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uri:

"at://did:plc:nzrozayxq764zbgl4qtp5ald/app.bsky.feed.post/3jubmsj3q262z"

cid:

"bafyreibvvkuqhus7epmljgcgmepgxwcpaur3eejibvstagxb2p6us7l6zm"

value:

text:

"floating point: NaN and infinity"

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"app.bsky.feed.post"

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images:

• alt:

  "title: NaN and infinity
  
  panel 1: NaN stands for "not a number"
  
  It means the result of the calculation is undefined. 0/0 = NaN, sqrt(-1) = NaN
  
  panel 2: infinity
  
  "infinity" just means "this number is too big for floating point to handle". There are two infinities: one positive, one negative.
  
  1 / 0 = inf
  -1 / 0 = -inf
  inf - 10 = inf
  inf - inf = NaN
  
  panel 3: NaNs spread
  
  As soon as one NaN gets in, it gets everywhere
  
  NaN * 5 = NaN
  NaN + 2 = NaN
  
  panel 4: NaN and infinity: the bits
  
  A floating point value is NaN or infinity if the bits in the exponent are all 1, like this:
  
  (picture of a 0, eleven 1s, and 52 0s)
  
  the eleven 1s are the exponent
  
  It's infinity if the significand bits are all 0, otherwise it's NaN
  
  There are 2^52 values like this: 2 of them are ±infinity and the other 2^52-2 are NaN
  
  We usually treat NaN like a single value though.
  
  panel 5: 2^1024 = infinity
  
  here's what that looks like in Javascript:
  
  >> 2.0**1023
  8.98846567431158e+307
  >> 2.0**1024
  Infinity
  "

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createdAt:

"2023-04-26T12:50:56.986Z"