Linux support

.github/workflows/ci.yml

@@ -0,0 +1,40 @@
+name: ci
+
+on:
+  pull_request:
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    name: build-${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+          - macOS-latest
+          - windows-latest
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@v4
+
+      - name: Setup Pixi
+        uses: prefix-dev/[email protected]
+        with:
+          manifest-path: pixi.toml
+
+      - name: Setup gfortran
+        uses: fortran-lang/setup-fortran@v1
+        with:
+          compiler: gcc
+
+      - name: Build GFLOW executable
+        run: pixi run build-release-gfortran
+
+      - name: Run Tests
+        run: pixi run test

.gitignore

@@ -36,4 +36,9 @@
 *.egg-info
 
 # Visual Studio Code
-.vscode/settings.json
+.vscode/settings.json
+
+# Python byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class

.vscode/launch.json

@@ -5,10 +5,10 @@
             "name": "Debug (gdb)",
             "type": "cppdbg",
             "request": "launch",
-            "program": "${workspaceFolder}/builddir/gflow2.exe",
-            "args": ["test8.dat"],
+            "program": "${workspaceFolder}/builddir-debug-gfortran/gflow2.exe",
+            "args": ["well_uflow.dat"],
             "stopAtEntry": false,
-            "cwd": "c:/tmp/gflow/test8",
+            "cwd": "${workspaceFolder}/test/data",
             "environment": [],
             "externalConsole": false,
             "MIMode": "gdb",

.vscode/tasks.json

@@ -0,0 +1,37 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Build Release (gfortran)",
+            "type": "shell",
+            "command": "pixi",
+            "args": ["run", "build-release-gfortran"],
+            "group": "build",
+            "problemMatcher": ["$gcc"]
+        },
+        {
+            "label": "Build Debug (gfortran)",
+            "type": "shell",
+            "command": "pixi",
+            "args": ["run", "build-debug-gfortran"],
+            "group": "build",
+            "problemMatcher": ["$gcc"]
+        },
+        {
+            "label": "Build Release (ifort)",
+            "type": "shell",
+            "command": "pixi",
+            "args": ["run", "build-release-ifort"],
+            "group": "build",
+            "problemMatcher": ["$msCompile"]
+        },
+        {
+            "label": "Build Debug (ifort)",
+            "type": "shell",
+            "command": "pixi",
+            "args": ["run", "build-debug-ifort"],
+            "group": "build",
+            "problemMatcher": ["$msCompile"]
+        }
+    ]
+}

DEVELOPER.md

@@ -105,17 +105,103 @@ git remote add upstream https://github.com/MODFLOW-USGS/modflow6.git
 [Meson](https://mesonbuild.com/index.html) is the recommended build system for
 GFLOW. It is included in the provided pixi environment.
 
-Building GFLOW requires two steps:
-
-- configure the build directory
-- build the project
-
 We can use pixi to do so:
 
 ```shell
-pixi run setup
+pixi run build-release-gfortran
 ```
 
-```shell
-pixi run build
+We can also build from VSCode:
+Press `Cntrl + Shift + P > Tasks: Run build task > Build Release (gfortran)`.
+
+## Deubugging
+
+Most of the time you will want to debug with `gdb`. When compiling with `ifort`
+on Windows, `vsdbg` is preferred.
+
+*Windows*
+
+`gdb` can be used with Gfortran, and is included in the MINGW installation.
+
+*Linux*
+
+Run: `apt install gdb`.
+
+*macOS*
+
+Run: `brew install gdb`.
+
+## Debugging Linux on Windows via WSL
+
+Linux applications can be relatively easily set up and run on Windows thanks to
+Windows Subsystem for Linux (WSL).
+
+### Setting up WSL
+
+1. Start by [installing WSL](https://learn.microsoft.com/en-us/windows/wsl/install).
+2. Start WSL and install a latest version of Ubuntu: `wsl --install -d Ubuntu-22.04`
+3. You'll be asked for a username and pasword. This password is required for
+   `sudo` operations. (Store username and pass word in your password manager.)
+4. Install `pixi`: `curl -fsSL https://pixi.sh/install.sh | bash`
+5. Install `git`, `gfortran`, and `gdb`. This is much more straightforward than
+   on Windows, run: `sudo apt update` followed by `sudo apt install git gfortran gdb`.
+6. Clone your fork to the WSL workspace:
+  `git clone [email protected]:<github username>/gflow1.git`
+
+### Get your VSCode ready
+
+1. Open VSCode (in Windows).
+2. Install the WSL extension in VSCode.
+3. Click the green `><` icon in the lower left corner.
+4. You may have multiple WSL distributions. Choose the appropriate one.
+5. Install the C++ extension (debugging) and the Modern Fortran (syntax
+   highlighting) extension in the WSL VSCode.
+
+### Debugging
+
+1. Start WSL.
+2. Open VSCode.
+3. Click the green `><` icon in the lower left corner.
+4. You may have multiple WSL distributions. Choose the appropriate one.
+5. Open an existing folder: `File > Open Folder`; choose the `gflow1` directory.
+6. Press ``Cntrl + ` `` to open the VSCode terminal, and choose TERMINAL.
+7. Press `Cntrl + Shift + P > Tasks: Run build task > Build Debug (gfortran)`;
+   alternatively run `pixi build-debug-gfortran` from the command line.
+8. Set the `program`, `miDebuggerPath`, `cwd`, and `args` entries to their
+   appropriate values.
+9. Place a breakpoint somewhere, and start the debugger from the VSCode menu on
+   the left or via `Cntrl + Shift + D`. Choose `Debug (gdb)`.
+
+By and large, the same `launch.json` can be used as you would use on Windows.
+This is the `launch.json` to debug one of the simple test examples:
+
+```json
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Debug (gdb)",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${workspaceFolder}/builddir/gflow2",
+            "args": ["well_uflow.dat"],
+            "stopAtEntry": false,
+            "cwd": "${workspaceFolder}/test/data",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "miDebuggerPath": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                }
+            ],
+        }
+    ]
+}
 ```
+
+Note: the `program` and `miDebuggerPath` entries are without an `.exe`
+extension as they would be on Windows.