![]() Also, the profiler is garbage when it comes to a lot of this stuff, which is why I switched to manually saving the times. I did not investigate object calls within nested functions, but I've seen some weird things. If you want reference behavior to boot, Java may be the way to go. The overhead in calling the Java object is high, but within the object, simple access and assign operations happen as fast as regular matlab objects. I also created a Java class and ran a similar test: 12.18 17.53 'jObj.field > in matlab for loop'Ġ.0043 0.0039 'jObj.get and t loop N times internally' Or: classdef TestHandleObj methods' //This calls get and set methods that loop internallyĠ.1574 0.3053 'TestHandleObj > methods' //get and set methods (internal loop) With classes defined like: classdef TestObj I created a very basic test function of the form: tic I was under the impression that the first call to a constant property would create an instance and then all future calls would reference that instance, ( Properties with Constant Values), but I no longer believe that to be the case. Getting that to work inside the Matlab IDE and debugger (which are very useful) would require deep and terrible hacks.ĭon't call a constant using m圜lass.myconst without creating an instance first! Unless speed is not an issue. If for some reason you must use direct access of constants, go with a plain function that returns the value.įor the sake of your sanity, stay away from the preprocessor stuff. If you're using a constant inside a loop, copy it to a local variable before entering the loop. chisquare chi2inv (P,2) inverse of the chi-square cumulative distribution function with 2. PEA pichisquareprod (sqrt (svd (val))) area calculation. chisquare chi2inv (0.95,2) inverse of the chi-square cumulative distribution function with 2 degrees of freedom at P 0.95. On my machine, reading this constant is about 100x slower than calling a plain function (22 usec vs. All functions in a script must be closed with an end. The other gotcha is that classdef properties and methods, especially statics like this, are slow. M圜onstants.SECONDS_PER_HOUR = 42 % this bug is a syntax error now M圜onstants() % "import" to protect assignment (IMHO this is overkill, but it's there if you want it.) function broken_constant_use And if you want to be thorough, you can protect against it by calling the M圜onstants() constructor at the beginning of a function, which forces Matlab to parse it as a class name in that scope. > M圜onstants.SECONDS_PER_HOURīut the damage is local. Translate EDIT: 20110618 10:01 CDT - reformat - WDR Hello, I am trying to write a code to calibrate a GARCH option pricing to market data and I have the following errors : Theme Copy Function keyword use is invalid here. If code accidentally tries to write to a constant, instead of getting an error, it will create a local struct that masks the constants class. See the Matlab documentation for "Object-Oriented Programming" under "User Guide" for all the details. Then reference them from any other code using dot-qualification. (Or, conversely, is a good reason to abandon back-compatibility.)ĭefine them in a class. This is probably the best option if you don't require back-compatibility to old Matlabs. The newer (R2008a+) "classdef" style of Matlab OOP lets you define constant class properties.
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