So I was playing with the structures program from '73 and I want to add an element to it -- a fair amount of searching showed me several algorithms for the element - which is actually quite tricky to code.
One suggestion from a friend was this code from a well known source, which is available in PDF files only - it looks ok so I scanned and then fixed the code -- it runs nicely - but I noticed that it has listed four coordinates for a shell - X, Y and Z vectors but is declared as X(3) etc. which is ok if you use a triangle but a rectangle is going to run out of memory spaces.
Easy fix as, but the interesting question is how much production code is based on this published code and I wonder if it was picked up -- the code I am referring to is well known in the field.
I saw some interesting code in a Journal article for doing co-ordinate transformations -- looked ok , so I downloaded the file, and got it running against a newer bit of code. It gave an answer which was the mirror image on plotting from the newer code. I tried them both on a problem with an obvious answer and the old code gives an answer that looks ok until you think about it - the newer code is more correct.
I wonder how much old code has such errors.
John