def getAxisFieldFunction(fl_name):
"""
This function will read the .FSO file and extract the axis field Ez(z).
"""
fl_in = open(fl_name, "r")
lns = fl_in.readlines()
fl_in.close()
func = Function()
i_start = -1
for i in range(len(lns)):
if (lns[i].find(" Z(cm) Ez(V/m)") >= 0):
i_start = i + 1
break
for i in range(i_start, len(lns)):
res_arr = lns[i].split()
if (len(res_arr) != 2):
break
x = 0.01 * float(res_arr[0])
y = float(res_arr[1])
func.add(x, y)
#fix for the field at the 0 region
func1 = Function()
for i in range(1, func.getSize()):
ind = func.getSize() - i
x = -func.x(ind)
y = func.y(ind)
func1.add(x, y)
for i in range(func.getSize()):
x = func.x(i)
y = func.y(i)
func1.add(x, y)
return func1
#---- here we parse the input file: 1st position - z, 4th - dB/dr(z z = float(res_arr[0]) g = float(res_arr[3]) g_func.add(z,g) #---- let's set energy and momentum mass = 0.938272 + 2*0.000511 eKin = 0.0025 momentum = math.sqrt(eKin*(eKin + 2*mass)) Brho = 3.33564*momentum # [T*m] charge = -1.0 #---- now let's prepare array of 4x4 (transport) #---- and 6x6 (Twiss params transport) matrices matrix_arr = [] for ind in range(1,g_func.getSize()): z0 = g_func.x(ind-1) z1 = g_func.x(ind) g0 = g_func.y(ind-1) g1 = g_func.y(ind) z_avg = (z1+z0)/2 g_avg = (g0+g1)/2 g_avg *= charge dL = z1-z0 #print "debug dL=",dL, " y= %12.3f "%y_avg #---- this is a transport 4x4 matrix for coordinates x,x',y,y' trMtrx = Matrix(4,4) k2 = abs(g_avg/Brho) kq = math.sqrt(k2) sin_kL = math.sin(kq*dL) cos_kL = math.cos(kq*dL)