...the 2nd iteration forward (which might affect timing since DT$g is already allocated?), the result also propagates back to ans1 and therefore might (if R's optimizer deems it necessary? Not sure on this...) avoid another copy that DPLYR_fun and BASE_fun need to make? – Ken Will...

...memory management (e.g., that your methods do not return objects that they allocate). share | improve this answer | follow | ...

...es in the end. Variables for objects use pointers, Garbage Collectors use malloc and free, files are locked using OS handles; when something goes wrong in a Java or C# application knowing these fundamentals can greatly improve your understanding of what went wrong. Understanding resource allocation ...

...e main difference is the size: User-space can get away with statically allocating many variables on the stack, including huge structures and thousand-element arrays. This behavior is legal because user-space has a large stack that can dynamically grow. The kernel stack is neither large n...

...decided not to have a database per customer because of the way MongoDB allocates its data files. Each database uses it’s own set of files: The first file for a database is dbname.0, then dbname.1, etc. dbname.0 will be 64MB, dbname.1 128MB, etc., up to 2GB. Once the fil...

...do object oriented programming, unless you build a quite complex system of allocation of objects (I thought about that. it's feasible, but insane). In practice, you can however do "Singleton oriented programming": you have one instance of each object, and only one. What I do is: i define an object ...

...too artificial, you could mentally replace int by a very large dynamically allocated integer which is inherently non thread-safe and for which multiplications are extremely costly.] The member-function area is no longer thread-safe, it is doing writes now and is not internally synchronized. Is it a ...

...) { return Optional.ofNullable(parent); }. This looks expensive because it allocates an Optional every time! But if the caller unpacks it immediately, the object is extremely short-lived and is never promoted out of eden space. It might possibly even be eliminated by the JIT's escape analysis. The b...

...ifferent between the two languages. Here, the problem is that you want to allocate some resource (open a file, obtain a database cursor, etc), perform some arbitrary operation on it, and then close it in a safe manner even if an exception occurs. In Ruby, because blocks are so easy to use (see #9)...

... However, the real problem is in step #1. When many programs start, they allocate a single chunk of memory for their stack, and when they run out of that memory (often, but not always due to recursion), the program crashes due to a stack overflow. So in these languages recursion is slower and it ...