The History of "i" [modified]
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Hockey wrote:
You know the ubiqious "i" found in almost every example of a for loop for newbies?
I have always used
xfor that. It's the new-old-cool thing. :) Jeremy FalconHi, the i history is simple. In mathematics, when dealing with matrices and vectors, you usually call a_i_j as the element at the i-th row and j-th column. Then, when iterating over a vector, you usually use this notation taken from linear algebra. Nowadays, this behaviour has been extended to almost every for loop. A polar bear is a bear whose coordinates has been changed in terms of sine and cosine.
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In mathematics, i, j, and k are universal - they are used as integers, indices and to designate imaginary axes for vector quantities. This bled over into FORTRAN when computers were run almost exclusively for mathematicians and has stuck for decades. The use of n is a fairly new development, but it was only a matter of time before we ran out of integers. Fortunately, x and y are still usable for real numbers, and one has to grant them credit - there are an awful lot of real numbers. These valiant variables don't get half the credit they deserve... Engineers have done what we can to preserve the available pool of numeric variables. We use x, y, and z to designate unit vector directions, thereby reducing the load that i, j, and k have to carry. Recognizing the need to conserve, we have also adopted the variable s to designate the special value jw, mainly because it makes the math a lot easier. "...a photo album is like Life, but flat and stuck to pages." - Shog9
Roger Wright wrote:
The use of n is a fairly new development, but it was only a matter of time before we ran out of integers.
You must be talking about Chuck Norris. He ran out of integers. Twice! :-D
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evilnoodle wrote:
How does one discover a letter?
I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was. Okay, so you don't discover letters, you create them. Reminds me though of an old George Carlin news report where he says that scientists had discovered a hitherto undiscovered new number between 6 and 7. It's "bleen'. Of course, he was thinking in terms of integers. But I had pictures in my head of a group of scientists who each had an extra appendage on their left hands. What I didn't look forward to was having to quote numbers like bleen thousand bleen hundred and bleenty-bleen. Lilith
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The possibilities are transcendental when you get David and Ryan going on Mathematics. Add in Chris and well... somehow it all equals "i" in the end...:laugh:
The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.
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Chris Maunder wrote:
i is reserved for sqrt(-1)
We're not going to start this discussion again...are we? :~
They dress you up in white satin, And give you your very own pair of wings In August and Everything After
I'm after everything
just square it lol Pablo
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
I'd look to the early definitions of Fortan (I think, it's too many languages ago now) which used the first letter of a variable to define the type (i, j, and k being the first 3 of the integer range). Of course you can bet that start point for integers came either from mathematical formula or being the first letter in the word integer, but I don't know. Happy hunting, Ken R.
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Chris Maunder wrote:
i is reserved for sqrt(-1)
It depends. In electrical engineering, i is reserved for alternate current and, hence, we use j to refer to sqrt(-1). Francisco Silver at last!!
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evilnoodle wrote:
How does one discover a letter?
I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was. Okay, so you don't discover letters, you create them. Reminds me though of an old George Carlin news report where he says that scientists had discovered a hitherto undiscovered new number between 6 and 7. It's "bleen'. Of course, he was thinking in terms of integers. But I had pictures in my head of a group of scientists who each had an extra appendage on their left hands. What I didn't look forward to was having to quote numbers like bleen thousand bleen hundred and bleenty-bleen. Lilith
A number between 6 and 7. "The Nobel Prize in mathematics was awarded to a California professor who has discovered a new number! The number is bleen, which he claims belongs between 6 and 7." --George Carlin Seriously, this is like Guinness world records: "Please watch closely as this brave man attempts to set a new world record, that up until now didn't exist!" --- AWE.....AMAZING!!!!! you can't forget something you never knew...
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evilnoodle wrote:
How does one discover a letter?
I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was. Okay, so you don't discover letters, you create them. Reminds me though of an old George Carlin news report where he says that scientists had discovered a hitherto undiscovered new number between 6 and 7. It's "bleen'. Of course, he was thinking in terms of integers. But I had pictures in my head of a group of scientists who each had an extra appendage on their left hands. What I didn't look forward to was having to quote numbers like bleen thousand bleen hundred and bleenty-bleen. Lilith
Lilith.C wrote:
I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was.
I thought it was the other way around. I'm remembering crucifixes marked INRI "Jesus of Nazareth king(Rex) of the Jews" from sundayschool.
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Lilith.C wrote:
I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was.
I thought it was the other way around. I'm remembering crucifixes marked INRI "Jesus of Nazareth king(Rex) of the Jews" from sundayschool.
dan neely wrote:
Lilith.C wrote: I don't remember the history other than reading it in a Heinlein novel, but I believe the story is that 'i' as a letter was added to the alphabet much later than most letters. Before that the letter 'j' was used where the 'i' was. I thought it was the other way around. I'm remembering crucifixes marked INRI "Jesus of Nazareth king(Rex) of the Jews" from sundayschool.
That could well be. As J sajd, J don't remember the hjstory that well. Ljljth
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
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I think I reserved i for 2 people at 7:00. :doh:
The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.
(i)bid to the (I)nteger:laugh: DB_Cooper1950