test_wgridder_experiments.py 3.23 KB
Newer Older
Martin Reinecke's avatar
Martin Reinecke committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 2020 Max-Planck-Society


import ducc0.wgridder as ng
import numpy as np
import pytest
from numpy.testing import assert_allclose

pmp = pytest.mark.parametrize


def _l2error(a, b):
    return np.sqrt(np.sum(np.abs(a-b)**2)/np.maximum(np.sum(np.abs(a)**2),
                                                     np.sum(np.abs(b)**2)))


def explicit_gridder(uvw, freq, ms, wgt, nxdirty, nydirty, xpixsize, ypixsize,
                     apply_w):
    speedoflight = 299792458.
    x, y = np.meshgrid(*[-ss/2 + np.arange(ss) for ss in [nxdirty, nydirty]],
                       indexing='ij')
    x *= xpixsize
    y *= ypixsize
    res = np.zeros((nxdirty, nydirty))
    eps = x**2+y**2
    if apply_w:
        nm1 = -eps/(np.sqrt(1.-eps)+1.)
        n = nm1+1
    else:
        nm1 = 0.
        n = 1.
    for row in range(ms.shape[0]):
        for chan in range(ms.shape[1]):
            phase = (freq[chan]/speedoflight *
                     (x*uvw[row, 0] + y*uvw[row, 1] - uvw[row, 2]*nm1))
            if wgt is None:
                res += (ms[row, chan]*np.exp(2j*np.pi*phase)).real
            else:
                res += (ms[row, chan]*wgt[row, chan]
                        * np.exp(2j*np.pi*phase)).real
    return res/n


@pmp('nxdirty', [16, 64])
@pmp('nydirty', [64])
59
60
@pmp("nrow", (1, 100))
@pmp("nchan", (1, 7))
Martin Reinecke's avatar
Martin Reinecke committed
61
62
63
64
@pmp("epsilon", list(10.**np.linspace(-2.,-12.,100)))
@pmp("singleprec", (False,))
@pmp("wstacking", (True,))
@pmp("use_wgt", (True,))
65
@pmp("nthreads", (1, 10))
Martin Reinecke's avatar
Martin Reinecke committed
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
@pmp("fov", (10.,))
def test_ms2dirty_against_wdft2(nxdirty, nydirty, nrow, nchan, epsilon, singleprec, wstacking, use_wgt, fov, nthreads):
    if singleprec and epsilon < 5e-5:
        return
    rng = np.random.default_rng()
    pixsizex = fov*np.pi/180/nxdirty
    pixsizey = fov*np.pi/180/nydirty*1.1
    speedoflight, f0 = 299792458., 1e9
    freq = f0 + np.arange(nchan)*(f0/nchan)
    uvw = (rng.random((nrow, 3))-0.5)/(pixsizex*f0/speedoflight)
    ms = rng.random((nrow, nchan))-0.5 + 1j*(rng.random((nrow, nchan))-0.5)
    wgt = rng.random((nrow, 1)) if use_wgt else None
    wgt = np.broadcast_to(wgt, (nrow, nchan)) if use_wgt else None
    if singleprec:
        ms = ms.astype("c8")
        if wgt is not None:
            wgt = wgt.astype("f4")
    try:
        dirty = ng.ms2dirty(uvw, freq, ms, wgt, nxdirty, nydirty, pixsizex,
                            pixsizey, 0, 0, epsilon, wstacking, nthreads, 0).astype("f8")
    except:
        # no matching kernel was found
        pytest.skip()
    ref = explicit_gridder(uvw, freq, ms, wgt, nxdirty, nydirty, pixsizex, pixsizey, wstacking)
    assert_allclose(_l2error(dirty, ref), 0, atol=epsilon)