MoorDyn
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mattEhall
MATLAB API
Hi,
I am really struggling to get MATLAB to talk to moordyn, is there any chance a document with more in detail set up process and API can be added?
Many thanks
I first tried to compile the software on mac and it produced the errors:
make clang++ -c -Ofast -g -w -Wall -static -static-libgcc -static-libstdc++ -std=gnu++0x -DMoorDyn_EXPORTS -DOSX ../MoorDyn.cpp In file included from ../MoorDyn.cpp:20: ../MoorDyn.h:41:5: error: unknown type name 'dllexport' int DECLDIR LinesInit(double X[], double XD[]); ^ ../MoorDyn.h:22:30: note: expanded from macro 'DECLDIR' #define DECLDIR __declspec(dllexport) ^ ../MoorDyn.h:41:13: error: expected function body after function declarator int DECLDIR LinesInit(double X[], double XD[]); ^ ../MoorDyn.h:43:5: error: unknown type name 'dllexport' int DECLDIR LinesCalc(double X[], double XD[], double Flines[], double* , double* ); ^ ../MoorDyn.h:22:30: note: expanded from macro 'DECLDIR' #define DECLDIR __declspec(dllexport) ^ ../MoorDyn.h:43:13: error: expected function body after function declarator int DECLDIR LinesCalc(double X[], double XD[], double Flines[], double* , double* ); ^ ../MoorDyn.h:45:5: error: unknown type name 'dllexport' int DECLDIR FairleadsCalc2(double rFairIn[], double rdFairIn[], double fFairIn[], double* t_in, double *dt_in); // easier to call version
I then switched over to windows operating system using the already pre-compiled .dll file but I could not get MATLAB to load in the library. The API I tried to use is from the manual: http://www.matt-hall.ca/files/MoorDyn%20Users%20Guide%202017-08-16.pdf
%% Setup X = zeros(6,1); % platform position XD = zeros(6,1); % platform velocity N = 10; % number of coupling time steps dt = 0.5; % coupling time step size (time between MoorDyn calls) Ts = zeros(N,1); % time step array FairTens1 = zeros(N+1,1); % array for storing fairlead 1 tension time series FLines_temp = zeros(1,6); % going to make a pointer so LinesCalc can modify FLines FLines_p = libpointer('doublePtr',FLines_temp); % access returned value with FLines_p.value %% Initialization loadlibrary('Lines','MoorDyn'); % load MoorDyn DLL calllib('Lines','LinesInit',X,XD) % initialize MoorDyn
%% Simulation XD(1) = 0.1; % give platform 0.1 m/s velocity in surge for i=1:N calllib('Lines', 'LinesCalc', X, XD, FLines_p, Ts(i), dt); % some MoorDyn time stepping FairTens1(i+1) = calllib('Lines','GetFairTen',1); % store fairlead 1 tension X = X + XDdt; % update position Ts(i+1) = dti; % store time end
%% Ending calllib('Lines','LinesClose'); % close MoorDyn unloadlibrary Lines; % unload library (never forget to do this!)
The error I get for MATLAB is:
Error using loadlibrary Failed to preprocess the input file. Output from preprocessor is:cc1.exe: fatal error: C: ...\MoorDyn: No such file or directory compilation terminated.
Error in MoorDyn_API (line 11) loadlibrary('Lines','MoorDyn'); % load MoorDyn DLL
Partially Solved:
loadlibrary('Lines','MoorDyn'); % load MoorDyn DLL
has been changed to:
loadlibrary('Lines','MoorDyn.h'); % load MoorDyn DLL
The compiled library from the WEC-SIM has been used to work with MAC OS: https://github.com/WEC-Sim/MoorDyn
This utilises the compiled Lines.dylib
The software will now load into MATLAB but issues arise for the two lines:
X = X + XDdt; % update position Ts(i+1) = dti; % store time
Hi @TGiles1998
I am trying to access MoorDyn through MATLAB in Windows in a similar way, and I am receiving similar error messages about libraries not being loaded. I looked at your proposed solutions, but I still cannot get the software to work due to missing libraries. I think the problem is in the file setup in my working folder, could you please share the files you are using and the folder structure?
Many thanks for your help!
Hi @daankoetzier
For windows I also then changed
loadlibrary('Lines','MoorDyn.h'); % load MoorDyn DLL
to
loadlibrary('Lines.dll','MoorDyn.h'); % load MoorDyn DLL
adding the .dll
My folder structure is as follows:
-Overall Folder:
- Lines.dll
- Matlab_API_commands.m
- mooring (another folder)
- lines.txt
Hope this helps!
Hi @TGiles1998 where did find the lines.dll file. I could not find it in the downloaded Moordyn-dev folder
Hi, You have to either compile the software yourself from the make file in the repo or alternatively you can access it in its already compiled version that is part of the WEC-SIM. Link here: https://github.com/WEC-Sim/moorDyn
Download these from the WEC-SIM repo using the link and setup the folder as previously mentioned and it should work.
Hope this helps!
I've opened a pull request so that these files can be more easily found from the main repo. https://github.com/mattEhall/MoorDyn/pull/17#issue-1155927336 Thanks, Thomas
@TGiles1998 Thanks for answering. Another question that I have is how to set up my own input file properly. I copied the example lines.txt from WEC_SIM/moorDyn and modified the parameters. If I want to run the simulation with new input file. Should I just replace the line.txt file with the modified one? Because I did not see anywhere in the example code that is trying to open up any txt file
@hwen42
Yes just change the line.txt file with your modified one. The compiled dynamic library will just pick this up and run it through the C++.
@TGiles1998 Thanks for answering. I downloaded the WEC_Sim-master folder and tried to run the example. It works. But the only lines.txt file that I found is in RM3_CoupledWithMoorDyn folder. If I have to replace with my own input txt file. Should I just replace it in that directory? Or should I make a new morring folder and put it there,
This is the Input file that I have: Mooring line data file for MoorDyn in Lines.dll ---------------------- LINE DICTIONARY ----------------------------------------------------- LineType Diam MassDenInAir EA BA/-zeta Can Cat Cdn Cdt (-) (m) (kg/m) (N) (Pa-s/-) (-) (-) (-) (-) chain 8e-3 1.1 7.5E+6 0 0 0 2.4 1.15 ---------------------- NODE PROPERTIES ----------------------------------------------------- Node Type X Y Z M V FX FY FZ CdA CA (-) (-) (m) (m) (m) (kg) (m^3) (kN) (kN) (kN) (m^2) (-) 1 Fix 0 0 0 0 0 0 0 0 0 0 2 Vessel 5 0 -8.6603 0 0 0 0 0 0 0
---------------------- LINE PROPERTIES ----------------------------------------------------- Line LineType UnstrLen NumSegs NodeAnch NodeFair Flags/Outputs (-) (-) (m) (-) (-) (-) (-) 1 chain 10 5 1 2 tp ---------------------- SOLVER OPTIONS----------------------------------------- 0.001 dtM - time step to use in mooring integration 0 WaveKin - wave kinematics flag (0=neglect, the only option currently supported) 70 WtrDpth - water depth 5.0 CdScaleIC - factor by which to scale drag coefficients during dynamic relaxation IC gen 0.001 threshIC - threshold for IC con -------------------------- OUTPUTS -------------------------------- FairTen1 Con1px Con1py Con1pz Con2px Con2py Con2pz --------------------- need this line ------------------
Is there a blank line above the "LINE PROPERTIES" line? If so, that could be the problem.
@mattEhall Hello Matt, there is actually no line above the "Line Properties" (It just looks like that when I copy pasted.) I am just trying to simulate a simple problem where one end is fixed and one end is free to move. Therefore I only need 2 node. But when I used the example Matlab code. I can't generate any results while I can generate result using the example provided (the one with 6 nodes). My question is do I have to modify the dll file in the functions/moordyn folder?
The v2 candidate has a Matlab wrapper, based on mex files, which is blazzing. Unfortunately, it is totally impossible to build that wrapper automatically in a github action, so no binaries will be provided. That means you have to compile MoorDyn by yourself to get Matllab support. The process is documented here
An example of a Matlab script can be found here
P.S. You are welcome to support this v2 candidate in the same PR link:
So it will be merged ASAP. You can also leave your feedback
