Constraint aliasing

.github/workflows/dymos_tests_workflow.yml

@@ -12,7 +12,6 @@ on:
   pull_request:
     branches: [ master ]
   workflow_dispatch:
-    branches: [ master ]
 
 jobs:
 

docs/dymos_book/faq/use_partial_coloring.ipynb

@@ -4,6 +4,7 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
+    "scrolled": true,
     "tags": [
      "active-ipynb",
      "remove-input",
@@ -65,6 +66,7 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
+    "scrolled": true,
     "tags": [
      "remove-input"
     ]
@@ -161,6 +163,7 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
+    "scrolled": true,
     "tags": [
      "remove-input",
      "remove-output"
@@ -203,6 +206,7 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
+    "scrolled": true,
     "tags": [
      "remove-input",
      "hide-output"
@@ -216,7 +220,9 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {},
+   "metadata": {
+    "scrolled": false
+   },
    "outputs": [],
    "source": [
     "import os \n",
@@ -244,9 +250,14 @@
     "\n",
     "        p.driver = om.pyOptSparseDriver()\n",
     "        p.driver.options['optimizer'] = 'IPOPT'\n",
-    "        p.driver.declare_coloring(tol=1.0E-12)\n",
     "        p.driver.opt_settings['max_iter'] = 500\n",
     "        p.driver.opt_settings['alpha_for_y'] = 'safer-min-dual-infeas'\n",
+    "        p.driver.opt_settings['print_level'] = 5\n",
+    "        p.driver.opt_settings['nlp_scaling_method'] = 'gradient-based'\n",
+    "        p.driver.opt_settings['tol'] = 1.0E-7\n",
+    "        p.driver.opt_settings['mu_strategy'] = 'monotone'\n",
+    "        \n",
+    "        p.driver.declare_coloring(tol=1.0E-12)\n",
     "\n",
     "        #\n",
     "        # Instantiate the trajectory and phase\n",
@@ -350,6 +361,7 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
+    "scrolled": true,
     "tags": [
      "remove-input",
      "remove-output"
@@ -398,7 +410,7 @@
    }
   },
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -412,7 +424,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.9.7"
   }
  },
  "nbformat": 4,

docs/dymos_book/features/phases/constraints.ipynb

@@ -43,6 +43,13 @@
     "                           'please install them and restart this notebook\\'s runtime: {\",\".join(missing_packages)}')"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -132,9 +139,30 @@
     "``` \n",
     "\n",
     "Phases also support the `add_path_constraint` method, which imposes path constraints as constraints in the NLP problem.\n",
-    "As with `add_bound_constraint`, the `add_path_constraint` method is the only option for path constraining an output of the ODE.\n",
+    "As with `add_boundary_constraint`, the `add_path_constraint` method is the only option for path constraining an output of the ODE.\n",
+    "\n",
+    "The downside of path constraints is that they add a considerable number of constraints to the NLP problem and thus may negatively impact performance, although this is generally minor for many problems.\n",
+    "\n",
+    "## Implementation Detail - Constraint Aliasing\n",
+    "\n",
+    "As of OpenMDAO Version 3.17.0, multiple constraints are allowed to exist on the same output as long as they use different indices and are provided different aliases.\n",
+    "In Dymos, this allows us to always apply multiple constraints (initial, final, or path constraints) to the timeseries outputs of the phase.\n",
+    "To allow boundary and path constraints to potentially be applied to the same timeseries outputs, they are provided the following aliases:\n",
+    "\n",
+    "An initial boundary constraint on the name `'alpha'` will be given the alias `f'{path_to_phase}.initial_boundary_constraints->alpha`.  \n",
+    "\n",
+    "A final boundary constraint on the name `'alpha'` will be given the alias `f'{path_to_phase}.final_boundary_constraints->alpha`.\n",
+    "\n",
+    "A path constraint on the name `'alpha'` will be given the alias `f'{path_to_phase}.path_constraints->alpha`.  \n",
+    "\n",
+    "The use of the `->` in this case is intended to remind the user that this is not the actual path to the variable being constrained.\n",
+    "\n",
+    "## Constraint Linearity\n",
     "\n",
-    "The downside of path constraints is that they add a considerable number of constraints to the NLP problem and thus may negatively impact performance, although this is generally minor for many problems.\n"
+    "OpenMDAO will treat all boundary and path consraints as nonlinear unless the user provides the argument `linear=True` to `add_boundary_constraint` or `add_path_constraint`.\n",
+    "Note that it is the responsibility of the user to understand the inner workings of Dymos and their model well enough to know if the constraint may be treated as linear.\n",
+    "Specifying an output that is actually a nonlinear function of the design variables as a linear constraint will almost certainly result of the failure of the optimization due to incorrect derivatives.\n",
+    "The derivatives of linear constraints are computed once and cached by OpenMDAO for the remainder of the optimization.\n"
    ]
   }
  ],
@@ -148,7 +176,7 @@
    }
   },
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -162,7 +190,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.1"
+   "version": "3.9.7"
   }
  },
  "nbformat": 4,

dymos/examples/brachistochrone/test/ex_brachistochrone.py

@@ -34,8 +34,6 @@ def brachistochrone_min_time(transcription='gauss-lobatto', num_segments=8, tran
     p.model.add_subsystem('traj0', traj)
     traj.add_phase('phase0', phase)
 
-    # p.model.add_subsystem('traj0', traj)
-
     phase.set_time_options(fix_initial=True, duration_bounds=(.5, 10))
 
     phase.add_state('x', fix_initial=True, fix_final=False, solve_segments=solve_segments)
@@ -81,6 +79,6 @@ def brachistochrone_min_time(transcription='gauss-lobatto', num_segments=8, tran
 
 
 if __name__ == '__main__':
-    p = brachistochrone_min_time(transcription='radau-ps', num_segments=3, run_driver=True,
+    p = brachistochrone_min_time(transcription='radau-ps', num_segments=20, run_driver=True,
                                  transcription_order=5, compressed=False, optimizer='SNOPT',
                                  solve_segments=False, force_alloc_complex=True)