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wavesynth: get coefficients.py into useable state
SplineSource() supports spline interpolating multi-channel tabular data, cropping it and generating wavesynth compatible segment data from it. ComposingSplineSource() needs some verification still.
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38
artiq/test/coefficients.py
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38
artiq/test/coefficients.py
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import unittest
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import numpy as np
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from artiq.wavesynth import coefficients, compute_samples
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class TestSplineCoef(unittest.TestCase):
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def setUp(self):
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self.x = np.arange(5.)
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self.y = np.sin(2*np.pi*self.x/5) + np.arange(2)[:, None]
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self.s = coefficients.SplineSource(self.x, self.y, order=4)
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def test_get_segment(self):
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return list(self.s.get_segment_data(1.5, 3.2, 1/100.))
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def test_synth(self):
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d = self.test_get_segment()
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d[0]["trigger"] = True
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return compute_samples.Synthesizer(self.y.shape[0], [d, d + d])
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def drive(self, s):
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y = []
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for f in 0, 1, None, 0:
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if f is not None:
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s.select(f)
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y += s.trigger()[0]
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return y
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def test_run(self):
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return self.drive(self.test_synth())
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@unittest.skip("manual/visual test")
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def test_plot(self):
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import cairoplot
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y = self.test_run()
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x = list(range(len(y)))
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cairoplot.scatter_plot("plot.png", [x, y])
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@ -1,67 +1,263 @@
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import numpy as np
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from scipy.interpolate import splrep, splev, spalde
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from scipy.special import binom
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class UnivariateMultiSpline:
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"""Multidimensional wrapper around `scipy.interpolate.sp*` functions.
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`scipy.inteprolate.splprep` unfortunately does only up to 12 dimsions.
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"""
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def __init__(self, x, y, order=4):
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self.order = order
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self.s = [splrep(x, yi, k=order - 1) for yi in y]
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def lev(self, x, *a, **k):
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return np.array([splev(x, si) for si in self.s])
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def alde(self, x):
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u = np.array([spalde(x, si) for si in self.s])
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if len(x) == 1:
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u = u[:, None, :]
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return u
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def __call__(self, x, use_alde=True):
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if use_alde:
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u = self.alde(x)[:, :, :self.order]
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s = (len(self.s), len(x), self.order)
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assert u.shape == s, (u.shape, s)
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return u.transpose(2, 0, 1)
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else:
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return np.array([self.lev(x, der=i) for i in range(self.order)])
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class UnivariateMultiSparseSpline(UnivariateMultiSpline):
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def __init__(self, d, x0=None, order=4):
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self.order = order
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self.n = sorted(set(n for x, n, y in d))
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self.s = []
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for n in self.n:
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x, y = np.array([(x, y) for x, ni, y in d if n == ni]).T
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if x0 is not None:
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y0 = splev(x0, splrep(x, y, k=order - 1))
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x, y = x0, y0
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s = splrep(x, y, k=order - 1)
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self.s.append(s)
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def pad_const(x, n, axis=0):
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"""Prefix and postfix the array `x` by `n` repetitions of the first and
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last vlaue along `axis`.
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"""
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a = np.repeat(x.take([0], axis), n, axis)
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b = np.repeat(x.take([-1], axis), n, axis)
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xp = np.concatenate([a, x, b], axis)
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s = list(x.shape)
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s[axis] += 2*n
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assert xp.shape == tuple(s), (x.shape, s, xp.shape)
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return xp
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def build_segment(durations, coefficients, target="bias",
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variable="amplitude"):
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"""Build a wavesynth-style segment from homogeneous duration and
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coefficient data.
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:param durations: 1D sequence of line durations.
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:param coefficients: 3D array with shape `(n, m, len(x))`,
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with `n` being the interpolation order + 1 and `m` the number of
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channels.
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:param target: The target component of the channel to affect.
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:param variable: The variable within the target component.
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"""
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for dxi, yi in zip(durations, coefficients.transpose()):
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d = {"duration": int(dxi)}
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d["channel_data"] = cd = []
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for yij in yi:
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cdj = []
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for yijk in reversed(yij):
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if cdj or abs(yijk):
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cdj.append(float(yijk))
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cdj.reverse()
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cd.append({target: {variable: cdj}})
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yield d
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class CoefficientSource:
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def get_times(self, t, speed, clock):
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pass
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def crop_x(self, start, stop, num=2):
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"""Return an array of valid sample positions.
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def get_coefficients(self, t, speed):
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pass
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This function needs to be implemented only if this
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`CoefficientSource` does not support sampling at arbitrary
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positions.
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def get_program(self, dt, u):
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pass
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:param start: First sample position.
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:param stop: Last sample position.
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:param num: Number of samples between `start` and `stop`.
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:return: Array of sample positions. `start` and `stop` should be
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returned as the first and last value in the array respectively.
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"""
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return np.linspace(start, stop, num)
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def scale_x(self, x, scale):
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"""Scale and round sample positions.
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:param x: Input sample positions in data space.
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:param scale: Data space position to cycles conversion scale,
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in units of x-units per clock cycle.
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:return: `x_sample`, the rounded sample positions and `durations`, the
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integer durations of the individual samples in cycles.
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"""
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raise NotImplementedError
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def __call__(self, x, **kwargs):
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"""Perform sampling and return coefficients.
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:param x: Sample positions.
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:return: `y` the array of coefficients. `y.shape == (order, n, len(x))`
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with `n` being the number of channels."""
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raise NotImplementedError
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def get_segment_data(self, start, stop, scale, cutoff=1e-12,
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min_duration=1, min_length=20,
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target="bias", variable="amplitude"):
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"""Build wavesynth segment data.
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:param start: see `crop_x()`.
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:param stop: see `crop_x()`.
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:param scale: see `scale_x()`.
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:param num: see `crop_x()`.
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:param cutoff: coefficient cutoff towards zero to compress data.
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:param min_duration: Minimum duration of a line.
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:param min_length: Minimum segment length to space triggers.
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"""
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x = self.crop_x(start, stop)
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x_sample, durations = self.scale_x(x, scale)
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coefficients = self(x_sample)
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np.clip(np.fabs(durations), min_duration, None, out=durations)
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if len(durations) == 1:
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durations[0] = max(durations[0], min_length)
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if start == stop:
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coefficients = coefficients[:1]
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# rescale coefficients accordingly
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coefficients *= (scale*np.sign(durations))**np.arange(
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coefficients.shape[0])[:, None, None]
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if cutoff:
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coefficients[np.fabs(coefficients) < cutoff] = 0
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return build_segment(durations, coefficients, target=target,
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variable=variable)
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def extend_segment(self, segment, *args, **kwargs):
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"""Extend a wavesynth segment.
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See `get_segment()` for arguments.
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"""
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for line in self.get_segment_data(*args, **kwargs):
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segment.add_line(**line)
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def _round_times(times, sample_times=None):
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times = np.asanyarray(times)
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if sample_times is None:
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sample_times = np.rint(times)
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duration = np.diff(sample_times)
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sample_times = sample_times[:-1]
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assert np.all(duration >= 0)
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assert np.all(duration < (1 << 16))
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return times, sample_times, duration
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class SplineSource(CoefficientSource):
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def __init__(self, x, y, order=4, pad_dx=1.):
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"""
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:param x: 1D sample positions.
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:param y: 2D sample values.
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"""
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self.x = np.asanyarray(x)
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assert self.x.ndim == 1
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self.y = np.asanyarray(y)
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assert self.y.ndim == 2
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if pad_dx is not None:
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a = np.arange(-order, 0)*pad_dx + self.x[0]
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b = self.x[-1] + np.arange(1, order + 1)*pad_dx
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self.x = np.r_[a, self.x, b]
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self.y = pad_const(self.y, order, axis=1)
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assert self.y.shape[1] == self.x.shape[0]
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self.spline = UnivariateMultiSpline(self.x, self.y, order)
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def crop_x(self, start, stop):
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ia, ib = np.searchsorted(self.x, (start, stop))
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if start > stop:
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x = self.x[ia - 1:ib - 1:-1]
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else:
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x = self.x[ia:ib]
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return np.r_[start, x, stop]
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def scale_x(self, x, scale, nudge=1e-9):
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# We want to only sample a spline at t_knot + epsilon
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# where the highest order derivative has just jumped
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# and is valid at least up to the next knot after t_knot.
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#
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# To ensure that we are on the right side of a knot:
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# * only ever increase t when rounding (for increasing t)
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# * or only ever decrease it (for decreasing t)
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#
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# The highest derivative is discontinuous at t
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# and the correct value for a segment is obtained
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# for t_int >= t_float == t_knot (and v.v. for t decreasing).
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x = x/scale
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inc = np.diff(x) >= 0
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inc = np.r_[inc, inc[-1]]
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x = np.where(inc, np.ceil(x + nudge), np.floor(x - nudge))
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if len(x) > 1 and x[0] == x[1]:
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x = x[1:]
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if len(x) > 1 and x[-2] == x[-1]:
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x = x[:-1]
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x_sample = x[:-1]*scale
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durations = np.diff(x.astype(np.int))
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return x_sample, durations
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def __call__(self, x):
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return self.spline(x)
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def _interpolate(time, data, sample_times, order=3):
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# FIXME: this does not ensure that the spline does not clip
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spline = splrep(time, data, k=order or 1)
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# FIXME: this could be faster but needs k knots outside t_eval
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# dv = np.array(spalde(t_eval, s))
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coeffs = np.array([splev(sample_times, spline, der=i, ext=0)
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for i in range(order + 1)]).T
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return coeffs
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class ComposingSplineSource(SplineSource):
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# TODO
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def __init__(self, x, y, components, order=4, pad_dx=1.):
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self.x = np.asanyarray(x)
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assert self.x.ndim == 1
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self.y = np.asanyarray(y)
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assert self.y.ndim == 3
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if pad_dx is not None:
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a = np.arange(-order, 0)*pad_dx + self.x[0]
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b = self.x[-1] + np.arange(1, order + 1)*pad_dx
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self.x = np.r_[a, self.x, b]
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self.y = pad_const(self.y, order, axis=2)
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assert self.y.shape[2] == self.x.shape[0]
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self.splines = [UnivariateMultiSpline(self.x, yi, order)
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for yi in self.y]
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def _zip_program(times, channels, target):
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for tc in zip(times, *channels):
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yield {
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"duration": tc[0],
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"channel_data": tc[1:],
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}
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# FIXME: this does not handle:
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# `clear` (clearing the phase accumulator)
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# `silence` (stopping the dac clock)
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# need to resample/upsample the shim splines to the master spline knots
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# shim knot spacings can span an master spline knot and thus would
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# cross a highest order derivative boundary
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self.components = UnivariateMultiSparseSpline(
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components, self.x, order)
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def __call__(self, t, gain={}, offset={}):
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der = list((set(self.components.n) | set(offset)) & set(self.der))
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u = np.zeros((self.splines[0].order, len(self.splines[0].s), len(t)))
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# der, order, ele, t
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p = np.array([self.splines[i](t) for i in der])
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# order, der, None, t
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s = self.components(t)
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s_gain = np.array([gain.get(_, 1.) for _ in self.components.n])
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s = s[:, :, None, :]*s_gain[None, :, None, None]
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for k, v in offset.items():
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if v and k in self.der:
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u += v*p[self.der.index(k)]
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ps = p[[self.der.index(_) for _ in self.shims.der]]
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for i in range(u.shape[1]):
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for j in range(i + 1):
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u[i] += binom(i, j)*(s[j]*ps[:, i - j]).sum(0)
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return u # (order, ele, t)
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def interpolate_channels(times, data, sample_times=None, **kwargs):
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if len(times) == 1:
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return _zip_program(np.array([1]), data[:, :, None])
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data = np.asanyarray(data)
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assert len(times) == len(data)
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times, sample_times, duration = _round_times(times, sample_times)
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channel_coeff = [_interpolate(sample_times, i, **kwargs) for i in data.T]
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return _zip_program(duration, np.array(channel_coeff))
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# v = np.clip(v/self.max_out, -1, 1)
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#
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#
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def discrete_compensate(c):
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"""Compensate spline coefficients for discrete accumulators
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Given continuous time b-spline coefficients, this function
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Given continuous-time b-spline coefficients, this function
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compensates for the effect of discrete time steps in the
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target devices.
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@ -81,17 +81,17 @@ class Synthesizer:
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def select(self, selection):
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if self.line_iter is not None:
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raise TriggerError
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raise TriggerError("a frame is already selected")
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self.line_iter = iter(self.program[selection])
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self.line = next(self.line_iter)
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def trigger(self):
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if self.line_iter is None:
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raise TriggerError
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raise TriggerError("no frame selected")
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line = self.line
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if not line.get("trigger", False):
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raise TriggerError
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raise TriggerError("segment is not triggered")
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r = [[] for _ in self.channels]
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while True:
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