11/21/2023 0 Comments Syntax for for loop in matlabTo keep it simple, just always use the &, and use const if you don't plan to change it, because copies can be expensive waste of time. With the &, the changes are kept, as its a reference to the original. Important: without the & py is a copy, and you can't change pertY (changes to py are lost). It will self delete, and you can iterate it with a range based for loop:Ĭout << py //py becomes a reference to each item in pertY, it stands for pertyY in a traditional loop. For the function that uses x and y as inputs, I'm trying to run x(1) for each instance of y, then x(2) and x(3). ![]() The scenario I'm working with has two variable sets, call them x and y where length(x) 3 and length(y) 6. PertY //same as a pointer when accessing! I've dabbled in a few programming languages and loops have been a weak spot for me, and MATLAB has been no different. PertY = (double*) fftw_malloc(nx*ny*sizeof(double)) Īnd you don't even change the code otherwise: In the second case, Matlab creates a 10k-element array, then it walks all elements of the array. Note that if you modify i in the loop body, the modified value will be ignored, as Zach says. Dynamic memory is a recipe for problems, esp if you are not used to it, and vectors hide this. The first loop creates a variable i that is a scalar and it iterates it like a C for loop. This is much safer than trying to eyeball it for some subtle difference or trying to catch the old matlab index 1 c++ index 0 or matlab variable type changed midstream type bugs.Īnything you are not absolutely sure of, you should do a side by side compare of a small isolated test run.Äon't forget to put your random numbers back in, and consider using the c++ library because rand() has a LOT of issues (both with randomness and lack of features).Īlso consider using a vector, which prevents having to use C malloc or C++ pointer nonsense. If you get the expected output, its good. you can expect some tiny differences in double values, moreso if you call any matlab routines inside the code (none here that I saw). Rands //make sure you generated enough that index won't go out of boundsĪnd then compare the c++ result to the matlab result for a few different rand sequences. ![]() Here we discuss For Loop in Matlab, appropriate syntax, and respective examples.For something this aggravating, you should replace the random numbers with a known stream or known value.Äouble rands //whatever values, have matlab generate this maybe If we iterate over single-column vector values, we can first take its transpose to create a row vector. ![]()
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