Jump to content

I BROKE KSP.


InsanityYT

Recommended Posts

Welp, I completely broke KSP. 

If for whatever reason, you can't watch the video, I was trying to see what the highest velocity possible was in KSP 1.1.3. I went about this using the Boost in Hyperedit. (I slowly put the boost factor higher.) Eventually, I reached this speed: 111,039,787,973,867 meters per second. Doing some math, that is 370,388.86 Times the speed of light. Then, I set the boost factor to some insanely high number, and immediately, my height bar went blank and my speed said NaNm. Immediately, I was confused. Then I realized that NaNm was likely a placeholder if the game could not possibly list your velocity. Meaning, theoretically, I had reached ∞ m/s. Also, this bit scientifically explains the blank screen and non-existent height bar, 

Spoiler

Given that I was traveling at nearly 400K times the speed of light, and how moving faster than light allows you to travel back in time, I had in fact traveled so far back that I am at a time that predates the Big Bang.

Overall, very interesting.

Link to comment
Share on other sites

54 minutes ago, InsanityYT said:

So the infinity speed thing is true?

absolutely not. Floating point numbers in computers have concepts of + and - infinity, as well as NaN.
NaN literally means "Not a Number", and is the result of an operation with mathematically undefined result, such as division by zero. Any operation on NaN, results in NaN.

In math, infinity is quite well defined. If your speed had gone infinite, it would be +infinity.

Link to comment
Share on other sites

15 hours ago, Cadet_BNSF said:

Well, the indeterminate form 1/0 = infinity, so he could be right

I believe it's actually undefined, not infinity. They're quite distinct things. Any answer to x/0 is equally valid, they're all nonsense.

Link to comment
Share on other sites

6 hours ago, Lelitu said:

I believe it's actually undefined, not infinity. They're quite distinct things. Any answer to x/0 is equally valid, they're all nonsense.

Correct, as 0 is neither positive nor negative.  If you specifically use a positive or negative 0 you do get a defined result for x/0, (so long as x<>0).

Link to comment
Share on other sites

NaN in this case means a calculation error, likely from an out of bounds parameter (the m is just a suffix).

20 hours ago, Chakat Firepaw said:

Correct, as 0 is neither positive nor negative.  If you specifically use a positive or negative 0 you do get a defined result for x/0, (so long as x<>0).

This is not correct. What number, when multiplied by 0, will yield a non-zero x? Divide by zero is undefined, by definition. It is not infinity or any other number.

Link to comment
Share on other sites

Just now, Red Iron Crown said:

This is not correct. What number, when multiplied by 0, will yield a non-zero x? Divide by zero is undefined, by definition. It is not infinity or any other number.

+0 and 0 are not the same thing, (it's sometime relevant to have a 0 which is not simply non-negative but actually positive).  x/+0 is defined, (for x<>0), but not reversible.

What makes x/0 undefined isn't the inability to reverse it but that it generates an infinite number of results, (defining an infinitely large circle on the complex plane).

 

Link to comment
Share on other sites

2 minutes ago, Chakat Firepaw said:

+0 and 0 are not the same thing, (it's sometime relevant to have a 0 which is not simply non-negative but actually positive).  x/+0 is defined, (for x<>0), but not reversible.

Zero is neither negative nor positive. It is not defined, being irreversible means you break algebra, which is not an acceptable result.

You can define a limit as the denominator approaches zero from the positive or negative side, but that is not the same as x/0 being defined.

2 minutes ago, Chakat Firepaw said:

What makes x/0 undefined isn't the inability to reverse it but that it generates an infinite number of results, (defining an infinitely large circle on the complex plane).

I'm not sure what you're talking about here, to be honest. It doesn't generate any results, because any result breaks algebra.

It's really simple:

x / 0 = y

thus x = y * 0

For non-zero x, no y satisfies the above. It's undefined.

Link to comment
Share on other sites

38 minutes ago, Red Iron Crown said:
46 minutes ago, Chakat Firepaw said:

+0 and 0 are not the same thing, (it's sometime relevant to have a 0 which is not simply non-negative but actually positive).  x/+0 is defined, (for x<>0), but not reversible.

Zero is neither negative nor positive. It is not defined, being irreversible means you break algebra, which is not an acceptable result.

You can define a limit as the denominator approaches zero from the positive or negative side, but that is not the same as x/0 being defined.

A mathematician and a computer scientist walk in to a bar. Neither of them believes the other about signed zeroes.

Quite a few numeric representation systems in computing require the existence of a signed zero. The example I remember from my university days is ones' complement numbers, but the IEEE standard for floating point numbers that most computers use, IEEE 754, also includes the concept.

That said, IEEE floats also throw the same NaN exception for division by both positive and negative zero. Also, the wikipedia pages I linked describe complicated edge cases where both signed zeroes and division by zero are defined and useful. So I'm just going to buy the next round and back away slowly.

 

Link to comment
Share on other sites

5 hours ago, Whackjob said:

7IU6628.png

I'm partway there already.

That craft is too small for whackjob.  I do not believe you built that.

---

The division by zero question is easily answered by just plotting a 1/x graph: 

https://www.desmos.com/calculator/5jffkbhxlw

As you can see, when you are approaching from the positive side, y becomes +infinity, and from the negative side, it becomes -infinity.  And since at x=0, y cannot be both positive infinity and negative infinity at the same time, it's undefined, not infinity. 

 

Link to comment
Share on other sites

On 22/05/2017 at 6:43 PM, Red Iron Crown said:

Zero is neither negative nor positive. It is not defined, being irreversible means you break algebra, which is not an acceptable result.

Well there's your problem:  You are stopping at algebra, CS needs signed zeros as do some of the things involved in other BMath major's degrees, (I went to UWaterloo, they don't have a Math Department they have a Math Faculty[1]).

And algebra has all kinds of irreversible functions, a trivial example would be f(x)=1.  Another example would be sgn(x), for that matter sin(x) can't be reversed except by convention, (sin-1(sin(5π/4)) = -π/4 because we assume that -π/2 ≤ sin-1(x) ≤ π/2).

All undefined means as a result of a function is that there is either more than one result or no results.  To be defined a function must take the elements of set X and assign it to a single member of another set Y, it does _not_ require the reverse where the subset of Y that had a member of X assigned to it can be assigned to a single member of set X.

 

[1] I may not have been a mathie, (started in ChemEng, later switched to Chemistry), but it's hard to avoid picking things up when the MC comfy lounge is where you tended to hang out.

Link to comment
Share on other sites

2 minutes ago, Chakat Firepaw said:

Well there's your problem:  You are stopping at algebra, CS needs signed zeros as do some of the things involved in other BMath major's degrees, (I went to UWaterloo, they don't have a Math Department they have a Math Faculty[1]).

Another person has pointed this out to me privately, but thank you, fellow Canadian. :)

2 minutes ago, Chakat Firepaw said:

And algebra has all kinds of irreversible functions, a trivial example would be f(x)=1.  Another example would be sgn(x), for that matter sin(x) can't be reversed except by convention, (sin-1(sin(5π/4)) = -π/4 because we assume that -π/2 ≤ sin-1(x) ≤ π/2).

 Sure. Division is not one of those irreversible functions, though.

2 minutes ago, Chakat Firepaw said:

All undefined means as a result of a function is that there is either more than one result or no results.  To be defined a function must take the elements of set X and assign it to a single member of another set Y, it does _not_ require the reverse where the subset of Y that had a member of X assigned to it can be assigned to a single member of set X.

This was never my assertion. My assertion was making the always reversible operation of division irreversible breaks algebra.

2 minutes ago, Chakat Firepaw said:

 

[1] I may not have been a mathie, (started in ChemEng, later switched to Chemistry), but it's hard to avoid picking things up when the MC comfy lounge is where you tended to hang out.

Hard to study CS without being at least somewhat of a mathie. I think of CS as applied discrete mathematics. :)

Link to comment
Share on other sites

2 minutes ago, Red Iron Crown said:

 Sure. Division is not one of those irreversible functions, though.

So long as you stay out of the parts of math that generate signed zeroes.

2 minutes ago, Red Iron Crown said:

Hard to study CS without being at least somewhat of a mathie. I think of CS as applied discrete mathematics. :)

There is a long-standing "student quote" at UWaterloo attributed to a fair portion of students in CS upon asking why they have to take so many math courses:

"I'm earning a BWhat?"

(The CS degree at UWaterloo is a BMath(CS).)

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...