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// Example visualization of parabolic throw with air friction.
//
// 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"
"github.com/JwanMan/mned"
"github.com/JwanMan/mned/ivp"
"github.com/JwanMan/mned/method"
"os"
)
func addPlot(
plot *glot.Plot, name string, arrays [][]float64, idx int, idy int,
) {
if err := plot.AddPointGroup(
name,
"lines",
[][]float64{arrays[idx], arrays[idy]}); err != nil {
fmt.Printf("Error adding %v: %w\n", name, err)
os.Exit(1)
}
}
func main() {
var end mned.Point
var err error
throw := ivp.ParabolicThrow{
Height: 300,
V0: [2]float64{100, 0},
Mass: 1,
Resistance: 0.01,
Gravity: ivp.EARTH_GRAVITY,
}
problem := throw.ToIVP()
solution := mned.CacheSolve(
method.Euler(0.01),
&problem,
mned.LinearInterpolator{},
mned.Event{
Cross: func(p *mned.Point) float64 {
return p.Value[1]
},
Tolerance: 0.01,
Action: func(p *mned.Point) bool {
end = *p
return false
},
})
solution.StepToEnd()
fmt.Printf(
"Reached ground after %v s at %v m, with (%v, %v) m/s.\n",
end.Time,
end.Value[0],
end.Value[2],
end.Value[3],
)
arrays := solution.PointCoords()
byTime, err := glot.NewPlot(2, true, false)
if err != nil {
fmt.Printf("Creating plot window: %w\n")
os.Exit(1)
}
defer byTime.Close()
if err := byTime.SetXLabel("Time (s)"); err != nil {
fmt.Printf("Adding X label: %w\n")
os.Exit(1)
}
addPlot(byTime, "X position (m)", arrays, 0, 1)
addPlot(byTime, "Y position (m)", arrays, 0, 2)
addPlot(byTime, "X speed (m/s)", arrays, 0, 3)
addPlot(byTime, "Y speed (m/s)", arrays, 0, 4)
byTraj, err := glot.NewPlot(2, true, false)
if err != nil {
fmt.Printf("Creating plot window: %w\n")
os.Exit(1)
}
defer byTraj.Close()
if err := byTraj.SetXLabel("X coordinate"); err != nil {
fmt.Printf("Adding X label: %w\n")
os.Exit(1)
}
if err := byTraj.SetYLabel("Y coordinate"); err != nil {
fmt.Printf("Adding Y label: %w\n")
os.Exit(1)
}
addPlot(byTraj, "Trajectory (m)", arrays, 1, 2)
addPlot(byTraj, "Speed trajectory (m/s)", arrays, 3, 4)
}
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