Revert "cleaned up defunct c modules"

This reverts commit 175b69c.

c_src/_polar.c

@@ -0,0 +1,70 @@
+#include <Python.h>
+#include <numpy/arrayobject.h>
+#include "polar.h"
+
+static char module_docstring[] =
+    "This module is used to calcuate the area of a triangle";
+static char polar_docstring[] =
+    "Functions for dealing with polar co-ordinates";
+
+static PyObject *polar_polar(PyObject *self, PyObject *args);
+
+static PyMethodDef module_methods[] = {
+    {"polar", polar_polar, METH_VARARGS, polar_docstring},
+    {NULL, NULL, 0, NULL}
+};
+
+PyMODINIT_FUNC
+#if PY_MAJOR_VERSION >= 3
+PyInit__polar(void)
+#else
+init_polar(void)
+#endif
+{
+	#if PY_MAJOR_VERSION >= 3
+		PyObject *module;
+		static struct PyModuleDef moduledef = {
+			PyModuleDef_HEAD_INIT,
+			"_polar",             /* m_name */
+			module_docstring,    /* m_doc */
+			-1,                  /* m_size */
+			module_methods,      /* m_methods */
+			NULL,                /* m_reload */
+			NULL,                /* m_traverse */
+			NULL,                /* m_clear */
+			NULL,                /* m_free */
+		};
+	#endif
+
+	#if PY_MAJOR_VERSION >= 3
+		module = PyModule_Create(&moduledef);
+		if (!module)
+			return NULL;
+		/* Load `numpy` functionality. */
+		import_array();
+		return module;
+	#else
+	    PyObject *m = Py_InitModule3("_polar", module_methods, module_docstring);
+		if (m == NULL)
+			return;
+		/* Load `numpy` functionality. */
+		import_array();
+	#endif
+}
+
+static PyObject *polar_polar(PyObject *self, PyObject *args)
+{
+    double r1, r2, theta1, theta2;
+
+    /* Parse the input tuple */
+    if (!PyArg_ParseTuple(args, "dddd", &r1, &r2, &theta1, &theta2))
+        return NULL;
+
+    /* Call the external C function to compute the area. */
+    double d = polar_distance(r1,r2,theta1,theta2);
+
+    /* Build the output tuple */
+
+    PyObject *ret = Py_BuildValue("d",d);
+    return ret;
+}

c_src/_test.c

@@ -0,0 +1,104 @@
+#include <Python.h>
+#include <numpy/arrayobject.h>
+#include "test.h"
+
+static char module_docstring[] =
+    "This module provides an interface for calculating chi-squared using C.";
+static char test_docstring[] =
+    "Calculate the chi-squared of some data given a model.";
+
+static PyObject *test_test(PyObject *self, PyObject *args);
+
+static PyMethodDef module_methods[] = {
+    {"test", test_test, METH_VARARGS, test_docstring},
+    {NULL, NULL, 0, NULL}
+};
+
+PyMODINIT_FUNC
+#if PY_MAJOR_VERSION >= 3
+PyInit__test(void)
+#else
+init_test(void)
+#endif
+{
+	#if PY_MAJOR_VERSION >= 3
+		PyObject *module;
+		static struct PyModuleDef moduledef = {
+			PyModuleDef_HEAD_INIT,
+			"_test",             /* m_name */
+			module_docstring,    /* m_doc */
+			-1,                  /* m_size */
+			module_methods,      /* m_methods */
+			NULL,                /* m_reload */
+			NULL,                /* m_traverse */
+			NULL,                /* m_clear */
+			NULL,                /* m_free */
+		};
+	#endif
+
+	#if PY_MAJOR_VERSION >= 3
+		module = PyModule_Create(&moduledef);
+		if (!module)
+			return NULL;
+		/* Load `numpy` functionality. */
+		import_array();
+		return module;
+	#else
+	    PyObject *m = Py_InitModule3("_test", module_methods, module_docstring);
+		if (m == NULL)
+			return;
+		/* Load `numpy` functionality. */
+		import_array();
+	#endif
+}
+
+static PyObject *test_test(PyObject *self, PyObject *args)
+{
+    double m, b;
+    PyObject *x_obj, *y_obj, *yerr_obj;
+
+    /* Parse the input tuple */
+    if (!PyArg_ParseTuple(args, "ddOOO", &m, &b, &x_obj, &y_obj,
+                                        &yerr_obj))
+        return NULL;
+
+    /* Interpret the input objects as numpy arrays. */
+    PyObject *x_array = PyArray_FROM_OTF(x_obj, NPY_DOUBLE, NPY_IN_ARRAY);
+    PyObject *y_array = PyArray_FROM_OTF(y_obj, NPY_DOUBLE, NPY_IN_ARRAY);
+    PyObject *yerr_array = PyArray_FROM_OTF(yerr_obj, NPY_DOUBLE,
+                                            NPY_IN_ARRAY);
+
+    /* If that didn't work, throw an exception. */
+    if (x_array == NULL || y_array == NULL || yerr_array == NULL) {
+        Py_XDECREF(x_array);
+        Py_XDECREF(y_array);
+        Py_XDECREF(yerr_array);
+        return NULL;
+    }
+
+    /* How many data points are there? */
+    int N = (int)PyArray_DIM(x_array, 0);
+
+    /* Get pointers to the data as C-types. */
+    double *x    = (double*)PyArray_DATA(x_array);
+    double *y    = (double*)PyArray_DATA(y_array);
+    double *yerr = (double*)PyArray_DATA(yerr_array);
+
+    /* Call the external C function to compute the chi-squared. */
+    double value = test(m, b, x, y, yerr, N);
+
+    /* Clean up. */
+    Py_DECREF(x_array);
+    Py_DECREF(y_array);
+    Py_DECREF(yerr_array);
+
+    if (value < 0.0) {
+        PyErr_SetString(PyExc_RuntimeError,
+                    "Chi-squared returned an impossible value.");
+        return NULL;
+    }
+
+    /* Build the output tuple */
+    PyObject *ret = Py_BuildValue("d", value);
+    return ret;
+}

c_src/polar.c

@@ -0,0 +1,10 @@
+#include "polar.h"
+#include "math.h"
+
+double polar_distance(double r1, double r2, double theta1, double theta2) {
+    double d;
+
+    d = sqrt(pow(r1,2) + pow(r2,2) - 2*r1*r2*cos(theta2-theta1));
+
+    return d;
+}

c_src/polar.h

@@ -0,0 +1 @@
+double polar_distance(double r1, double r2, double theta1, double theta2);

c_src/test.c

@@ -0,0 +1,13 @@
+#include "test.h"
+
+double test(double m, double b, double *x, double *y, double *yerr, int N) {
+    int n;
+    double result = 0.0, diff;
+
+    for (n = 0; n < N; n++) {
+        diff = (y[n] - (m * x[n] + b)) / yerr[n];
+        result += diff * diff;
+    }
+
+    return result;
+}

c_src/test.h

@@ -0,0 +1 @@
+double test(double m, double b, double *x, double *y, double *yerr, int N);