Commit a716276a authored by Cristian Lalescu's avatar Cristian Lalescu
Browse files

add more docstrings to tools

parent 56ae48ca
......@@ -35,7 +35,7 @@ def generate_data_3D(
"""returns the Fourier representation of a Gaussian random field.
The generated field is scalar (single component), in practice a
3D `numpy` complex-valued array.
3D ``numpy`` complex-valued array.
The field will use the FFTW representation, with the slowest
direction corresponding to :math:`y`, the intermediate to :math:`z`
and the fastest direction to :math:`x`.
......@@ -53,8 +53,8 @@ def generate_data_3D(
:type p: float
:type amplitude: float
:returns: `a`, a complex valued 3D `numpy.array` that uses the FFTW
layout.
:returns: ``a``, a complex valued 3D ``numpy.array`` that uses the
FFTW layout.
"""
assert(n0 % 2 == 0 and n1 % 2 == 0 and n2 % 2 == 0)
a = np.zeros((n1, n0, n2/2+1), dtype = dtype)
......@@ -80,7 +80,7 @@ def generate_data_3D(
def randomize_phases(v):
"""randomize the phases of an FFTW complex field.
Given some `numpy.array` of dimension at least 3, with values
Given some ``numpy.array`` of dimension at least 3, with values
corresponding to the FFTW layout for the Fourier representation,
randomize the phases (assuming that the initial field is complex
valued; otherwise I'm not sure what will come out).
......@@ -104,19 +104,36 @@ def padd_with_zeros(
a,
n0, n1, n2,
odtype = None):
""""grows" a complex FFTW field by adding modes with 0 amplitude
:param a: ``numpy.array`` of dimension at least 3
:param n0: number of :math:`z` nodes on desired real-space grid
:param n1: number of :math:`y` nodes on desired real-space grid
:param n2: number of :math:`x` nodes on desired real-space grid
:param odtype: data type to use --- in principle conversion between
single and double precision can be performed with this
function as well.
:type n0: int
:type n1: int
:type n2: int
:type odtype: numpy.dtype
:returns: ``b``, a ``numpy.array`` of size
``(n1, n0, n2//2+1) + a.shape[3:]``, with all modes
not present in ``a`` set to 0.
"""
if (type(odtype) == type(None)):
odtype = a.dtype
assert(a.shape[0] <= n0 and
a.shape[1] <= n1 and
a.shape[2] <= n2)
a.shape[2] <= n2//2+1)
b = np.zeros((n0, n1, n2/2 + 1) + a.shape[3:], dtype = odtype)
m0 = a.shape[0]
m1 = a.shape[1]
m0 = a.shape[1]
m1 = a.shape[0]
m2 = a.shape[2]
b[ :m0/2, :m1/2, :m2/2+1] = a[ :m0/2, :m1/2, :m2/2+1]
b[ :m0/2, n1-m1/2: , :m2/2+1] = a[ :m0/2, m1-m1/2: , :m2/2+1]
b[n0-m0/2: , :m1/2, :m2/2+1] = a[m0-m0/2: , :m1/2, :m2/2+1]
b[n0-m0/2: , n1-m1/2: , :m2/2+1] = a[m0-m0/2: , m1-m1/2: , :m2/2+1]
b[ :m1//2, :m0//2, :m2//2+1] = a[ :m1//2, :m0//2, :m2//2+1]
b[ :m1//2, n0-m0//2: , :m2//2+1] = a[ :m1//2, m0-m0//2: , :m2//2+1]
b[n1-m1//2: , :m0//2, :m2//2+1] = a[m1-m1//2: , :m0//2, :m2//2+1]
b[n1-m1//2: , n0-m0//2: , :m2//2+1] = a[m1-m1//2: , m0-m0//2: , :m2//2+1]
return b
def get_kindices(
......@@ -169,6 +186,17 @@ except ImportError:
def get_fornberg_coeffs(
x = None,
a = None):
"""compute finite difference coefficients
Compute finite difference coefficients for a generic grid specified
by ``x``, according to [Fornberg]_.
The function is used by :func:`particle_finite_diff_test`.
.. [Fornberg] B. Fornberg,
*Generation of Finite Difference Formulas on Arbitrarily Spaced Grids*.
Mathematics of Computation,
**51:184**, 699-706, 1988
"""
N = len(a) - 1
d = []
for m in range(N+1):
......@@ -201,6 +229,13 @@ def particle_finite_diff_test(
m = 3,
species = 0,
plot_on = False):
"""sanity test for particle data.
Compare finite differences of particle positions with sampled
velocities and accelerations.
.. seealso:: :func:`get_fornberg_coeffs`
"""
d = c.get_data_file()
group = d['particles/tracers{0}'.format(species)]
acc_on = 'acceleration' in group.keys()
......
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