Merge pull request #465 from dirac-institute/psf_checks

Add some basic checks and tests for PSF

src/kbmod/search/psf.cpp

@@ -9,6 +9,10 @@ PSF::PSF() : kernel(1, 1.0) {
 }
 
 PSF::PSF(float stdev) {
+    if (stdev <= 0.0) {
+        throw std::runtime_error("PSF stdev must be > 0.0.");
+    }
+
     width = stdev;
     float simple_gauss[MAX_KERNEL_RADIUS];
     double psf_coverage = 0.0;
@@ -28,7 +32,7 @@ PSF::PSF(float stdev) {
         i++;
     }
 
-    radius = i - 1;  // This value is good for
+    radius = i - 1;
     dim = 2 * radius + 1;
 
     // Create 2D gaussain by multiplying with itself
@@ -155,6 +159,7 @@ static void psf_bindings(py::module& m) {
             .def(py::init<float>())
             .def(py::init<py::array_t<float>>())
             .def(py::init<psf&>())
+            .def("__str__", &psf::print)
             .def("set_array", &psf::set_array, pydocs::DOC_PSF_set_array)
             .def("get_std", &psf::get_std, pydocs::DOC_PSF_get_std)
             .def("get_sum", &psf::get_sum, pydocs::DOC_PSF_get_sum)

src/kbmod/search/pydocs/psf_docs.h

@@ -8,18 +8,22 @@ static const auto DOC_PSF = R"doc(
   Parameters
   ----------
   stdev : `float`, optional
-      Standard deviation of the Gaussian PSF.
+      Standard deviation of the Gaussian PSF. Must be > 0.0.
   psf : `PSF`, optional
       Another PSF object.
   arr : `numpy.array`, optional
       A realization of the PSF.
 
-   Notes
-   -----
-   When instantiated with another `psf` object, returns its copy.
-   When instantiated with an array-like object, that array must be
-   a square matrix and have an odd number of dimensions. Only one
-   of the arguments is required.
+  Notes
+  -----
+  When instantiated with another `psf` object, returns its copy.
+  When instantiated with an array-like object, that array must be
+  a square matrix and have an odd number of dimensions. Only one
+  of the arguments is required.
+
+  Raises
+  ------
+  Raises a ``RuntimeError`` when given an invalid stdev.
   )doc";
 
 static const auto DOC_PSF_set_array = R"doc(

tests/test_psf.py

@@ -19,6 +19,14 @@ def test_make_noop(self):
         self.assertEqual(len(kernel0), 1)
         self.assertEqual(kernel0[0], 1.0)
 
+    def test_make_invalud(self):
+        # Raise an error if creating a PSF with a negative stdev.
+        self.assertRaises(RuntimeError, PSF, -1.0)
+
+    def test_to_string(self):
+        result = self.psf_list[0].__str__()
+        self.assertGreater(len(result), 1)
+
     def test_make_and_copy(self):
         psf1 = PSF(1.0)
         self.assertEqual(psf1.get_size(), 25)