Matlab longest why

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Show older comments. Attaullah Shafiq on 24 May Vote 0. Answered: ahmed ibrahim on 11 Jan Longest Sequence of 1s. Show older comments. Brian Dunphy on 27 Apr Vote 1.

Edited: Sean de Wolski on 1 Oct I have a code for finding the longest sequence of consecutive ones but I am having problems with certain inputs giving improper results. John BG on 27 Apr Cancel Copy to Clipboard. And in 1st line of your function, do you really need to add head and tail zeros?

Answers 4. Azzi Abdelmalek on 27 Apr Edited: Azzi Abdelmalek on 27 Apr If n is a string. Daniel on 1 Oct What is the logic to combine all these operatins in such a way?

Thanks :. Matlab is an interpreter, not a compiler, so each new function or script that is called has some overhead in setting up debugging and trace-back information, and overhead in creating the "workspace" for the function. Traditional compilers such as C compilers do not explicitly set up debugging information at run-time: instead, at the time of interruption, the debugger looks up the current instruction pointer in a table to figure out where it is.

Traditional compilers such as C compilers do usually have to do some work setting up the stack, but not usually as much as Matlab does. For some common kinds of programs, it is theoretically possible in a language such as C to pre-allocate many of the local variables for all of the routines, turning stack-relative local references into fixed addresses.

Programs that can be compiled that way can have as little overhead for a subroutine call as storing the return address and performing a branch operation; on some processors, the return address gets stored in a very fast register while it is setting up the branch, making the call very fast. Matlab cannot reach that level of optimization. This level of optimization is not usually used in programs, but might be used for very very heavily optimized programs in non-interpreted languages.

One must keep in mind the difference between a low overhead calling procedure that could theoretically be used in a subset of programs, versus generalized calling procedures that do get used in practice. Procedure calls might not add much overhead in theory to straightforward programs in compiled languages, but Matlab is not one of those straightforward programs and it is not compiled. Sean de Wolski on 21 Mar Vote 0. You're correct!

There is overhead in calling a function. There is additional overhead if the function is new or if the command. James Tursa on 21 Mar For your specific example the functions will take slightly longer.

The functions need to be read in and parsed for one thing, and that will probably dominate the above example. But let's put that aside for the moment and not take this into account for the timing. When you call a function in MATLAB, it usually makes temporary shared data copies of the inputs for scalars it sometimes makes just a deep copy. So that takes extra time. The actual computation is the same for both, and the assignments to y and z will take the same amount of time.

But in the function case there will be extra temporary shared data copies of the inputs or temporary deep copies that will need to be cleared, so that takes additional time also.

But I would guess that the extra time for the function calls will still be pretty fast and the extra time spent doing it will probably be moot in most practical cases that are not this simple. Thank you for your answers! As you say, this would not be a problem for a simple task like this, but I have to run a program with a loop for s with a time step of 0. Ahh well, I guess we have to find a way to work around this! Once again, thank you! Matt Tearle on 22 Mar Just to mess with you, there are some other subtleties about the way MATLAB handles passing data to functions, which will come into play if x is a large array, rather than a scalar.

You will, however, get a temporary variable for the output Confused yet?