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Comment by atum47 | Hacker News Reader

Hi everyone, I made this a while ago just for fun. Perceptron was one of the first algorithms I wrote back in college when I was taking machine learning classes. So I thought how cool would be to write something fairly modern (not really) like a neural network using old tech like cobol. Hope you like it.

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Interestingly, perceptrons and Cobol are almost the same age.

"The perceptron algorithm was invented in 1958"[1]

"COBOL was designed in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC designed by Grace Hopper."[2]

[1] https://en.wikipedia.org/wiki/Perceptron

[2] https://en.wikipedia.org/wiki/COBOL

yeah, when I was writing the comment I remember my teacher telling us that neural networks were invented a long time ago and now (2017 when I took the class) they were coming back. that's why I wrote (not really)

When classifying it's often a good idea to feed the prediction into a sigmoid-function.

I have never seen cobol code before, only heard about it so thanks for posting some. What do rows like "01 ERR PIC S99V9999." mean?

I think the perceptron algorithm does not include a sigmoid, just a stepwise activation. https://en.wikipedia.org/wiki/Perceptron

ERR is the name of my variable "error" S indicates that this value is signed 99 is two digits V is a decimal separator and the other 9999 are 4 decimal places

http://www.csis.ul.ie/cobol/course/DataDeclaration.htm

And the 01 at the start of the line is the level number as explained in the link. It is how Cobol declared nested records, which Fortran and Algol lacked but became popular through PL/I, Pascal and C.

I think 01 line number ERR what you think it means PIC S99V9999 is like a printf format for the number field

Cobol can be actually quite modern.

https://www.microfocus.com/en-us/products/visual-cobol/featu...

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