From 2ed410d7ad733b8c5eb1d1b81075b96a7e857bed Mon Sep 17 00:00:00 2001
From: Malcolm White <malcolcw@usc.edu>
Date: Fri, 14 Aug 2020 11:30:46 -0400
Subject: [PATCH] Debug Issue #8

https://github.com/malcolmw/pykonal/issues/8
---
 pykonal/__version__.py     | 2 +-
 pykonal/fields.pyx         | 9 ++++++++-
 pykonal/solver.pyx         | 5 ++++-
 pykonal/transformations.py | 8 ++++++--
 4 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/pykonal/__version__.py b/pykonal/__version__.py
index 6b077c4..4d2eafe 100644
--- a/pykonal/__version__.py
+++ b/pykonal/__version__.py
@@ -1,7 +1,7 @@
 __major_version__  = 0
 __minor_version__  = 3
 __patch__          = 2
-__release__        = "b1"
+__release__        = "b2"
 __version_tuple__ = (
     __major_version__,
     __minor_version__,
diff --git a/pykonal/fields.pyx b/pykonal/fields.pyx
index bbcfaee..a4afbb4 100644
--- a/pykonal/fields.pyx
+++ b/pykonal/fields.pyx
@@ -296,7 +296,14 @@ cdef class Field3D(object):
         :rtype: numpy.ndarray(shape=(N0,N1,N2,3), dtype=numpy.float)
         """
         if self.coord_sys == "spherical" and coord_sys.lower() == "spherical":
-            return (transformations.sph2sph(self.nodes, origin))
+            force_phi_positive = self.min_coords[2] >= 0
+            return (
+                transformations.sph2sph(
+                    self.nodes,
+                    origin,
+                    force_phi_positive=force_phi_positive
+                )
+            )
         elif self.coord_sys == "cartesian" and coord_sys.lower() == "spherical":
             return (transformations.xyz2sph(self.nodes, origin))
         elif self.coord_sys == "spherical" and coord_sys.lower() == "cartesian":
diff --git a/pykonal/solver.pyx b/pykonal/solver.pyx
index fba1b9c..14cd785 100644
--- a/pykonal/solver.pyx
+++ b/pykonal/solver.pyx
@@ -634,7 +634,10 @@ class PointSourceSolver(EikonalSolver):
         origin = (r0, t0, p0)
         # Transform the coordinates of the near-field grid nodes to the
         # far-field coordinate system.
-        nodes = self.near_field.vv.transform_coordinates(self.coord_sys, origin)
+        nodes = self.near_field.vv.transform_coordinates(
+            self.coord_sys,
+            origin
+        )
         # Find the indices of the near-field grid nodes that are inside
         # the far-field grid.
         bool_idx = True
diff --git a/pykonal/transformations.py b/pykonal/transformations.py
index 3e6a2c0..a87d596 100644
--- a/pykonal/transformations.py
+++ b/pykonal/transformations.py
@@ -26,7 +26,7 @@ def geo2sph(nodes):
     return (sph)
 
 
-def sph2sph(nodes, origin=(0,0,0)):
+def sph2sph(nodes, origin=(0,0,0), force_phi_positive=False):
     """
     Transform spherical coordinates to new spherical coordinate system.
 
@@ -55,11 +55,13 @@ def sph2sph(nodes, origin=(0,0,0)):
     tt  = np.arccos(xyz[...,2] / rr)
     np.seterr(**old)
     pp  = np.arctan2(xyz[...,1], xyz[...,0])
+    if force_phi_positive:
+        pp = np.mod(pp, 2*np.pi)
     rtp = np.moveaxis(np.stack([rr, tt, pp]), 0, -1)
     return (rtp)
 
 
-def xyz2sph(nodes, origin=(0,0,0)):
+def xyz2sph(nodes, origin=(0,0,0), force_phi_positive=False):
     """
     Transform Cartesian coordinates to new spherical coordinate system.
 
@@ -78,6 +80,8 @@ def xyz2sph(nodes, origin=(0,0,0)):
     tt  = np.arccos(xyz[...,2] / rr)
     np.seterr(**old)
     pp  = np.arctan2(xyz[...,1], xyz[...,0])
+    if force_phi_positive:
+        pp = np.mod(pp, 2*np.pi)
     rtp = np.moveaxis(np.stack([rr, tt, pp]), 0, -1)
     return (rtp)