From 0fc8dec5e0d1b0006415f40e7b3574a0c0b48ca2 Mon Sep 17 00:00:00 2001
From: "Martin K. Scherer" <m.scherer@fu-berlin.de>
Date: Fri, 10 Feb 2017 15:04:12 +0100
Subject: [PATCH] [geometry] fix compatibility with old visual studio for
 Python 2.7

Also re-enable Py27 in Appveyors build matrix.
---
 appveyor.yml                            |  8 +++++++-
 mdtraj/geometry/include/math_patch.h    | 12 +++++++++---
 mdtraj/geometry/src/_geometry.pyx       |  7 +------
 mdtraj/geometry/src/image_molecules.pxi |  4 ++++
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/appveyor.yml b/appveyor.yml
index ab2f50874..98b5f3fd4 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -10,7 +10,13 @@ environment:
     - PYTHON: "C:\\Miniconda3"
       CONDA_PY: "35"
       CONDA_NPY: "1.10"
-
+    - PYTHON: "C:\\Miniconda3"
+      CONDA_PY: "27"
+      CONDA_NPY: "1.10"
+    - PYTHON: "C:\\Miniconda3-x64"
+      CONDA_PY: "27"
+      CONDA_NPY: "1.10"
+      ARCH: "64"
     - PYTHON: "C:\\Miniconda3-x64"
       CONDA_PY: "35"
       CONDA_NPY: "1.10"
diff --git a/mdtraj/geometry/include/math_patch.h b/mdtraj/geometry/include/math_patch.h
index 742770f53..be0f74124 100644
--- a/mdtraj/geometry/include/math_patch.h
+++ b/mdtraj/geometry/include/math_patch.h
@@ -1,11 +1,14 @@
 // Math functions for old versions of visual studio
-
+#ifndef __MATH_PATH_H_
+#define __MATH_PATH_H_
 #ifdef _MSC_VER
 #if _MSC_VER < 1900 // prior to vs2015
-float roundf(float x) {
+#pragma once
+inline float roundf(float x) {
    return x >= 0.0f ? floorf(x + 0.5f) : ceilf(x - 0.5f);
 }
-double cbrt(double x) {
+
+inline double cbrt(double x) {
     if (x<0)
         return -1.0 * pow(-1.0 * x, 1.0/3.0);
     else
@@ -17,4 +20,7 @@ double cbrt(double x) {
 #define isnan(x) ((x)!=(x))
 #endif // isnan
 
+#else // use C99 compliant header.
+#include <math.h>
 #endif // _MSC_VER
+#endif // __MATH_PATH_H_
diff --git a/mdtraj/geometry/src/_geometry.pyx b/mdtraj/geometry/src/_geometry.pyx
index 0369510b8..7fff6b062 100644
--- a/mdtraj/geometry/src/_geometry.pyx
+++ b/mdtraj/geometry/src/_geometry.pyx
@@ -23,9 +23,6 @@
 ##############################################################################
 
 import sys
-import warnings
-import cython
-import numpy as np
 
 ##############################################################################
 # Headers
@@ -74,8 +71,6 @@ cdef extern from "geometry.h" nogil:
     void find_closest_contact(const float* positions, const int* group1, const int* group2,
                               int n_group1, int n_group2, const float* box_vectors_pointer,
                               int* atom1, int* atom2, float* distance)
-    float roundf(float x)
-    float floorf(float x)
 
 cdef extern from "sasa.h":
     void sasa(const int n_frames, const int n_atoms, const float* xyzlist,
@@ -239,4 +234,4 @@ def _find_closest_contact(float[:, ::1] positions,
     find_closest_contact(&positions[0,0], &group1[0], &group2[0], len(group1), len(group2), box_vectors_pointer, &atom1, &atom2, &distance)
     return (atom1, atom2, distance)
 
-include "image_molecules.pxi"
\ No newline at end of file
+include "image_molecules.pxi"
diff --git a/mdtraj/geometry/src/image_molecules.pxi b/mdtraj/geometry/src/image_molecules.pxi
index d67b4b3e9..7dea65f4c 100644
--- a/mdtraj/geometry/src/image_molecules.pxi
+++ b/mdtraj/geometry/src/image_molecules.pxi
@@ -7,6 +7,10 @@ from libcpp.vector cimport vector
 
 ctypedef np.npy_intp intp
 
+cdef extern from "math_patch.h" nogil:
+    float roundf(float x)
+    float floorf(float x)
+
 cdef void make_whole(float[:,::1] frame_positions,
                 float[:,::1] frame_unitcell_vectors,
                 intp[:,:] sorted_bonds) nogil: