def velocity_bc(self):
"""
generate code for updating stress field boundary ghost cells
- generate inner loop by inserting boundary code (saved in field.bc)
- recursive insertion to generate nested loop
- loop through all velocity fields and sides
return generated code as string
"""
tmpl = self.lookup.get_template('generic_loop.txt')
result = ''
for d in range(self.dimension):
# update the staggered field first
# because other fields depends on it
sequence = [f for f in self.vfields if f.staggered[d+1]] \
+ [f for f in self.vfields if not f.staggered[d+1]]
for field in sequence:
for side in range(2):
# skip if this boundary calculation is not needed
if field.bc[d+1][side] == '':
continue
if self.omp:
result += '#pragma omp for\n'
body = ''
for d2 in range(self.dimension-1, -1, -1):
# loop through other dimensions
if not d2 == d:
i = self.index[d2]
i0 = 1
i1 = self.dim[d2]-1
if body == '':
# inner loop, populate ghost cell calculation
body = field.bc[d+1][side]
dict1 = {'i': i, 'i0': i0,
'i1': i1, 'body': body}
body = render(tmpl, dict1).replace('[t]',
'[t1]')
if self.ivdep:
body = '%s\n' % self.compiler._ivdep + body
if self.simd:
body = '#pragma simd\n' + body
else:
dict1 = {'i': i, 'i0': i0,
'i1': i1, 'body': body}
body = render(tmpl, dict1).replace('[t]',
'[t1]')
result += body
return result
def time_stepping(self):
"""
generate time index variable for time stepping
e.g. for 2nd order time-accurate scheme, varibales are t0, t1
for 4th order time-accurate scheme, variables are t0, t1, t2, t3
the variables are used to address the field arrays
e.g. in 2nd order scheme, U[t1] will be updated using U[t0]
the variables are calculated by taking mod with time periodicity
return generated code as string
"""
result = ''
tmpl = self.lookup.get_template('time_stepping.txt')
_ti = Symbol('_ti')
body = ''
for i in range(len(self.time)):
lhs = self.time[i].name
if i == 0:
rhs = ccode(_ti % self.tp)
else:
rhs = ccode((self.time[i-1]+1) % self.tp)
body += lhs + ' = ' + rhs + ';\n'
dict1 = {'body': body}
result = render(tmpl, dict1)
return result
def converge_test(self):
"""
- generate code for convergence test
- convergence test implemented by calculating L2 norm
of the simulation against analytical solution
- L2 norm of each field is calculated and output with printf()
- return generated code as string
"""
result = ''
if not self.converge:
return result
tmpl = self.lookup.get_template('generic_loop.txt')
m = self.margin.value
ti = self.ntsteps.value % 2 # last updated grid
loop = [Symbol('_'+x.name) for x in self.index] # symbols for loop
for i in range(len(self.spacing)):
result += 'printf("' + str(self.spacing[i].value) + '\\n");\n'
for field in self.sfields+self.vfields:
body = ''
l2 = ccode(field.label)+'_l2'
idx = [ti] + loop
result += self.real_t + ' ' + l2 + ' = 0.0;\n'
# populate xvalue, yvalue zvalue code
for d in range(self.dimension-1, -1, -1):
i = loop[d]
i0 = m
if field.staggered[d+1]:
i1 = ccode(self.dim[d]-m-1)
expr = self.spacing[d]*(loop[d] - self.margin.value + 0.5)
else:
i1 = ccode(self.dim[d]-m)
expr = self.spacing[d]*(loop[d] - self.margin.value)
pre = self.real_t + ' ' + self.index[d].name + '= ' \
+ ccode(expr) + ';\n'
if d == self.dimension-1:
# inner loop
tn = self.dt.value*self.ntsteps.value \
if not field.staggered[0] \
else self.dt.value*self.ntsteps.value \
+ self.dt.value/2.0
body = l2 + '+=' \
+ ccode((field[idx] -
(field.sol.subs(self.t, tn)))**2.0) + ';\n'
body = pre + body
dict1 = {'i': i, 'i0': i0, 'i1': i1, 'body': body}
body = render(tmpl, dict1)
result += body
volume = 1.0
for i in range(len(self.spacing)):
volume *= self.spacing[i].value
l2_value = 'pow(' + l2 + '*' + ccode(volume) + ', 0.5)'
result += 'conv->%s = %s;\n' % (l2, l2_value)
return result
def vtk_save_field(self):
"""
generate code to output this field with vtk
uses Mako template
returns the generated code as string
"""
tmpl = self.lookup.get_template('save_field.txt')
result = ''
dict1 = {'filename': ccode(self.label)+'_', 'field': ccode(self.label)}
result = render(tmpl, dict1)
return result
def initialise(self):
"""
generate code for initialisation of the fields
- substitute starting time to the analytical function of the fields
- substitute field coordinates calculated from array indices
to the analytical function of the fields
- generate inner loop by inserting kernel into Mako template
- recursive insertion to generate nested loop
return generated code as string
"""
tmpl = self.lookup.get_template('generic_loop.txt')
result = ''
m = self.margin.value
loop = [Symbol('_'+x.name) for x in self.index] # symbols for loop
for field in self.sfields+self.vfields:
body = ''
if self.omp:
result += '#pragma omp for\n'
# populate xvalue, yvalue zvalue code
for d in range(self.dimension-1, -1, -1):
i = loop[d]
i0 = m
if field.staggered[d+1]:
i1 = ccode(self.dim[d]-m-1)
expr = self.spacing[d]*(loop[d] - self.margin.value + 0.5)
else:
i1 = ccode(self.dim[d]-m)
expr = self.spacing[d]*(loop[d] - self.margin.value)
pre = self.real_t + ' ' + self.index[d].name + '= ' \
+ ccode(expr) + ';\n'
post = ''
if d == self.dimension-1:
# inner loop
# first time step
t0 = self.dt.value/2 if field.staggered[0] else 0
sol = field.sol.subs(self.t, t0)
if self.read:
sol = sol.subs(field.media_param)
for idx in self.index:
sol = sol.subs(idx, '_'+idx.name)
body = ccode(field[[0]+loop]) + '=' \
+ ccode(sol) + ';\n'
body = pre + body + post
dict1 = {'i': i, 'i0': i0, 'i1': i1, 'body': body}
body = render(tmpl, dict1)
result += body
return result
def vtk_save_field(self):
"""
generate code to output this field with vtk
uses Mako template
returns the generated code as string
"""
tmpl = self.lookup.get_template('save_field.txt')
result = ''
dict1 = {
'filename': ccode(self.label) + '_',
'field': ccode(self.label)
}
result = render(tmpl, dict1)
return result
def simple_loop(self, kernel):
"""
- helper function to generate simple nested loop over the entire domain
(not including ghost cells) with kernel at the inner loop
- variables defined in self.index are used as loop variables
"""
result = ''
tmpl = self.lookup.get_template('generic_loop.txt')
m = self.margin.value
for d in range(self.dimension-1, -1, -1):
i = self.index[d]
i0 = m
i1 = ccode(self.dim[d]-m)
if d == self.dimension-1:
# inner loop
result += kernel + ';\n'
dict1 = {'i': i, 'i0': i0, 'i1': i1, 'body': result}
result = render(tmpl, dict1)
return result
def velocity_loop(self):
"""
generate code for velocity field update loop
- loop through velocity fields to generate code of computation kernel
- generate inner loop by inserting kernel into Mako template
- recursive insertion to generate nested loop
return generated code as string
"""
tmpl = self.lookup.get_template('generic_loop.txt')
m = self.margin.value
body = ''
for d in range(self.dimension-1, -1, -1):
i = self.index[d]
i0 = m
i1 = ccode(self.dim[d]-m)
if d == self.dimension-1:
# inner loop
idx = [self.time[1]] + self.index
for field in self.vfields:
body += ccode(field[idx]) + '=' \
+ ccode(field.fd_align.xreplace({self.t+1:
self.time[1],
self.t:
self.time[0]})) \
+ ';\n'
dict1 = {'i': i, 'i0': i0, 'i1': i1, 'body': body}
body = render(tmpl, dict1)
if self.ivdep and d == self.dimension-1:
body = '%s\n' % self.compiler._ivdep + body
if self.simd and d == self.dimension-1:
body = '#pragma simd\n' + body
if self.omp:
body = '#pragma omp for\n' + body
return body
