def nufft1d2(x,
c,
isign,
eps,
f,
debug=0,
spread_debug=0,
spread_sort=2,
fftw=0,
modeord=0,
chkbnds=1,
upsampfac=2.0):
"""1D type-2 (aka forward) complex nonuniform fast Fourier transform
::
c[j] = SUM f[k1] exp(+/-i k1 x[j]) for j = 0,...,nj-1
k1
where sum is over -ms/2 <= k1 <= (ms-1)/2.
Args:
x (float[nj]): nonuniform target points, valid only in [-3pi,3pi]
c (complex[nj]): output values at targets. Should be initialized as a
numpy array of the correct size
isign (int): if >=0, uses + sign in exponential, otherwise - sign
eps (float): precision requested (>1e-16)
f (complex[ms]): Fourier mode coefficients, where ms is even or odd
In either case the mode indices are integers in [-ms/2, (ms-1)/2]
debug (int, optional): 0 (silent), 1 (print timing breakdown)
spread_debug (int, optional): 0 (silent), 1, 2... (print spreader info)
spread_sort (int, optional): 0 (don't sort NU pts in spreader), 1 (sort),
2 (heuristic decision to sort)
fftw (int, optional): 0 (use FFTW_ESTIMATE), 1 (use FFTW_MEASURE)
modeord (int, optional): 0 (CMCL increasing mode ordering), 1 (FFT ordering)
chkbnds (int, optional): 0 (don't check NU points valid), 1 (do)
upsampfac (float): either 2.0 (default), or 1.25 (low RAM & small FFT size)
.. note::
The output is written into the c array.
Returns:
int: 0 if success, 1 if eps too small,
2 if size of arrays to malloc exceed MAX_NF,
4 at least one NU point out of range (if chkbnds true)
Example:
see ``python_tests/accuracy_speed_tests.py``
"""
# c is the output and must have dtype=np.complex128
x = x.astype(np.float64, copy=False) #copies only if type changes
f = f.astype(np.complex128, copy=False) #copies only if type changes
return finufftpy_cpp.finufft1d2_cpp(x, c, isign, eps, f, debug,
spread_debug, spread_sort, fftw,
modeord, chkbnds, upsampfac)
def finufft1d2(x,
c,
isign,
eps,
f,
debug=0,
spread_debug=0,
spread_sort=1,
fftw=0,
modeord=0,
chkbnds=1):
"""1D type-2 (aka forward) complex nonuniform fast Fourier transform
c[j] = SUM f[k1] exp(+/-i k1 x[j]) for j = 1,...,nj
k1
where sum is over -ms/2 <= k1 <= (ms-1)/2.
Inputs:
x (float[nj]): nonuniform target points, valid only in [-3pi,3pi]
f (complex[ms]): Fourier mode coefficients, where ms is even or odd.
In either case the mode indices are integers in [-ms/2, (ms-1)/2]
isign (int): if >=0, uses + sign in exponential, otherwise - sign.
eps (float): precision requested (>1e-16)
Optional inputs:
debug (int): 0 (silent), 1 (print timing breakdown).
spread_debug (int): 0 (spreader silent), 1, 2... (print spreader info)
spread_sort (int): 0 (don't sort NU pts in spreader), 1 (sort)
fftw (int): 0 (use FFTW_ESTIMATE), 1 (use FFTW_MEASURE), ...
modeord (int): 0 (CMCL increasing mode ordering), 1 (FFT ordering)
chkbnds (int): 0 (don't check NU points valid), 1 (do).
Outputs:
c (complex[nj]): values at targets
Returns:
error status, 0 : success
1 : eps too small
2 : size of arrays to malloc exceed MAX_NF
4 : if chkbnds, at least one NU point out of range
Example:
see python_tests/accuracy_speed_tests.py
"""
# c is the output and must have dtype=np.complex128
x = x.astype(np.float64, copy=False) #copies only if type changes
f = f.astype(np.complex128, copy=False) #copies only if type changes
return finufftpy_cpp.finufft1d2_cpp(x, c, isign, eps, f, debug,
spread_debug, spread_sort, fftw,
modeord, chkbnds)