From 458e2cb98e95980f75f82b6639beb1f28b52d286 Mon Sep 17 00:00:00 2001
From: Chad Hanna <chad.hanna@comp-hd-001.gwave.ics.psu.edu>
Date: Thu, 6 Jun 2019 22:10:38 -0400
Subject: [PATCH] metric.py: add new coordinate system
---
gstlal-ugly/python/metric.py | 66 +++++++++++++++++++++++++++++++++++-
1 file changed, 65 insertions(+), 1 deletion(-)
diff --git a/gstlal-ugly/python/metric.py b/gstlal-ugly/python/metric.py
index 71d4c2e8d7..0a7891612f 100644
--- a/gstlal-ugly/python/metric.py
+++ b/gstlal-ugly/python/metric.py
@@ -141,6 +141,70 @@ def m1_from_mc_m2(mc, m2):
def mc_from_m1_m2(m1, m2):
return (m1 * m2)**(.6) / (m1 + m2)**.2
+# inspired by arXiv:gr-qc/9808076v1 27 Aug 1998
+
+def x_y_z_zn_func(coords):
+ s1y = s2y = s1x = s2x = 0.
+ m1 = m1_from_x_y_z_zn(*coords)
+ m2 = m2_from_x_y_z_zn(*coords)
+ s1z = s1_from_x_y_z_zn(*coords)
+ s2z = s2_from_x_y_z_zn(*coords)
+ q = m1 / m2
+ if False:#q < 1.05 and q > 0.95:
+ M = m1 + m2
+ q = 1.05
+ m2 = (M / q) / 2.
+ m1 = m2 * q
+ return [m1, m2, s1x, s1y, s1z, s2x, s2y, s2z]
+
+def x_from_m1_m2_s1_s2(m1, m2, s1, s2):
+ m1 = float(m1); m2 = float(m2); s1 = float(s1); s2 = float(s2)
+ M = m1 + m2
+ eta = m1*m2/(m1+m2)**2
+ return M**(-5/3.) / eta
+
+def y_from_m1_m2_s1_s2(m1, m2, s1, s2):
+ m1 = float(m1); m2 = float(m2); s1 = float(s1); s2 = float(s2)
+ M = m1 + m2
+ eta = m1*m2/(m1+m2)**2
+ return M**(-2/3.) / eta
+
+def z_from_m1_m2_s1_s2(m1, m2, s1, s2):
+ m1 = float(m1); m2 = float(m2); s1 = float(s1); s2 = float(s2)
+ M = m1 + m2
+ return (s1 * m1 + s2 * m2) / M
+
+def zn_from_m1_m2_s1_s2(m1, m2, s1, s2):
+ m1 = float(m1); m2 = float(m2); s1 = float(s1); s2 = float(s2)
+ M = m1 + m2
+ return (s1 * m1 - s2 * m2) / M
+
+def m1_from_x_y_z_zn(x, y, z, zn):
+ x = float(x); y = float(y)
+ M = y / x
+ eta = min((x**2 / y**5)**(1./3), 0.25)
+ m1 = (M + (M**2 * (1 - 4 * eta))**.5) / 2.
+ return m1
+
+def m2_from_x_y_z_zn(x, y, z, zn):
+ x = float(x); y = float(y)
+ M = y / x
+ eta = min((x**2 / y**5)**(1./3), 0.25)
+ m2 = M - (M + (M**2 * (1 - 4 * eta))**.5) / 2.
+ return m2
+
+def s1_from_x_y_z_zn(x, y, z, zn):
+ x = float(x); y = float(y); z = float(z); zn = float(zn)
+ M = y / x
+ m1 = m1_from_x_y_z_zn(x, y, z, zn)
+ return (z + zn) * M / m1 / 2.
+
+def s2_from_x_y_z_zn(x, y, z, zn):
+ x = float(x); y = float(y); z = float(z); zn = float(zn)
+ M = y / x
+ m2 = m1_from_x_y_z_zn(x, y, z, zn)
+ return (z - zn) * M / m2 / 2.
+
#
# Metric object that numerically evaluates the waveform metric
#
@@ -282,7 +346,7 @@ class Metric(object):
wm = {}
# FIXME assumes m1,m2,spins... as the coordinates
deltas = numpy.zeros(len(center))
- deltas[0:2] = abs(center[0:2])**.5 * DELTA
+ deltas[0:2] = abs(center[0:2]) * DELTA
deltas[2:] += DELTA
#deltas = numpy.ones(len(center), dtype=float) * DELTA
#deltas = abs(center)**.5 * DELTA + DELTA
--
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