In every model which are creating in Simulink are consist of some blocks and wires, I think blocks are shared library in the backend of Matlab, now I would like to know are those wires are shared library like blocks?
another question is:
when we click on the play icon, we can see something in the taskbar which shows, compiling... my question is, Is at this phase Matlab building .exe file that containing those shared libraries?
Yes, you are right, it is compiling and than running the functions for each simulation step, see here. This is efficient since Simulink simulates multiple time steps of the same model and; therefore, it is worth invest a little time into compiling.
You can note the compiling if you use the Matlab-Code function block, where you need to activate code-generation. Nevertheless, you need the Code Generation Toolbox to divert the model as an .exe.
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I am currently working on the implementation of some C-Code in a Simulink model using the S-Function Builder block.
The code uses various timers and counters, which are defined as static variables to enable the access to the data in following simulation steps.
However, if I start the simulation MATLAB crashes without error message ('Fatal Exception'). To test I defined the variables without the 'static' statement. The Simulation works in this case, however with (logically) wrong results of the S-Function.
Has anybody else faced similar issues or knows how to declare static variables in Simulink?
P.S.
I know I could use Work Vectors, which I do not intend to do, since it would result in huge efforts in adopting the function to do so.
Furthermore I could simply build a feed-back loop in the model using a memory block. For approximately 100 variables this solution would also be pretty impractical.
Not a solution, but a possible workaround is to use the coder.ceval functionality. I have used this to wrap a C-function with similar (static variables used as counters) function. The coder.ceval call is then placed in an embedded matlab block. Possibly some definitions of the interfaces must also be made (structures / bus objects).
Check coder.ceval, coder.rref and coder.wref for the call structure.
It seems like it was a bug in Simulink or the MinGW Compiler. However I tore down the code, ending up with it crashing with the call of one specific variable. I renamed the variable, since I could not find any error in the syntax. Now everything works fine...
The variable name had various underscores and capital letters - in case anyone makes similar experiences.
I implemented a (medium to big) simulink model in v2012b.
I thought it would work also in 2010bSP2, but it didn't. Some mask blocks are not opening and other strange errors.
In previous versions of simulink there was a "save as simulink 201x" model to force compatibility, but I couldn't find it anymore in 2012b.
Any clues on how to avoid rework?
Starting with 2012b, and the new interface, they have moved the option to the menu:
File / Export Model to / Previous Version
The feature never seems to fully work, and I often get warnings when first loading a model into an older version, so I would recommend giving your model a thorough check over and test. I always save again from the correct version, to clear the warnings.
The refactoring for a New Simulink Version can show up at several points.
Your own libraries: There is a feature called "Forwarding Tables" that allows you to specify where a block in the new library is (I suppose you will have to refactor your libraries as well, and probably someone else uses those libraries too)
It sounds like a biiig hack (and it is) but i found it sometimes the path of lowest resistantce... Just open your model in the Editor of your choice and replace the block paths whith the common refactoring funcitons. It is terrible i know but Simulink really lacks of refactoring functions...
Is there a supported way to have an Ada program call out to GNAT to compile a source file, and then load the result dynamically?
(By 'supported' I mean: better than shelling out to gnatmake.)
Background: I have a program whose configuration files contain code. Right now I have an LLVM-based library, written in C++, which I have C bindings to and call out to from Ada, which handles this: it loads the configuration files, JIT compiles them into (commendably fast) machine code, and then I call out to them from Ada.
This is horrible.
It would be far cleaner to simply write the configuration in Ada, and compile and link it against the program. But I don't want to force the end user to have to set up a build system. What I'd like is for the end user to just point my program at the configuration files, and then have the program compile and dynamically load them invisibly, without the user needing to care.
This sounds like exactly the sort of thing that someone's already done. Have they? (I only care about Unixoids like Linux, if that helps.)
A friend of mine needs to implement some statistical calculations in hardware.
She wants it to be accomplished using VHDL.
(cross my heart, I haven't written a line of code in VHDL and know nothing about its subtleties)
In particular, she needs a direct analogue of MATLAB's betainc function.
Is there a good package around for doing this?
Any hints on the implementation are also highly appreciated.
If it's not a good idea at all, please tell me about it as well.
Thanks a lot!
There isn't a core available that performs an incomplete beta function in the Xilinx toolset. I can't speak for the other toolsets available, although I would doubt that there is such a thing.
What Xilinx does offer is a set of signal processing blocks, like multipliers, adders and RAM Blocks (amongst other things, filters, FFTs), that can be used together to implement various custom signal transforms.
In order for this to be done, there needs to be a complete understanding of the inner workings of the transform to be applied.
A good first step is to implement the function "manually" in matlab as a proof of concept:
Instead of using the built-in function in matlab, your friend can try to implement the function just using fundamental operators like multipliers and adders.
The results can be compared with those produced by the built-in function for verification.
The concept can then be moved to VHDL using the building blocks that are provided.
Doing this for the incomplete beta function isn't something for the faint-hearted, but it can be done.
As far as I know there is no tool which allow interface of VHDL and matlab.
But interface of VHDL and C is fairly easy, so if you can implement your code(MATLAB's betainc function) in C then it can be done easily with FLI(foreign language interface).
If you are using modelsim below link can be helpful.
link
First of all a word of warning, if you haven't done any VHDL/FPGA work before, this is probably not the best place to start. With VHDL (and other HDL languages) you are basically describing hardware, rather than a sequential line of commands to execute on a processor (as you are with C/C++, etc.). You thus need a completely different skill- and mind-set when doing FPGA-development. Just because something can be written in VHDL, it doesn't mean that it actually can work in an FPGA chip (that it is synthesizable).
With that said, Xilinx (one of the major manufacturers of FPGA chips and development tools) does provide the System Generator package, which interfaces with Matlab and can automatically generate code for FPGA chips from this. I haven't used it myself, so I'm not at all sure if it's usable in your friend's case - but it's probably a good place to start.
The System Generator User guide (link is on the previously linked page) also provides a short introduction to FPGA chips in general, and in the context of using it with Matlab.
You COULD write it yourself. However, the incomplete beta function is an integral. For many values of the parameters (as long as both are greater than 1) it is fairly well behaved. However, when either parameter is less than 1, a singularity arises at an endpoint, making the problem a bit nasty. The point is, don't write it yourself unless you have a solid background in numerical analysis.
Anyway, there are surely many versions in C available. Netlib must have something, or look in Numerical Recipes. Or compile it from MATLAB. Then link it in as nav_jan suggests.
As an alternative to VHDL, you could use MyHDL to write and test your beta function - that can produce synthesisable (ie. can go into an FPGA chip) VHDL (or Verilog as you wish) out of the back end.
MyHDL is an extra set of modules on top of Python which allow hardware to be modelled, verified and generated. Python will be a much more familiar environment to write validation code in than VHDL (which is missing many of the abstract data types you might take for granted in a programming language).
The code under test will still have to be written with a "hardware mindset", but that is usually a smaller piece of code than the test environment, so in some ways less hassle than figuring out how to work around the verification limitations of VHDL.
I'm doing a research project on random forest algorithm. I have found numerous implementations of the algorithm but the main part of the code is often written in Fortran while I'm completely naive in it.
I have to edit the code, change the main parameters (like tree depth, num of feature variables, ...) and trace the algorithm's performance during each run.
Currently I'm using "Windows-Precompiled-RF_MexStandalone-v0.02-". The train and predict functions are matlab mex files and can not be opened or edited. Can anyone give me a piece of advice on what to do or is there a valid and completely matlab-based version of random forests.
I've read the randomforest-matlab carefully. The main training part unfortunately is a dll file. Through reading more, most of my wonders is now resolved. My question mainly was how to run several trees simultaneously.
Have you taken a look at these libraries?
Stochastic Bosque
randomforest-matlab
If you're doing a research project on it, the best thing is probably to implement the individual tree training yourself in C and then write Mex wrappers. I'd start with an ID3 tree (before attempting C4.5 for instance.) Then write the random forest code itself, which, once you write the tree code, isn't all that hard.
You'll:
learn a lot
be able to modify them as much as you like
eventually move on to exploring new areas with them
I've implemented them myself from scratch so I can help once you post some of your own code. But I don't think anybody on this site will write the code for you.
Will it take effort? Yes. Will you come out of it with more knowledge and ability than you had going in? Undoubtably.
There is a nice library in R called randomForest. It is based on the original implementation of Breiman in Fortran but it is now mainly recoded in C.
http://cran.r-project.org/web/packages/randomForest/index.html
The main parameters you talk about (tree depth, number of features to be tested, ...) are directly available.
Another library I would recommend is Weka. It is java based and lucid.Performance is slightly off though compared to R. The source code can be downloaded from http://www.cs.waikato.ac.nz/ml/weka/