FloatingArrayDesign · sanguinariojoe · Jun 9, 2026 · Feb 27, 2026 · Mar 2, 2026 · Mar 2, 2026
diff --git a/.github/workflows/matlab.yml b/.github/workflows/matlab.yml
@@ -42,10 +42,10 @@ jobs:
         run: cmake --install ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
 
       - name: Set up MATLAB
-        uses: matlab-actions/setup-matlab@v2
+        uses: matlab-actions/setup-matlab@v3
 
       - name: Compile and run
-        uses: matlab-actions/run-command@v2
+        uses: matlab-actions/run-command@v3
         with:
           command: |
               mex('-setup', '-v', 'C');

diff --git a/.github/workflows/memcheck.yml b/.github/workflows/memcheck.yml
@@ -36,4 +36,4 @@ jobs:
     - name: Test
       working-directory: ${{github.workspace}}/build
       # We are just testing in Linux
-      run: ctest -C ${{env.BUILD_TYPE}} -T memcheck --output-on-failure -j ${{env.PROCESSES}} -E "(seafloor|time_schemes|wavekin|wilson|lowe_and_langley_2006)"
+      run: ctest -C ${{env.BUILD_TYPE}} -T memcheck --output-on-failure -j ${{env.PROCESSES}} -E "(seafloor|time_schemes|wavekin|wilson|lowe_and_langley_2006|syrope)"
diff --git a/.github/workflows/python-wheels-emulated.yml b/.github/workflows/python-wheels-emulated.yml
@@ -69,17 +69,17 @@ jobs:
             mkdir -p ${{github.workspace}}/install
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
+        uses: docker/setup-qemu-action@v4
         with:
           platforms: all
         if: runner.os == 'Linux'
 
       - name: Build wheels
-        uses: pypa/cibuildwheel@v3.3.1
+        uses: pypa/cibuildwheel@v3.4.1
         with:
             output-dir: dist
 
-      - uses: actions/upload-artifact@v6
+      - uses: actions/upload-artifact@v7
         id: build_wheels
         with:
           name: python-wheels-${{runner.os}}_${{inputs.arch}}

diff --git a/.github/workflows/python-wheels-test.yml b/.github/workflows/python-wheels-test.yml
@@ -31,7 +31,7 @@ jobs:
           python-version: '3.12' 
 
       - name: Download the wheels
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           path: dist/
           pattern: python-wheels-${{runner.os}}_${{inputs.arch}}*

diff --git a/.github/workflows/python-wheels.yml b/.github/workflows/python-wheels.yml
@@ -36,7 +36,7 @@ jobs:
             python -m pip install -U pip setuptools
             python setup.py sdist
 
-      - uses: actions/upload-artifact@v6
+      - uses: actions/upload-artifact@v7
         id: build_wheels
         with:
           name: python-wheels-sdist
@@ -136,7 +136,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: Download artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           path: dist/
           pattern: python-wheels-*

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,37 @@
+## [2.7.0] - 2026-06-09
+
+### 🚀 Features
+
+- *(core)* Implementation of the Syrope model for polyester ropes
+- *(core)* [**breaking**] Line breaking utilities (#379)
+
+### 🐛 Bug Fixes
+
+- *(core)* Memory leak on lean-vtk
+- *(core)* Segmentation Fault when trying to print Td output
+- *(core)* Return an error code when points below the seabed are detected
+- *(core)* Demote points below seabed from error to warning
+- *(core)* MATLAB wrappers trying to use the instance as a parameter (fixes #384)
+
+### 💼 Other
+
+- *(deps)* Bump actions/upload-artifact from 6 to 7
+- *(deps)* Bump actions/download-artifact from 7 to 8
+- *(deps)* Bump docker/setup-qemu-action from 3 to 4
+- *(deps)* Bump pypa/cibuildwheel from 3.3.1 to 3.4.0
+- *(deps)* Bump pypa/cibuildwheel from 3.4.0 to 3.4.1
+- *(deps)* Bump matlab-actions/run-command from 2 to 3
+- *(deps)* Bump matlab-actions/setup-matlab from 2 to 3
+## [2.6.1] - 2026-02-20
+
+### 🐛 Bug Fixes
+
+- *(core)* Save with VTP extension
+- *(core)* Wrong Fortran indexes
+
+### ⚙️ Miscellaneous Tasks
+
+- *(doc)* Moved to git-cliff to produce the CHANGELOG file
 ## [2.6.0] - 2026-02-17
 
 ### 🚀 Features

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.10)
 set(MOORDYN_MAJOR_VERSION 2)
-set(MOORDYN_MINOR_VERSION 6)
-set(MOORDYN_PATCH_VERSION 1)
+set(MOORDYN_MINOR_VERSION 7)
+set(MOORDYN_PATCH_VERSION 0)
 set(MOORDYN_VERSION ${MOORDYN_MAJOR_VERSION}.${MOORDYN_MINOR_VERSION})
 project(Moordyn VERSION ${MOORDYN_VERSION})
 

diff --git a/docs/inputs.rst b/docs/inputs.rst
@@ -266,6 +266,7 @@ There is not a limit on the number of lines you can write here.
  --------------------- MoorDyn Input File ------------------------------------
  MoorDyn v2 sample input file
 
+.. _line-types-v2:
 Line Types
 ^^^^^^^^^^
 
@@ -285,7 +286,7 @@ The columns in order are as follows:
  - Diam –  the volume-equivalent diameter of the line – the diameter of a cylinder having the same 
    displacement per unit length (m)
  - MassDen –  the mass per unit length of the line (kg/m)
- - EA – the line stiffness, product of elasticity modulus and cross-sectional area (N)
+ - EA – the line stiffness, product of elasticity modulus and cross-sectional area (N), or nonlinear parameters (see descriptions below)
  - BA/-zeta –  the line internal damping (measured in N-s) or, if a negative value is entered, the 
    desired damping ratio (in fraction of critical) for the line type (and MoorDyn will set the BA 
    of each line accordingly)
@@ -306,24 +307,13 @@ The columns in order are as follows:
  - cF - OPTIONAL - the center of the range of non-dimensional frequencies for the CF VIV synchronization model. If it is not
    provided and VIV is enabled (Cl > 0) then it is default to 0.18 to align with the the theory found :ref:`here <version2>`
 
-Note: Non-linear values for the stiffness (EA) are an option in MoorDyn. For this, a file name can be provided instead of a number. This file 
-must be located in the same folder as the main MoorDyn input file for MoorDyn-C or for MoorDyn-F 
-in the same folder as the executable calling MoorDyn-F, unless a path is specified. Such file is a 
-tabulated file with 3 header lines and then a strain column and a tension column separated by a blank space:
-
-.. code-block:: none
-
-  ----Polyester----
-  Strain    Tension
-  (-)       (N)
-  0.0       0.0
-  ...       ...
-
 Note: MoorDyn has the ability to model the viscoelastic properties of synthetic lines in two ways. The first method, from work linked in the 
 :ref:`theory section <theory>`, allows a user to specify a bar-separated constant dynamic and static stiffness. The second method allows the user 
 to provide a constant static stiffness and two terms to determine the dynamic stiffness as a linear function of mean load. The equation is:
-`EA_d = EA_Dc + EA_D_Lm * mean_load` where `EA_D_Lm` is the slope of the load-stiffness curve. Both of these methods allow users to provide static 
-and dynamic damping coefficients as values separated by |. While the static damping can be described as a fraction of critical, the dynamic damping 
+`EA_d = EA_Dc + EA_D_Lm * mean_load` where `EA_D_Lm` is the slope of the load-stiffness curve. This method can be used standalone, 
+and is also part of the Syrope model described in :ref:`Syrope Model for Polyester Lines <syrope-model-polyester-lines>`. 
+Both of these methods allow users to provide static and dynamic damping coefficients as values separated by |. 
+While the static damping can be described as a fraction of critical, the dynamic damping 
 needs to be input as a value. Example inputs are below: 
 
 .. code-block:: none
@@ -497,9 +487,9 @@ The columns are as follows:
  - UnstrLen - the unstretched length of the line
  - NumSegs - how many segments the line is discretized into (it will have NumSegs+1 nodes total, 
    including its two end nodes)
- - LineOutputs - any data to be output in a dedicated output file for that line. 
+ - LineOutputs - any data to be output in a dedicated output file for that line.
 
-This last entry expects a string of one or more characters without spaces, each character 
+This `LineOutputs` entry expects a string of one or more characters without spaces, each character 
 activating a given output property. A placeholder character such as “-” should be used if no 
 outputs are wanted. Ten output properties are currently possible:
 
@@ -1008,6 +998,80 @@ data.
  5000            0.15         0.0
  --------------------- need this line ------------------
 
+Nonlinear Stiffness (EA) Inputs
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Non-linear values for the stiffness (EA) are an option in MoorDyn. For this, a file name can be provided instead of a number. This file 
+must be located in the same folder as the main MoorDyn input file for MoorDyn-C or for MoorDyn-F 
+in the same folder as the executable calling MoorDyn-F, unless a path is specified. Such file is a 
+tabulated file with 3 header lines and then a strain column and a tension column separated by a blank space:
+
+.. code-block:: none
+
+  ----Polyester----
+  Strain    Tension
+  (-)       (N)
+  0.0       0.0
+  ...       ...
+
+.. _syrope-model-polyester-lines:
+Syrope Model for Polyester Lines
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+MoorDyn supports the Syrope material model for polyester ropes. In this formulation, the
+tension–strain response is nonlinear and load-path dependent, meaning the unloading and
+reloading curves differ. See additional details in the :ref:`theory section <theory>`
+and the references therein.
+
+To enable the Syrope model for a given line type, specify the EA field using three
+bar-separated entries, analogous to the load-dependent dynamic stiffness method described in :ref:`Line Types <line-types-v2>`.
+To indicate Syrope, the first entry must start with ``SYROPE:``, followed by the name (or path)
+of a Syrope config file defining the working curves. The second and third entries are
+``EA_Dc`` and ``EA_D_Lm`` (as in the load-dependent dynamic stiffness method in :ref:`Line Types <line-types-v2>`). Static and dynamic
+damping may be provided in BA as ``BA_s|BA_d`` (same convention as above).
+
+Example:
+
+.. code-block:: none
+
+  TypeName   Diam    Mass/m     EA                                 BA
+  (name)     (m)     (kg/m)     (N)                               (N-s)
+  poly       ...     ...        SYROPE:syrope.dat|EA_Dc|EA_D_Lm   BA_s|BA_d
+
+The file ``syrope.dat`` defines 
+
+- OWC: a tabulated nonlinear original working curve
+- WCType: the working-curve type (options: ``LINEAR``, ``QUADRATIC``, ``EXP``)
+- k1: the first coefficient for the working curve formula (sets the strain offset where mean tension is zero)
+- k2: the second coefficient for the working curve formula (sets the curve shape)
+
+One example of such file is shown below.
+
+.. code-block:: none
+
+  ../owc.dat  OWC     Original working curve lookup table path, relative to the MoorDyn input file
+  LINEAR      WCType  Working curve formula: LINEAR, QUADRATIC, or EXP
+  0.25        k1      First parameter defining the working curve shape
+  1.00        k2      Second parameter defining the working curve shape
+
+The ``owc.dat`` file follows the same format as the tabulated non-linear stiffness files described
+above (three header lines, then columns for strain and tension).
+
+Initial conditions are specified for the Syrope lines in a separate ``SYROPE IC`` section placed after the ``LINES`` section.
+
+- Line(s) - the Syrope line number(s). This may be a single line number or a comma-separated list of line numbers. If non-Syrope lines are included, they are ignored and a warning is raised.
+- Tmax0 – the initial highest mean tension experienced by the line prior to the current time (N)
+- Tmean0 – the initial mean tension (N)
+
+One example of the ``SYROPE IC`` section is shown below.
+
+.. code-block:: none
+
+  ---------------------- SYROPE IC --------------------------------------
+  Line(s)   Tmax0    Tmean0
+  (-)        (N)       (N)
+  7,8,9    3.53e6    1.18e6
+
+In general, ``Tmax0 >= Tmean0``.
+
 MoorDyn-F with FAST.Farm - Inputs
 -------------------------------
 

diff --git a/docs/references.rst b/docs/references.rst
@@ -82,16 +82,16 @@ Overview of MoorDyn v2 (bodies, rods, and line failures):
   `Hall, Matthew, “MoorDyn V2: New Capabilities in Mooring System Components and Load Cases.” In Proceedings of the ASME 2020 39th International 
   Conference on Ocean, Offshore and Arctic Engineering. virtual conference, 2020. <https://www.nrel.gov/docs/fy20osti/76555.pdf>`_
 
-Seabed friction and bathymetry approach used in v2:
-
-  `Housner, Stein, Ericka Lozon, Bruce Martin, Dorian Brefort, and Matthew Hall, “Seabed Bathymetry and Friction Modeling in MoorDyn.” Journal of 
-  Physics: Conference Series 2362, no. 1, Nov 2022: 012018. <https://doi.org/10.1088/1742-6596/2362/1/012018>`_
-
 Implementation of bending stiffness modeling for power cables:
 
   `Hall, Matthew, Senu Sirnivas, and Yi-Hsiang Yu, “Implementation and Verification of Cable Bending Stiffness in MoorDyn.” In ASME 2021 3rd International Offshore Wind 
   Technical Conference, V001T01A011. Virtual, Online: American Society of Mechanical Engineers, 2021. <https://doi.org/10.1115/IOWTC2021-3565>`_
 
+Seabed friction and bathymetry approach used in v2:
+
+  `Housner, Stein, Ericka Lozon, Bruce Martin, Dorian Brefort, and Matthew Hall, “Seabed Bathymetry and Friction Modeling in MoorDyn.” Journal of 
+  Physics: Conference Series 2362, no. 1, Nov 2022: 012018. <https://doi.org/10.1088/1742-6596/2362/1/012018>`_
+
 Non-linear line stiffness:
 
  `Lozon, Ericka, Matthew Hall, Paul McEvoy, Seojin Kim, and Bradley Ling, “Design and Analysis of a Floating-Wind Shallow-Water Mooring System 
@@ -122,6 +122,10 @@ Modeling of Bi-stable Nonlinear Energy Sinks in MoorDyn (most recent description
   `Anargyros Michaloliakos, Wei-Ying Wong, Ryan Davies, Malakonda Reddy Lekkala, Matthew Hall, Lei Zuo, Alexander F. Vakakis, "Stabilizing dynamic subsea power cables using 
   Bi-stable nonlinear energy sinks", Ocean Engineering, vol. 334, August 2025. <https://doi.org/10.1016/j.oceaneng.2025.121613>`_
 
+Syrope model for polyester ropes:
+
+  `Wei, Zhilong, Harry B. Bingham, and Yanlin Shao. 2026. “ESOMOOR D5.1: Extended Moordyn Solver and Validation Report”. Technical University of Denmark. <https://doi.org/10.11583/DTU.31408806>`_
+
 The Fortran version of MoorDyn is available as a module inside of OpenFAST:
 
   https://openfast.readthedocs.io/en/main/

diff --git a/source/IO.cpp b/source/IO.cpp
@@ -278,11 +278,6 @@ IO::LoadFile(const std::string filepath) const
 	uint8_t major, minor;
 	f.read((char*)&major, sizeof(uint8_t));
 	f.read((char*)&minor, sizeof(uint8_t));
-	std::cout << major << std::endl;
-	std::cout << minor << std::endl;
-	std::cout << _min_major_version << std::endl;
-	std::cout << _min_minor_version << std::endl;
-	std::cout << "number=" << 7 << std::endl;
 	if ((major < _min_major_version) ||
 	    ((major == _min_major_version) && (minor < _min_minor_version))) {
 		LOGERR << "The file '" << filepath << "' was written by MoorDyn "