def calc_vavg(tau,A,m,n,N0,Nz,c,phi,sigma=False):
"""Calculating average sediment velocities.
tau: basal shear stress
A: flow law factor
m: exponent of effective pressure
n: exponent of basal shear stress
N0: effective pressure
Nz: effective pressure gradient
c: cohesion
phi: angle of internal friction"""
za = calc_za(tau,N0,Nz,c,phi)
v = numpy.zeros(len(tau),numpy.float)
if sigma:
f = flow2
else:
f = flow1
for i in range(0,len(v)):
sys = integrate.gsl_function(f,[tau[i],A,m,n,N0,Nz,c,phi,0.])
flag,result,error,num = integrate.qng(sys,za[i],0.,1e-6, 1e-6)
if flag != 0:
print flag
if za[i]!=0:
v[i] = -result/za[i]
return v
def test_qng(self):
def f1(x,y):
return Numeric.sin(x)
sys = integrate.gsl_function(f1, None)
flag, result, error, method = integrate.qng(sys, 0, Numeric.pi, 1e-8, 1e-8)
assert(Numeric.absolute(result - 2) < 1e-7)
assert(error<1e-8)
def calc_vsld(tau,A,m,n,N0,Nz,c,phi,sigma=False):
za = calc_za(tau,N0,Nz,c,phi)
v = numpy.zeros(len(tau),numpy.float)
if sigma:
f = flow2
else:
f = flow1
for i in range(0,len(v)):
sys = integrate.gsl_function(f,[tau[i],A,m,n,N0,Nz,c,phi,None])
flag,result,error,num = integrate.qng(sys,za[i],0.,1e-8, 1e-8)
if flag != 0:
print flag
v[i] = result
return v
def run_fail():
"""Demonstrates pygsl capabilites in finding problems with callbacks
"""
def f1(x, *args):
return None
import pygsl
sys = integrate.gsl_function(f1, None)
# Enables printing debug messages. The higher the level the more information
# will be displayed
#pygsl.set_debug_level(3)
# Quite a few functions add traceback frames when they propage the error
# through the different levels. If you can not understand the error messages
# directly, looking at the source where the error occured can help.
#pygsl.add_c_traceback_frames(True)
flag, result, error, method = integrate.qng(sys, 0, numx.pi, 1e-8, 1e-8)
pygsl.set_debug_level(0)
