
  • ```
  • import Data.Complex
  • (\c->(<2).magnitude$last$take 16$iterate(\z->z*z+c)c)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 16 elements from the list, so with the `last` function I get the last element which was iterated 15 times, that is $z_{16}$ (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 16$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
#5: Post edited by user avatar Arpad Horvath‭ · 2023-11-11T06:50:20Z (6 months ago)
Back to 16, ay z_1 is the original
  • Haskell, 53 bytes
  • ```
  • (\c->(<2).magnitude$last$take 17$iterate(\z->z*z+c)c)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 17 elements from the list, so with the `last` function I get the last element which was iterated 16 times (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 17$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
  • Haskell, 53 bytes
  • ```
  • (\c->(<2).magnitude$last$take 16$iterate(\z->z*z+c)c)
  • ```
  • I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.
  • `iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 16 elements from the list, so with the `last` function I get the last element which was iterated 15 times, that is $z_{16}$ (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.
  • Testing:
  • ```
  • import Data.Complex
  • f=(\c->(<2).magnitude $ last $ take 16$ iterate (\z -> z*z+c) c)
  • map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
  • ```
  • gives
  • ```
  • [False,True,False]
  • ```
  • Or if you like it better to print to the standard output:
  • ```
  • main = do print $ map f [(-1.8620690) :+ (-0.3448276), 0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
  • main
  • ```
#4: History hidden by user avatar Arpad Horvath‭ · 2023-11-11T06:02:22Z (6 months ago)
Detailed history before this event is hidden because of a redaction.
Haskell, 53 bytes

```
(\c->(<2).magnitude$last$take 17$iterate(\z->z*z+c)c)
```

I use the fact, that if the result is bigger than 2, it will be forever then, so I don't need to check this relation in each iterations. It is enough to check it in the end.

`iterate(\z->z*z+c)c` gives us a list of the results, the original `c` is the first, then I take 17 elements from the list, so with the `last` function I get the last element which was iterated 16 times (the first 0 times, the nth element n-1 times). Then I get the absolute value, and compare it with 2.

Testing:

```
import Data.Complex

f=(\c->(<2).magnitude $ last $ take 17$ iterate (\z -> z*z+c) c)
map f [(-1.862069) :+ (-0.3448276),0.3448276 :+ 0.3448276,0.2068966 :+ 0.7586207]
```

gives

```
[False,True,False]
```


Or if you like it better to print to the standard output:


```
main = do   print $ map f [(-1.8620690) :+ (-0.3448276),  0.3448276 :+ 0.3448276, 0.2068966 :+ 0.7586207]
main
```
#3: Post edited by user avatar Arpad Horvath‭ · 2023-11-11T06:02:22Z (6 months ago)
Some hints how does it work

The detailed changes of this event are hidden because of a redaction.

#2: Post edited by user avatar Arpad Horvath‭ · 2023-11-11T05:44:03Z (6 months ago)
print version

The detailed changes of this event are hidden because of a redaction.

#1: Initial revision by user avatar Arpad Horvath‭ · 2023-11-11T05:24:50Z (6 months ago)

The detailed changes of this event are hidden because of a redaction.