added input-constrained iLQR files

Author: e-duar-do

.gitignore

@@ -1,3 +1,6 @@
+# Build directory
+build/
+
 # Prerequisites
 *.d
 

CMakeLists.txt

@@ -0,0 +1,40 @@
+cmake_minimum_required(VERSION 3.11)
+
+project(constrained-ilqr VERSION 0.1.0)
+
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+include(FetchContent)
+FetchContent_Declare(
+  eigen3
+  GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
+  GIT_TAG 3.4.0
+  GIT_SHALLOW TRUE
+  GIT_PROGRESS TRUE
+)
+FetchContent_Declare(
+    projected-descent
+    GIT_REPOSITORY https://github.com/JuDO-dev/projected-descent.git
+    GIT_TAG main
+    GIT_SHALLOW TRUE
+    GIT_PROGRESS TRUE
+)
+FetchContent_MakeAvailable(eigen3 projected-descent)
+
+add_library(constrained_ilqr INTERFACE)
+target_include_directories(constrained_ilqr INTERFACE
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<INSTALL_INTERFACE:include>
+)
+
+target_link_libraries(constrained_ilqr INTERFACE
+  Eigen3::Eigen
+  projected_descent
+)
+
+option(BUILD_TESTS "Build tests" ON)
+if(BUILD_TESTS)
+    enable_testing()
+    add_subdirectory(tests)
+endif()

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Eduardo M. G. Vila
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.