+// Functions that are inline in filter.h
+
+
+// sinc Return sin(x)/x function
+// v = sinc (x, mult)
+// Calculates sin(x * mult) / x;
+
+// integral_abscos Returns integral of u*cos(u)
+//
+// q = integral_abscos (u, w)
+// double q Integral value
+// double u Integration variable
+// double w Upper integration boundary
+// Returns the value of integral of u*cos(u)*dV for V = 0 to w