Add binomial calculation and tests.
Change-Id: I7a758d098c7af53e7b719461aa5d0e8de240052d
diff --git a/frc971/control_loops/binomial.h b/frc971/control_loops/binomial.h
new file mode 100644
index 0000000..4f4c4dc
--- /dev/null
+++ b/frc971/control_loops/binomial.h
@@ -0,0 +1,24 @@
+#ifndef FRC971_CONTROL_LOOPS_BINOMIAL_H_
+#define FRC971_CONTROL_LOOPS_BINOMIAL_H_
+
+namespace frc971 {
+namespace control_loops {
+
+// Computes the factorial of n
+constexpr double Factorial(int n) {
+ if (n <= 1) {
+ return 1.0;
+ } else {
+ return Factorial(n - 1) * n;
+ }
+}
+
+// Computes the binomial coefficients. n choose k.
+constexpr double Binomial(int n, int k) {
+ return Factorial(n) / (Factorial(k) * Factorial(n - k));
+}
+
+} // namespace control_loops
+} // namespace frc971
+
+#endif // FRC971_CONTROL_LOOPS_BINOMIAL_H_