Split inverse into backward and inverse

src/complex.rs

@@ -14,16 +14,23 @@ pub fn forward(data: &mut [c64]) {
     perform(data, n, false);
 }
 
+/// Perform the backward transform.
+///
+/// The number of points should be a power of two.
+pub fn backward(data: &mut [c64]) {
+    let n = power_of_two!(data);
+    rearrange(data, n);
+    perform(data, n, true);
+}
+
 /// Perform the inverse transform.
 ///
 /// The number of points should be a power of two.
-pub fn inverse(data: &mut [c64], scaling: bool) {
+pub fn inverse(data: &mut [c64]) {
     let n = power_of_two!(data);
     rearrange(data, n);
     perform(data, n, true);
-    if scaling {
-        scale(data, n);
-    }
+    scale(data, n);
 }
 
 fn rearrange(data: &mut [c64], n: usize) {

src/real.rs

@@ -28,14 +28,24 @@ pub fn forward(data: &mut [f64]) {
     compose(data, n, false);
 }
 
+/// Perform the backward transform.
+///
+/// The number of points should be a power of two. The data should be packed as
+/// described in `real::forward`.
+pub fn backward(data: &mut [f64]) {
+    let (data, n) = reinterpret!(data);
+    compose(data, n, true);
+    ::complex::backward(data);
+}
+
 /// Perform the inverse transform.
 ///
 /// The number of points should be a power of two. The data should be packed as
 /// described in `real::forward`.
-pub fn inverse(data: &mut [f64], scaling: bool) {
+pub fn inverse(data: &mut [f64]) {
     let (data, n) = reinterpret!(data);
     compose(data, n, true);
-    ::complex::inverse(data, scaling);
+    ::complex::inverse(data);
 }
 
 /// Unpack a compressed representation produced by `real::forward`.

tests/lib.rs

@@ -16,7 +16,7 @@ fn complex_forward() {
 #[test]
 fn complex_inverse() {
     let mut data = fixtures::FREQUENCY_DATA_FOR_COMPLEX.to_vec();
-    fft::complex::inverse(as_c64_mut(&mut data), true);
+    fft::complex::inverse(as_c64_mut(&mut data));
     assert::close(&data, &fixtures::TIME_DATA[..], 1e-14);
 }
 
@@ -39,7 +39,7 @@ fn real_forward() {
 #[test]
 fn real_inverse() {
     let mut data = fixtures::FREQUENCY_DATA_FOR_REAL.to_vec();
-    fft::real::inverse(&mut data, true);
+    fft::real::inverse(&mut data);
     assert::close(&data, &fixtures::TIME_DATA[..], 1e-14);
 }