diff --git a/src/math/pifft_p.h b/src/math/pifft_p.h
index cdedf9fd..0b20f588 100644
--- a/src/math/pifft_p.h
+++ b/src/math/pifft_p.h
@@ -87,13 +87,13 @@ public:
 		return v_out;
 	}
 	const PIVector<complex<T> > & calcFFTinverse(const PIVector<complex<T> > & in) {
-		if (prepare != PlanParams(in.size(), fo_complex)) {
+		if (prepare != PlanParams(in.size(), fo_inverse)) {
 			newVec(p_in, in.size());
 			newVec(p_out, in.size());
 			piCout << "[PIFFTW]" << "creating plan";
 			p_createPlan_c2c_1d(plan, in.size(), p_in, p_out, FFTW_BACKWARD, FFTW_ESTIMATE | FFTW_DESTROY_INPUT);
 			v_out.resize(in.size());
-			prepare = PlanParams(in.size(), fo_complex);
+			prepare = PlanParams(in.size(), fo_inverse);
 		}
 		memcpy(p_in, in.data(), sizeof(complex<T>) * in.size());
 		p_executePlan(plan);