108 lines
3.4 KiB
Python
Executable File
108 lines
3.4 KiB
Python
Executable File
import numpy as np
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def rot2D(ang):
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"""
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Return the 2D rotation matrix of given angle in degrees
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"""
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alpha = np.pi * ang / 180
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return np.array([[np.cos(alpha), np.sin(alpha)], [-np.sin(alpha), np.cos(alpha)]])
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def princ_angle(ang):
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"""
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Return the principal angle in the 0° to 180° quadrant as PA is always
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defined at p/m 180°.
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"""
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if not isinstance(ang, np.ndarray):
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A = np.array([ang])
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else:
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A = np.array(ang)
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while np.any(A < 0.0):
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A[A < 0.0] = A[A < 0.0] + 360.0
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while np.any(A >= 180.0):
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A[A >= 180.0] = A[A >= 180.0] - 180.0
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if type(ang) is type(A):
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return A
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else:
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return A[0]
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def PCconf(QN, UN, QN_ERR, UN_ERR):
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"""
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Compute the confidence level for 2 parameters polarisation degree and
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polarisation angle from the PCUBE analysis.
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"""
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mask = np.logical_and(QN_ERR > 0.0, UN_ERR > 0.0)
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conf = np.full(QN.shape, -1.0)
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chi2 = QN**2 / QN_ERR**2 + UN**2 / UN_ERR**2
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conf[mask] = 1.0 - np.exp(-0.5 * chi2[mask])
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return conf
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def CenterConf(mask, PA, sPA):
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"""
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Compute the confidence map for the position of the center of emission.
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"""
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chi2 = np.full(PA.shape, np.nan)
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conf = np.full(PA.shape, -1.0)
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yy, xx = np.indices(PA.shape)
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def ideal(c):
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itheta = np.full(PA.shape, np.nan)
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itheta[(xx + 0.5) != c[0]] = np.degrees(np.arctan((yy[(xx + 0.5) != c[0]] + 0.5 - c[1]) / (xx[(xx + 0.5) != c[0]] + 0.5 - c[0])))
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itheta[(xx + 0.5) == c[0]] = PA[(xx + 0.5) == c[0]]
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return princ_angle(itheta)
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def chisq(c):
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return np.sum((princ_angle(PA[mask]) - ideal((c[0], c[1]))[mask]) ** 2 / sPA[mask] ** 2) / np.sum(mask)
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for x, y in zip(xx[np.isfinite(PA)], yy[np.isfinite(PA)]):
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chi2[y, x] = chisq((x, y))
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from scipy.optimize import minimize
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from scipy.special import gammainc
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conf[np.isfinite(PA)] = 1.0 - gammainc(0.5, 0.5 * chi2[np.isfinite(PA)])
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result = minimize(chisq, np.array(PA.shape) / 2.0, bounds=[(0, PA.shape[1]), (0.0, PA.shape[0])])
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if result.success:
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print("Center of emission found")
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else:
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print("Center of emission not found")
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return conf, result.x
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def sci_not(v, err, rnd=1, out=str):
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"""
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Return the scientifque error notation as a string.
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"""
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power = -int(("%E" % v)[-3:]) + 1
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output = [r"({0}".format(round(v * 10**power, rnd)), round(v * 10**power, rnd)]
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if isinstance(err, list):
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for error in err:
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output[0] += r" $\pm$ {0}".format(round(error * 10**power, rnd))
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output.append(round(error * 10**power, rnd))
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else:
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output[0] += r" $\pm$ {0}".format(round(err * 10**power, rnd))
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output.append(round(err * 10**power, rnd))
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if out is str:
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return output[0] + r")e{0}".format(-power)
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else:
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return *output[1:], -power
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def wcs_PA(PC21, PC22):
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"""
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Return the position angle in degrees to the North direction of a wcs
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from the values of coefficient of its transformation matrix.
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"""
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if (abs(PC21) > abs(PC22)) and (PC21 >= 0):
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orient = -np.arccos(PC22) * 180.0 / np.pi
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elif (abs(PC21) > abs(PC22)) and (PC21 < 0):
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orient = np.arccos(PC22) * 180.0 / np.pi
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elif (abs(PC21) < abs(PC22)) and (PC22 >= 0):
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orient = np.arccos(PC22) * 180.0 / np.pi
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elif (abs(PC21) < abs(PC22)) and (PC22 < 0):
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orient = -np.arccos(PC22) * 180.0 / np.pi
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return orient
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