def nufft1d3(x,
c,
isign,
eps,
s,
f,
debug=0,
spread_debug=0,
spread_sort=2,
fftw=0,
upsampfac=2.0):
"""1D type-3 (NU-to-NU) complex nonuniform fast Fourier transform
::
nj-1
f[k] = SUM c[j] exp(+-i s[k] x[j]), for k = 0, ..., nk-1
j=0
Args:
x (float[nj]): nonuniform source points, in R
c (complex[nj]): source strengths
isign (int): if >=0, uses + sign in exponential, otherwise - sign
eps (float): precision requested (>1e-16)
s (float[nk]): nonuniform target frequency points, in R
f (complex[nk]): output values at target frequencies.
Should be initialized as a numpy array of the correct size
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)
upsampfac (float): either 2.0 (default), or 1.25 (low RAM & small FFT size)
.. note::
The output is written into the f array.
Returns:
int: 0 if success, 1 if eps too small,
2 if size of arrays to malloc exceed MAX_NF
Example:
see ``python_tests/accuracy_speed_tests.py``
"""
# f is the output and must have dtype=np.complex128
x = x.astype(np.float64, copy=False) #copies only if type changes
c = c.astype(np.complex128, copy=False) #copies only if type changes
s = s.astype(np.float64, copy=False) #copies only if type changes
return finufftpy_cpp.finufft1d3_cpp(x, c, isign, eps, s, f, debug,
spread_debug, spread_sort, fftw,
upsampfac)
def finufft1d3(x,
c,
isign,
eps,
s,
f,
debug=0,
spread_debug=0,
spread_sort=1,
fftw=0):
"""1D type-3 (NU-to-NU) complex nonuniform fast Fourier transform
nj
f[k] = SUM c[j] exp(+-i s[k] x[j]), for k = 1, ..., nk
j=1
Inputs:
x (float[nj]): nonuniform source points, in R
c (complex[nj]): source strengths
s (float[nk]): nonuniform target frequency points, in R
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), ...
Outputs:
f (complex[nk]): values at target frequencies
Returns:
error status, 0 : success
1 : eps too small
2 : size of arrays to malloc exceed MAX_NF
Example:
see python_tests/accuracy_speed_tests.py
"""
# f is the output and must have dtype=np.complex128
x = x.astype(np.float64, copy=False) #copies only if type changes
c = c.astype(np.complex128, copy=False) #copies only if type changes
s = s.astype(np.float64, copy=False) #copies only if type changes
return finufftpy_cpp.finufft1d3_cpp(x, c, isign, eps, s, f, debug,
spread_debug, spread_sort, fftw)