invars: simplify

Use cumulative_trapezoid() which does exactly what we want.

1 files changed, 2 insertions, 8 deletions

diff --git a/invars.py b/invars.py
index db9b674..70eb1c8 100644
--- a/invars.py
+++ b/invars.py
@@ -1,8 +1,7 @@
 import numpy             as np
-import scipy.interpolate as interp
 import scipy.integrate   as integrate
 
-def calc_dist_proper(coord, gXX):
+def dist_proper(coord, gXX):
     """
     Calculate proper distance along given spatial axis.
 
@@ -11,9 +10,4 @@ def calc_dist_proper(coord, gXX):
                            provided coordinates.
     :return: array of proper distances from coord[0].
     """
-    r_proper = np.empty_like(coord)
-    sqgXX    = interp.interp1d(coord, np.sqrt(gXX))
-    r_proper[0] = 0.0
-    for i in range(coord.shape[0] - 1):
-        r_proper[i + 1] = r_proper[i] + integrate.quad(sqgXX, coord[i], coord[i + 1])[0]
-    return r_proper
+    return integrate.cumulative_trapezoid(np.sqrt(gXX), coord, initial = 0.0)