def find_theta(self, cart, rng, tol, zero):
'''
PURPOSE:
Find the optimal theta to range in the rifle.
INPUTS:
Theta - angle (begins with 0.0 rad)
dist - target range in meters
zero - distance from zero (default 0.0)
OUTCOME:
Ballistics.theta is changed to optimal theta (err < 0.01 inches)
'''
cart.y = [] # initialize the history for (new) shot
vx, vy = func.vel_comp(cart.mv, cart.theta)
cart.y0 = [0.0, vx, cart.traj[0], vy]
self.model_integrate(cart)
x = cart.y[:,0] # x-position
y = cart.y[:,2] # y-position
f = interp1d(x, y)
xint = array([rng])
yint = f(xint)
print 'yErr:', yint[0], '\ttheta:', cart.theta, '\tzero:', zero
yErr = yint[0]
if (yErr < zero and yErr > zero - tol) or \
(yErr > zero and yErr < zero + tol):
None
elif yErr > zero + tol:
cart.theta = cart.theta - math.atan( (abs(yErr) + zero) / rng ) / 1.15
self.find_theta(cart, rng, tol, zero)
elif yErr < zero - tol:
cart.theta = cart.theta + math.atan( (abs(yErr) + zero) / rng ) / 1.15
self.find_theta(cart, rng, tol, zero)
def fire_round(self, cart, theta, tol=1e-5, zero=0.0):
'''
PURPOSE:
Method to fire the rifle specified theta.
INPUT:
theta - the angle from the horizon to fire the rifle.
zero - distance from zero (default 0.0)
OUTCOME:
trajectory saved to Ballistics.x as a numpy array [x, vx, y, vy]
'''
cart.y = [] # initialize the history for (new) shot
vx, vy = func.vel_comp(cart.mv, theta)
cart.y0 = [0.0, vx, cart.traj[0], vy]
self.model_integrate(cart)