def _Biot_Savart_SingleHelixSeg(helixseg, fieldpoint_vector, returnasVectors=False):
"""
Given a helix segment on the surface of a cylinder
and a vector indicating the field point, this function
computes Bx,By,Bz,and B2. Errors are also given. The results
are Teslas per amp of current so You can multiply the result
by the actual current to get the field.
"""
R = helixseg.cylind.radius
const = mu_0 / float(4 * pi * R)
M = helixseg.M / float(R)
phiS = helixseg.cylind_startvect.phi # this is guaranteed to be zero
if phiS != 0.0:
print "Someone has changed the definition of HelixSeg"
raise Exception
phiE = helixseg.cylind_endvect.phi
x = fieldpoint_vector.x / float(R)
y = fieldpoint_vector.y / float(R)
fieldpoint_cylind = helixseg.transform_to_helixcoords(
fieldpoint_vector
) # We need some transformation to flip into coordinates referenced to the cylinder.
z = (helixseg.cylind_startvect.z - fieldpoint_cylind.z) / float(R)
# print "x,y,z,M,phiS,phiE:",x," ",y," ",z," ",M," ",phiS," ",phiE
Bx, dBx = quadrature(Afunc, phiS, phiE, args=(x, y, z, M, phiS))
By, dBy = quadrature(Bfunc, phiS, phiE, args=(x, y, z, M, phiS))
Bz, dBz = quadrature(Cfunc, phiS, phiE, args=(x, y, z, M, phiS))
Bvect = Vector((const * Bx, const * By, const * Bz), type="CARTESIAN")
dBvect = Vector((const * dBx, const * dBy, const * dBz), type="CARTESIAN")
Bvect = helixseg.transform_from_helixcoords(Bvect)
dBvect = helixseg.transform_from_helixcoords(dBvect)
if returnasVectors == True:
return (Bvect, dBvect)
else:
return (
(Bvect.x, Bvect.y, Bvect.z, Bvect.magnitude * Bvect.magnitude),
(dBvect.x, dBvect.y, dBvect.z, (dBvect.magnitude) * (dBvect.magnitude)),
)
def KernelTest():
print Cfunc(0, 0, 0, 0, 0, 0)
print quadrature(Cfunc, 0, pi, args=(0, 0, 0, 0, 0))
