Resolve "Check that element length is long relative to a time step"

Closes #349 (closed)

src/Algorithms/OrbitThreader.cpp

@@ -114,23 +114,24 @@ void OrbitThreader::checkElementLengths(const std::set<std::shared_ptr<Component
         return;
     }
     double driftLength = Physics::c * stepSizes_m.getdT() * p_m(2) / Util::getGamma(p_m);
-    for (const std::shared_ptr<Component> field: fields) {
+    for (const std::shared_ptr<Component> field : fields) {
         ElementBase::ElementType type = field->getType();
+        double length = field->getElementLength();
+        int numSteps = 10;
         if (type == ElementBase::MONITOR ||
             type == ElementBase::SOURCE ||
             type == ElementBase::DRIFT ||
             type == ElementBase::MARKER ||
-            type == ElementBase::SEPTUM ||
             type == ElementBase::STRIPPER) {
-            continue;
+            numSteps = 1;
         }
-        double length = field->getElementLength();
-        if (length < 10 * driftLength) {
+        if (length < numSteps * driftLength) {
             throw OpalException("OrbitThreader::checkElementLengths",
-                                "The element '" + field->getName() +
-                                "' is too short compared to the size of the time step\n" +
+                                "The time step is too long compared to the length of the\n"
+                                "element '" + field->getName() + "'\n" +
                                 "The length of the element is: " + std::to_string(length) + "\n"
-                                "The distance the particles drift in 10 time steps is: " + std::to_string(10 * driftLength));
+                                "The distance the particles drift in " + std::string(numSteps) +
+                                " time step(s) is: " + std::to_string(numSteps * driftLength));
         }
     }
 }
@@ -478,4 +479,4 @@ double OrbitThreader::computeDriftLengthToBoundingBox(const std::set<std::shared
     }
 
     return std::numeric_limits<double>::max();
-}
\ No newline at end of file
+}