Should equality operators be approximate when defining numeric types based on floating point numbers?

For example, let's say you have a class Point which has floating-point components. It is tempting to overburden the equality operator to be able to do something like:

a = Point(1.1, 2.2)
b = Point(3.3, 6.6)
b /= 3
a == b // should always hold true

This could be achieved through an expression like abs(a-b) < epsilon. Is there a particular reason not to do something like this?

unit – Time / counterclockwise for Vector2.Rotate (floating angle)

I'm doing a 2D game in Unity, and from what I understand, their the convention is that an angle of 0 is rising and by increasing the angle rotates the object in the counter-clockwise direction.

Sidenote: I've formulated this hypothesis by looking at the rotation.z value in the inspector window of a transformation. When it is 0, the object transform.up point to positive y. Increasing rotation.z rotates the object counter-clockwise, that is to say transform.up points to negative X at an angle of 90 degrees. Let me know if it's wrong.

Given the convention that increasing angle turns counterclockwise, what method does my method Vector2.Rotate(this Vector2 vector, float angle) make?

My question is whether to do Vector2.up.Rotate(90) would rotate clockwise or counterclockwise, where in the clockwise direction would give Vector2.right and in the counterclockwise direction would give Vector2.left.

At first, it seemed like an initiative obviously clockwise direction. It's a positive number, so it turns clockwise. I do not know where this bias comes from but using Rotate(90) feels like it should be turned to the right (clockwise).

After thinking about it, I think it would be more logical to have Rotate(90) turn counter-clockwise. As the universe assumes higher / positive angles, the method must also respect this rule. But for some reason, it does not seem intuitive to me to rotate something in a clockwise direction, I should call Rotate with a negative number. Rotate(-90) // clockwise.

Is there a factual means to make this decision?

[GET][NULLED] – Woo Floating Cart – An interactive floating wagon v1.3.7.1

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(GET) (NULLED) – Woo Floating Cart – An interactive floating cart v1.3.7.1

low level – Why do many programming languages ​​and applications use an integer instead of a floating point to represent time?

In my experience, the value of time is mainly represented by an integer, by programming languages ​​(C / Java / Golang / Javascript (*) …), and by databases (MySQL, Postgres …), with the exception maybe of some graphical interfaces / game engines and I still think it's normal. But when I thought more about it, I found that it might be more logical to represent floating point time.

Some of my points:

  • The value of time is most often used in terms of continuous sequence of events. (For example: has this contract expired, this football match is over?). I do not really remember at a time when I need to compare 2 time values ​​are equal. So, the value of integer precision is not really useful in this case.
  • Secondly, when precision time is needed (say we have to represent an exact time such as 01/01/2020 UTC). The floating point of 64 bits can represent it well. I like it in javascript, where the value is represented by a number – 64-bit floating point millisecond number from an epoch.
  • The use of 64-bit floating point to store time is actually a saving of space when you have to represent a fraction of unity. As in golang and C, you need 2 integers (both 64 bits), 1 for the number of seconds from the epoch, 1 for the number of nano seconds.

I can think of a few reasons:

  • This is how the hardware works (CPU?)?

So what do you think is the reason (s)? Thank you.

(*) Javascript does not have a native integer type (until recently with BigInt). So, the date value is actually a number, which is a 64-bit floating point, but the value is always an integer.

arithmetic – floating point subtraction

if $ x = 1.0e38 = 1.0 * 10 ^ {38} $ and $ y = $ 3.0
I want to find $ (x-x) + y $ and $ (x + y) -x $
I think the value of (x-x) + will be just subtract $ x-x = 0 + y = 3.0 = 3.0 $
but how can I make a different basic addition? $ (x + y) -x $
I think the idea is addition $ (x + y) $ then subtract $ -x $ using floating point, I tried to convert $ y = $ 3.0 binary as $ 1.1 * $ 2 ^ 1
but what about $ 10 ^ {38} $ in binary?

Storage – Is a paraffin-oiled floating lid useful in a dark room?

I visited a cellar that used a large stainless steel tank to distribute wine. The tank had a spout at the bottom and a floating lid at the top. It was said that paraffin oil was poured on top of the floating lid, so as to fill the voids and provide an inert and airtight top. As the wine was dispensed from below, the lid simply sank with the rest of the volume.

Yes, there are many ways to store photochemistry: an accordion bottle, the addition of inert objects in the bottle to fill the space, but even with a smaller bottle! I am not interested in other storage methods or even stacking these methods against each other.

No, what I would like to know, it's Does this method take place with photochemistry?

The oil should float on the top in the same way as with the wine, but I'm not convinced of its inertia with photochemistry.


Edit for comments:

How could you get reusable solutions in the container without disturbing the flowing lid? It's not like you're drinking those things, I hope.

Adonal part with 2 parts of lime. Float the Grand Marnier and add sparkling water. I thought everyone drank these ??

Because of my limited time these days, I develop once or twice a month and I do all the necessary things in one go. This process intrigued me for use with commercial chemicals for before I mix them by dint of work. (I've got a bottle of solution, for example, which was between the half-full and the full 1/8 for almost a year now.)

The question can be a little cleaner with a specific target chemistry list. – The real question is how much reaction can occur between a given chemistry and an oil, because it should never come into contact with chemistry if it is done correctly.

See the comment above. Because of my own process, I would like to know all the reactions at all stages: developer, stop, fix, perma-wash. I do not think Photo-Flo goes bad so do not worry about that one.

Special webpage effect of floating attractive balls [on hold]

I came across this website and I was amazed by its background effects, where floating balls collide and aggregate each time the mouse cursor pauses. . Does anyone know how to do it?

algorithms – Calculate milliseconds and avoid floating numbers

I have a variable that increases / decreases 0 at 255 each (X) millisecond. so:

(X) x 255 = time in milliseconds / 60000 = minute

(X) millisecond is a variable that only increases by itself, for example after each push of a button:

(X) + (X) x 255 = time in milliseconds / 60000 = minute
(X) + (X) + (X) x 255 = time in milliseconds / 60000 = minute
etc.

What number should we use in (X) so that whenever it increases I get +1 exit minute.
I want a whole number not a float.

The language is C ++ if it helps anyway …

floating point – Denormalizing a binary number with hidden bit

For the binary representation with hidden bit, the normalized representation is as follows:

$$ x = pm 1.d_1d_2 dt cdot beta ^ {E} $$

Considering the following formula denormalization:
$$ begin {align}
X
& = pm 2 ^ 0 + beta ^ E sum_ {i = 1} ^ {t} d_i cdot beta ^ {- i} \
& = pm 1 + sum_ {i = 1} ^ {t} d_i cdot beta ^ {E-i}
end {align} $$

or: $ beta $ is the base, $ E $ is the exhibitor.


If we start from the number $ 0.011. If I am right, I get it:
– the normalized number would be: $ 0.11 cdot 2 ^ {- 1} $
– the standardized bit with hidden bit would be: $ 1.1 cdot 2 ^ {- 2} $

So, using the formula above, if I insert the numbers of the last number, then I should get the first number:
$$ begin {align} x & = pm1 + 1 cdot2 ^ {- 2-1} \
& = pm1 + 2 ^ {- 3} \
& = pm 1 + 0.001 \
& = 1 + 0.001 \
& = 1,001
end {align} $$

but that's not the number $ 0.011 from where I started. So, does the error lie in my way of proceeding or in the given formula?

one shot – I'm completely new to Tales from the Floating Vagabond, how do I get started?

One of my tables decided that it was time to go to a test. We have written a list of systems that look interesting, but we have not played, and I have to roll.

The dice decided it was going to be Tales of the floating vagabond.

I've met the name of this game in a few situations and I know that there are versions with typos and grammatical errors that lead to unbalanced player characters and similar problems.

I am completely new to Tales of the floating vagabond, how can I start?

What material should I avoid to circumvent these problems, what information is needed to help me understand, and then to teach the system in a relatively short period of two weeks?