Convolution (the alternative to evolution)

[Gottservant]

Maybe the universe started with random phrases that combined together to make statements.

It would have been words like "you don't" and "know what you're talking about"...

 

[Mallon]

You're 27.

 

[USincognito]

I just saw someone using the below image as an avatar. The timing given this thread is nothing short of serendipity.

 

[arunma]

Maybe the universe started with random phrases that combined together to make statements.

It would have been words like "you don't" and "know what you're talking about"...

You call that a convolution? Ha! I'll show you a convolution.

No, really. That is the mathematical definition of the convolution operator. Cool, huh?

Now why they'd call it a "convolution," I will never know. But then again, I don't think there is a method to any of the various mathematical terminologies (except that they all sound equally cool).

 

[AV1611VET]

Maybe the universe started with random phrases that combined together to make statements.

It would have been words like "you don't" and "know what you're talking about"...

More like --- Let there be light.

• [bible]Genesis 1:3[/bible]

 

[Kripost]

I expected this thread to be a discussion on image processing...

 

[Dragar]

Now why they'd call it a "convolution," I will never know.

The word is from 'convolve' meaning to 'roll up' or 'roll over' or 'roll together'. There's definately a rolling involved, and an implied thing it's being rolled with, anyway.

And that's what happens when you convolve one function with another; you can imagine sliding (rolling) one function across the other. You know the rest of how it works, being a physics person, so I won't try and badly explain it in 5 minutes here.

 

[Markus6]

Maybe the universe started with random phrases that combined together to make statements.

It would have been words like "you don't" and "know what you're talking about"...

 

[MrGoodBytes]

God, I love owls.

 

[arunma]

The word is from 'convolve' meaning to 'roll up' or 'roll over' or 'roll together'. There's definately a rolling involved, and an implied thing it's being rolled with, anyway.

And that's what happens when you convolve one function with another; you can imagine sliding (rolling) one function across the other. You know the rest of how it works, being a physics person, so I won't try and badly explain it in 5 minutes here.

Interesting. As long as you're around, do you happen to know why they call a certain trigonometric operator the "tangent?"

 

[Dragar]

Interesting. As long as you're around, do you happen to know why they call a certain trigonometric operator the "tangent?"

Sorry. I had a think (perhaps related to the tangent of a circle in plane polar?) but I can't find a reason.

 

[Mystman]

Interesting. As long as you're around, do you happen to know why they call a certain trigonometric operator the "tangent?"

according to wiki..

http://en.wikipedia.org/wiki/Tangent#Trigonometry

 

[arunma]

Sorry. I had a think (perhaps related to the tangent of a circle in plane polar?) but I can't find a reason.

You know, back in middle school and high school, when I was learning about trigonometry and tangent lines of circles, I figured that there must be some connection between the two. At the time I thought that perhaps the tangent operator could be used to find the tangent line to a circle. Later in high school when I learned calculus, and learned that the slope of the tangent line of a circle centered on the origin is -x/y (whereas the tangent of the angle subtended with +x is y/x), I learned that this assumption was not correct. Of course I simply reasoned that if I learned enough math, I'd understand where the trigonometric terminologies come from.

OK, fast forward by over four years. I've got a math degree now, and I still don't have any clue why it's called a tangent. Therefore I summarily come to the conclusion that the people who named the trig functions were on drugs.

 

[Mystman]

As for convolution, first time I heard of the word was a few months ago when getting a class about digital signal processing (it has something to do with impulse responses..)

nice to know where the word comes from.

 

[arunma]

according to wiki..

http://en.wikipedia.org/wiki/Tangent#Trigonometry

I guess you learn something new every day! That's a very interesting geometric construction; I never thought of it that way (probably because it's not the most intuitive definition). It all makes sense now. But I still think it's stupid to call it a "tangent" on the basis that the tangent line of a circle at a specific point happens to be used in the construction. One day, I shall come up with a cooler name for this operator...but not today.

And this is all the more humorous in light of the post I wrote before reading your link.

 

[arunma]

As for convolution, first time I heard of the word was a few months ago when getting a class about digital signal processing (it has something to do with impulse responses..)

nice to know where the word comes from.

Yeah, the convolution is pretty useless. Technically it can be used to solve ordinary differential equations, but I've never needed it for that purpose. It comes up once in probability theory (and it saved me on my final!). But that's about it.

 

[Assyrian]

According to the Online Etymology Dictionary

tangent (adj.)
1594, "meeting at a point without intersecting," from L. tangentem (nom. tangens), prp. of tangere "to touch," from PIE base *tag- "to touch, to handle" (cf. L. tactus "touch," Gk. tetagon "having seized," O.E. þaccian "stroke, strike gently"). First used by Dan. mathematician Thomas Fincke in "Geomietria Rotundi" (1583). The noun also is attested from 1594; extended sense of "slightly connected with a subject" is first recorded 1825. Tangential is recorded from 1630; fig. sense of "divergent, erratic" is from 1787.

 

[FishFace]

Sorry. I had a think (perhaps related to the tangent of a circle in plane polar?) but I can't find a reason.

Take a line from the centre of a circle, intersecting the circumference, with angle to the horizontal A. The length of the segment of the tangent at the intersection from that intersection, to where it cuts the horizontal is given by tan(A).

 

[Dragar]

Ah-ha. That does explain it. Cool.

 

[Abongil]

You call that a convolution? Ha! I'll show you a convolution.

No, really. That is the mathematical definition of the convolution operator. Cool, huh?

Now why they'd call it a "convolution," I will never know. But then again, I don't think there is a method to any of the various mathematical terminologies (except that they all sound equally cool).

is t time?