utils.py

# -*- coding: utf-8 -*-
"""
Created on Wed Jun 21 11:02:38 2017

@author: jazicoan
"""
import numpy as np
from math import cos, sin, atan2, hypot
import json




    # ===== Angle-related functions ===== #

def degTorad(angle):
    return((angle*np.pi/180))

    
def radTodeg(angle):
    return(angle*180/np.pi)

def wrapTo2Pi(theta):
    theta = 2.0*np.arctan(np.tan(theta/2.0))
    return(float(theta))

def wrapAngle(theta):
    if theta < 0:
        theta = theta+360
    if theta > 360:
        theta = theta%360
    return(theta) 


# ===== Switch between Coordinate System ===== #


def apparentWindCoordinatesToMWCoordinates(FxW,FyW,alpha):
    Fy = FyW*np.cos(alpha)-FxW*np.sin(alpha)
    Fx = FyW*np.sin(alpha)+FxW*np.cos(alpha)
    return (Fx,Fy)

def MWCoordinatesToBoatCoordinates(FxMW,FyMW,MWAngle):
    Fx = FxMW*np.cos(MWAngle)+FyMW*np.sin(MWAngle)
    Fy = FyMW*np.cos(MWAngle)-FxMW*np.sin(MWAngle)
    return (Fx,Fy)

def apparentWindCoordinatesToBoatCoordinates(FxW,FyW,alpha,MWAngle):
    FxMW,FyMW = apparentWindCoordinatesToMWCoordinates(FxW,FyW,alpha)
    return(MWCoordinatesToBoatCoordinates(FxMW,FyMW,MWAngle))



    # ===== Integration Schemes ===== #

def euler(x,xdot,dt):
    return(x+xdot*dt)

    # ===== loading a boat configuration ===== #

def loadConfigFile(configPath):
    with open (configPath) as data_file:
        config = json.load(data_file)
    data_file.close()
    return(config)



    # Add new functions or sections if necessary