Solvned project from 2020

Note that Go didn't have generics back then.

1 files changed, 77 insertions, 0 deletions

diff --git a/examples/hooke.go b/examples/hooke.go
new file mode 100644
index 0000000..36229c1
--- /dev/null
+++ b/examples/hooke.go
@@ -0,0 +1,77 @@
+// Example visualization of Hooke's law.
+//
+// Copyright (C) 2020 Juan Marín Noguera
+//
+// This file is part of Solvned.
+//
+// Solvned is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Lesser General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option) any 
+// later version.
+//
+// Solvned is distributed in the hope that it will be useful, but WITHOUT ANY 
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+// A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with Solvned. If not, see <https://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"fmt"
+	"github.com/Arafatk/glot"
+	"mned"
+	"mned/ivp"
+	"mned/method"
+)
+
+func spring1(speed float64) {
+	spring := ivp.HookeSpring{
+		Mass:       1,
+		Spring:     1.5,
+		Length:     0.7,
+		Friction:   0.3,
+		Amplitude:  0.4,
+		AngleSpeed: speed,
+	}
+	problem := spring.ToIVP()
+	plot, err := glot.NewPlot(2, true, false)
+	if err != nil {
+		fmt.Printf("Creating the plot: %v\n", err)
+		return
+	}
+	if err := plot.SetXLabel(
+		fmt.Sprintf("Time (s) -- w = %v", speed),
+	); err != nil {
+		fmt.Printf("Drawing the X label: %v\n", err)
+		return
+	}
+
+	solution, _ := mned.DenseSolve(
+		method.RKFehlberg(0.0001, 0.01, 1e-7, 0.5),
+		&problem,
+		0,
+		40,
+		mned.HermiteForIVP(&problem),
+	)
+	coord := solution.PointCoords()
+	if err := plot.AddPointGroup("Position (m)", "lines", [][]float64{
+		coord[0], coord[1],
+	}); err != nil {
+		fmt.Printf("Drawing the position: %v\n", err)
+	}
+	if err := plot.AddPointGroup("Velocity (m/s)", "lines", [][]float64{
+		coord[0], coord[2],
+	}); err != nil {
+		fmt.Printf("Drawing the velocity: %v\n", err)
+	}
+}
+
+func main() {
+	spring1(0)
+	spring1(1.3)
+	spring1(2.4)
+	spring1(3.5)
+}