General
Introductions and general chat
50 PostsActivity in Discussion Forums
Resolved! What is the role played by key columns in a keyed table [ query join/performance ] ?
I would like to understand what is the underlying optimization or performance tweak that kdb+/q is able to extract when we apply key on one/more columns in the table. Key serves the purpose of helping join 2 or more tables via row to row match using ...
QR: Quick Response quite reasonable; quirkily rectangular
Turning a URL into a QR (Quick Response) code is an illuminating exercise. Following the description of the algorithm posted by Vidurangi Kalpana, and setting aside the business of representing a boolean matrix in print or on a screen, the steps are:...
Flouring the loaf
Now here’s a task that cries out for a simple solution: put a border round a matrix. My matrix is boolean and represents a QR code (yes, we’ll come to that) but it’s the same problem as, say, putting a 1px border on an image. So let’s examine it as w...
sym flipping back and forth when creating continues futures contacts based on volume
I am trying to create a continues futures contacts based on volume. But the problem I am facing is the symbols are flipping back and forth. How did you fixed the sym being flipping back and forth?posted my query on stackoverflow, but no luck with sol...
Resolved! Binary iteration question
Hi All, Given a binary list of any length e.g:test:00001111000111001101000b Is there some way to iterate through this with 2 values - e.g input:3 , output:2 So that every time the input is 1 at least 3 times in a row (input param) , we let the result...
