def do_integral(expr, prec, options):
func = expr.args[0]
x, (xlow, xhigh) = expr.args[1][0]
orig = mp.prec
oldmaxprec = options.get('maxprec', DEFAULT_MAXPREC)
options['maxprec'] = min(oldmaxprec, 2 * prec)
try:
mp.prec = prec + 5
xlow = as_mpmath(xlow, prec + 15, options)
xhigh = as_mpmath(xhigh, prec + 15, options)
# Integration is like summation, and we can phone home from
# the integrand function to update accuracy summation style
# Note that this accuracy is inaccurate, since it fails
# to account for the variable quadrature weights,
# but it is better than nothing
have_part = [False, False]
max_real_term = [MINUS_INF]
max_imag_term = [MINUS_INF]
def f(t):
re, im, re_acc, im_acc = evalf(func, mp.prec, {'subs': {x: t}})
have_part[0] = re or have_part[0]
have_part[1] = im or have_part[1]
max_real_term[0] = max(max_real_term[0], fastlog(re))
max_imag_term[0] = max(max_imag_term[0], fastlog(im))
if im:
return mpc(re or fzero, im)
return mpf(re or fzero)
if options.get('quad') == 'osc':
A = C.Wild('A', exclude=[x])
B = C.Wild('B', exclude=[x])
D = C.Wild('D')
m = func.match(C.cos(A * x + B) * D)
if not m:
m = func.match(C.sin(A * x + B) * D)
if not m:
raise ValueError(
"An integrand of the form sin(A*x+B)*f(x) "
"or cos(A*x+B)*f(x) is required for oscillatory quadrature"
)
period = as_mpmath(2 * S.Pi / m[A], prec + 15, options)
result = quadosc(f, [xlow, xhigh], period=period)
# XXX: quadosc does not do error detection yet
quadrature_error = MINUS_INF
else:
result, quadrature_error = quadts(f, [xlow, xhigh], error=1)
quadrature_error = fastlog(quadrature_error._mpf_)
finally:
options['maxprec'] = oldmaxprec
mp.prec = orig
if have_part[0]:
re = result.real._mpf_
if re == fzero:
re = mpf_shift(fone,
min(-prec, -max_real_term[0], -quadrature_error))
re_acc = -1
else:
re_acc = -max(max_real_term[0] - fastlog(re) - prec,
quadrature_error)
else:
re, re_acc = None, None
if have_part[1]:
im = result.imag._mpf_
if im == fzero:
im = mpf_shift(fone,
min(-prec, -max_imag_term[0], -quadrature_error))
im_acc = -1
else:
im_acc = -max(max_imag_term[0] - fastlog(im) - prec,
quadrature_error)
else:
im, im_acc = None, None
result = re, im, re_acc, im_acc
return result
