Add rustfmt to the CI pipeline

.travis.yml

@@ -18,10 +18,16 @@ before_cache: |
   if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
     RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-tarpaulin
   fi
-script:
-- cargo clean
-- cargo build
-- cargo test
+before_script:
+- rustup component add rustfmt
+# As a result of https://github.com/travis-ci/travis-ci/issues/1066, we run
+# everything in one large command instead of multiple commands.
+# In this way, the build stops immediately if one of the commands fails.
+script: |
+  cargo clean &&
+  cargo fmt --all -- --check &&
+  cargo build &&
+  cargo test
 after_success: |
   if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
     cargo tarpaulin --out Xml

src/correlation.rs

@@ -131,14 +131,15 @@ where
     {
         let observation_axis = Axis(1);
         let n_observations = A::from_usize(self.len_of(observation_axis)).unwrap();
-        let dof =
-            if ddof >= n_observations {
-                panic!("`ddof` needs to be strictly smaller than the \
-                        number of observations provided for each \
-                        random variable!")
-            } else {
-                n_observations - ddof
-            };
+        let dof = if ddof >= n_observations {
+            panic!(
+                "`ddof` needs to be strictly smaller than the \
+                 number of observations provided for each \
+                 random variable!"
+            )
+        } else {
+            n_observations - ddof
+        };
         let mean = self.mean_axis(observation_axis);
         let denoised = self - &mean.insert_axis(observation_axis);
         let covariance = denoised.dot(&denoised.t());
@@ -156,7 +157,9 @@ where
         // observation per random variable (or no observations at all)
         let ddof = -A::one();
         let cov = self.cov(ddof);
-        let std = self.std_axis(observation_axis, ddof).insert_axis(observation_axis);
+        let std = self
+            .std_axis(observation_axis, ddof)
+            .insert_axis(observation_axis);
         let std_matrix = std.dot(&std.t());
         // element-wise division
         cov / std_matrix
@@ -167,10 +170,10 @@ where
 mod cov_tests {
     use super::*;
     use ndarray::array;
+    use ndarray_rand::RandomExt;
     use quickcheck::quickcheck;
     use rand;
     use rand::distributions::Uniform;
-    use ndarray_rand::RandomExt;
 
     quickcheck! {
         fn constant_random_variables_have_zero_covariance_matrix(value: f64) -> bool {
@@ -200,10 +203,7 @@ mod cov_tests {
     fn test_invalid_ddof() {
         let n_random_variables = 3;
         let n_observations = 4;
-        let a = Array::random(
-            (n_random_variables, n_observations),
-            Uniform::new(0., 10.)
-        );
+        let a = Array::random((n_random_variables, n_observations), Uniform::new(0., 10.));
         let invalid_ddof = (n_observations as f64) + rand::random::<f64>().abs();
         a.cov(invalid_ddof);
     }
@@ -235,55 +235,46 @@ mod cov_tests {
     #[test]
     fn test_covariance_for_random_array() {
         let a = array![
-            [ 0.72009497,  0.12568055,  0.55705966,  0.5959984 ,  0.69471457],
-            [ 0.56717131,  0.47619486,  0.21526298,  0.88915366,  0.91971245],
-            [ 0.59044195,  0.10720363,  0.76573717,  0.54693675,  0.95923036],
-            [ 0.24102952,  0.131347,  0.11118028,  0.21451351,  0.30515539],
-            [ 0.26952473,  0.93079841,  0.8080893 ,  0.42814155,  0.24642258]
+            [0.72009497, 0.12568055, 0.55705966, 0.5959984, 0.69471457],
+            [0.56717131, 0.47619486, 0.21526298, 0.88915366, 0.91971245],
+            [0.59044195, 0.10720363, 0.76573717, 0.54693675, 0.95923036],
+            [0.24102952, 0.131347, 0.11118028, 0.21451351, 0.30515539],
+            [0.26952473, 0.93079841, 0.8080893, 0.42814155, 0.24642258]
         ];
         let numpy_covariance = array![
-            [ 0.05786248,  0.02614063,  0.06446215,  0.01285105, -0.06443992],
-            [ 0.02614063,  0.08733569,  0.02436933,  0.01977437, -0.06715555],
-            [ 0.06446215,  0.02436933,  0.10052129,  0.01393589, -0.06129912],
-            [ 0.01285105,  0.01977437,  0.01393589,  0.00638795, -0.02355557],
-            [-0.06443992, -0.06715555, -0.06129912, -0.02355557,  0.09909855]
+            [0.05786248, 0.02614063, 0.06446215, 0.01285105, -0.06443992],
+            [0.02614063, 0.08733569, 0.02436933, 0.01977437, -0.06715555],
+            [0.06446215, 0.02436933, 0.10052129, 0.01393589, -0.06129912],
+            [0.01285105, 0.01977437, 0.01393589, 0.00638795, -0.02355557],
+            [
+                -0.06443992,
+                -0.06715555,
+                -0.06129912,
+                -0.02355557,
+                0.09909855
+            ]
         ];
         assert_eq!(a.ndim(), 2);
-        assert!(
-            a.cov(1.).all_close(
-                &numpy_covariance,
-                1e-8
-            )
-        );
+        assert!(a.cov(1.).all_close(&numpy_covariance, 1e-8));
     }
 
     #[test]
     #[should_panic]
     // We lose precision, hence the failing assert
     fn test_covariance_for_badly_conditioned_array() {
-        let a: Array2<f64> = array![
-            [ 1e12 + 1.,  1e12 - 1.],
-            [ 1e-6 + 1e-12,  1e-6 - 1e-12],
-        ];
-        let expected_covariance = array![
-            [2., 2e-12], [2e-12, 2e-24]
-        ];
-        assert!(
-            a.cov(1.).all_close(
-                &expected_covariance,
-                1e-24
-            )
-        );
+        let a: Array2<f64> = array![[1e12 + 1., 1e12 - 1.], [1e-6 + 1e-12, 1e-6 - 1e-12],];
+        let expected_covariance = array![[2., 2e-12], [2e-12, 2e-24]];
+        assert!(a.cov(1.).all_close(&expected_covariance, 1e-24));
     }
 }
 
 #[cfg(test)]
 mod pearson_correlation_tests {
     use super::*;
     use ndarray::array;
+    use ndarray_rand::RandomExt;
     use quickcheck::quickcheck;
     use rand::distributions::Uniform;
-    use ndarray_rand::RandomExt;
 
     quickcheck! {
         fn output_matrix_is_symmetric(bound: f64) -> bool {
@@ -337,19 +328,14 @@ mod pearson_correlation_tests {
             [0.26979716, 0.20887228, 0.95454999, 0.96290785]
         ];
         let numpy_corrcoeff = array![
-            [ 1.        ,  0.38089376,  0.08122504, -0.59931623,  0.1365648 ],
-            [ 0.38089376,  1.        ,  0.80918429, -0.52615195,  0.38954398],
-            [ 0.08122504,  0.80918429,  1.        ,  0.07134906, -0.17324776],
-            [-0.59931623, -0.52615195,  0.07134906,  1.        , -0.8743213 ],
-            [ 0.1365648 ,  0.38954398, -0.17324776, -0.8743213 ,  1.        ]
+            [1., 0.38089376, 0.08122504, -0.59931623, 0.1365648],
+            [0.38089376, 1., 0.80918429, -0.52615195, 0.38954398],
+            [0.08122504, 0.80918429, 1., 0.07134906, -0.17324776],
+            [-0.59931623, -0.52615195, 0.07134906, 1., -0.8743213],
+            [0.1365648, 0.38954398, -0.17324776, -0.8743213, 1.]
         ];
         assert_eq!(a.ndim(), 2);
-        assert!(
-            a.pearson_correlation().all_close(
-                &numpy_corrcoeff,
-                1e-7
-            )
-        );
+        assert!(a.pearson_correlation().all_close(&numpy_corrcoeff, 1e-7));
     }
 
 }

src/histogram/bins.rs

@@ -33,7 +33,6 @@ pub struct Edges<A: Ord> {
 }
 
 impl<A: Ord> From<Vec<A>> for Edges<A> {
-
     /// Get an `Edges` instance from a `Vec<A>`:
     /// the vector will be sorted in increasing order
     /// using an unstable sorting algorithm and duplicates
@@ -89,7 +88,7 @@ impl<A: Ord + Clone> From<Array1<A>> for Edges<A> {
     }
 }
 
-impl<A: Ord> Index<usize> for Edges<A>{
+impl<A: Ord> Index<usize> for Edges<A> {
     type Output = A;
 
     /// Get the `i`-th edge.
@@ -182,13 +181,11 @@ impl<A: Ord> Edges<A> {
         match self.edges.binary_search(value) {
             Ok(i) if i == n_edges - 1 => None,
             Ok(i) => Some((i, i + 1)),
-            Err(i) => {
-                match i {
-                    0 => None,
-                    j if j == n_edges => None,
-                    j => Some((j - 1, j)),
-                }
-            }
+            Err(i) => match i {
+                0 => None,
+                j if j == n_edges => None,
+                j => Some((j - 1, j)),
+            },
         }
     }
 
@@ -309,18 +306,14 @@ impl<A: Ord> Bins<A> {
     /// );
     /// ```
     pub fn range_of(&self, value: &A) -> Option<Range<A>>
-        where
-            A: Clone,
+    where
+        A: Clone,
     {
         let edges_indexes = self.edges.indices_of(value);
-        edges_indexes.map(
-            |(left, right)| {
-                Range {
-                    start: self.edges[left].clone(),
-                    end: self.edges[right].clone(),
-                }
-            }
-        )
+        edges_indexes.map(|(left, right)| Range {
+            start: self.edges[left].clone(),
+            end: self.edges[right].clone(),
+        })
     }
 
     /// Get the `i`-th bin.
@@ -341,7 +334,7 @@ impl<A: Ord> Bins<A> {
     /// );
     /// ```
     pub fn index(&self, index: usize) -> Range<A>
-        where
+    where
         A: Clone,
     {
         // It was not possible to implement this functionality
@@ -350,7 +343,7 @@ impl<A: Ord> Bins<A> {
         // Index, in fact, forces you to return a reference.
         Range {
             start: self.edges[index].clone(),
-            end: self.edges[index+1].clone(),
+            end: self.edges[index + 1].clone(),
         }
     }
 }

src/histogram/grid.rs

@@ -1,8 +1,8 @@
 use super::bins::Bins;
 use super::strategies::BinsBuildingStrategy;
-use std::ops::Range;
 use itertools::izip;
-use ndarray::{ArrayBase, Data, Ix1, Ix2, Axis};
+use ndarray::{ArrayBase, Axis, Data, Ix1, Ix2};
+use std::ops::Range;
 
 /// A `Grid` is a partition of a rectangular region of an *n*-dimensional
 /// space—e.g. [*a*<sub>0</sub>, *b*<sub>0</sub>) × ⋯ × [*a*<sub>*n*−1</sub>,
@@ -72,7 +72,6 @@ pub struct Grid<A: Ord> {
 }
 
 impl<A: Ord> From<Vec<Bins<A>>> for Grid<A> {
-
     /// Get a `Grid` instance from a `Vec<Bins<A>>`.
     ///
     /// The `i`-th element in `Vec<Bins<A>>` represents the 1-dimensional
@@ -113,9 +112,14 @@ impl<A: Ord> Grid<A> {
     where
         S: Data<Elem = A>,
     {
-        assert_eq!(point.len(), self.ndim(),
-                   "Dimension mismatch: the point has {:?} dimensions, the grid \
-                   expected {:?} dimensions.", point.len(), self.ndim());
+        assert_eq!(
+            point.len(),
+            self.ndim(),
+            "Dimension mismatch: the point has {:?} dimensions, the grid \
+             expected {:?} dimensions.",
+            point.len(),
+            self.ndim()
+        );
         point
             .iter()
             .zip(self.projections.iter())
@@ -132,9 +136,14 @@ impl<A: Ord + Clone> Grid<A> {
     /// **Panics** if at least one among `(i_0, ..., i_{n-1})` is out of bounds on the respective
     /// coordinate axis - i.e. if there exists `j` such that `i_j >= self.projections[j].len()`.
     pub fn index(&self, index: &[usize]) -> Vec<Range<A>> {
-        assert_eq!(index.len(), self.ndim(),
-                   "Dimension mismatch: the index has {0:?} dimensions, the grid \
-                   expected {1:?} dimensions.", index.len(), self.ndim());
+        assert_eq!(
+            index.len(),
+            self.ndim(),
+            "Dimension mismatch: the index has {0:?} dimensions, the grid \
+             expected {1:?} dimensions.",
+            index.len(),
+            self.ndim()
+        );
         izip!(&self.projections, index)
             .map(|(bins, &i)| bins.index(i))
             .collect()
@@ -164,7 +173,7 @@ where
     /// [`strategy`]: strategies/index.html
     pub fn from_array<S>(array: &ArrayBase<S, Ix2>) -> Self
     where
-        S: Data<Elem=A>,
+        S: Data<Elem = A>,
     {
         let bin_builders = array
             .axis_iter(Axis(1))

src/histogram/histograms.rs

@@ -1,7 +1,7 @@
+use super::errors::BinNotFound;
+use super::grid::Grid;
 use ndarray::prelude::*;
 use ndarray::Data;
-use super::grid::Grid;
-use super::errors::BinNotFound;
 
 /// Histogram data structure.
 pub struct Histogram<A: Ord> {
@@ -58,8 +58,8 @@ impl<A: Ord> Histogram<A> {
             Some(bin_index) => {
                 self.counts[&*bin_index] += 1;
                 Ok(())
-            },
-            None => Err(BinNotFound)
+            }
+            None => Err(BinNotFound),
         }
     }
 
@@ -82,8 +82,8 @@ impl<A: Ord> Histogram<A> {
 
 /// Extension trait for `ArrayBase` providing methods to compute histograms.
 pub trait HistogramExt<A, S>
-    where
-        S: Data<Elem = A>,
+where
+    S: Data<Elem = A>,
 {
     /// Returns the [histogram](https://en.wikipedia.org/wiki/Histogram)
     /// for a 2-dimensional array of points `M`.
@@ -145,17 +145,16 @@ pub trait HistogramExt<A, S>
     /// # }
     /// ```
     fn histogram(&self, grid: Grid<A>) -> Histogram<A>
-        where
-            A: Ord;
+    where
+        A: Ord;
 }
 
 impl<A, S> HistogramExt<A, S> for ArrayBase<S, Ix2>
-    where
-        S: Data<Elem = A>,
-        A: Ord,
+where
+    S: Data<Elem = A>,
+    A: Ord,
 {
-    fn histogram(&self, grid: Grid<A>) -> Histogram<A>
-    {
+    fn histogram(&self, grid: Grid<A>) -> Histogram<A> {
         let mut histogram = Histogram::new(grid);
         for point in self.axis_iter(Axis(0)) {
             let _ = histogram.add_observation(&point);

src/histogram/mod.rs

@@ -1,10 +1,10 @@
 //! Histogram functionalities.
-pub use self::histograms::{Histogram, HistogramExt};
-pub use self::bins::{Edges, Bins};
+pub use self::bins::{Bins, Edges};
 pub use self::grid::{Grid, GridBuilder};
+pub use self::histograms::{Histogram, HistogramExt};
 
-mod histograms;
 mod bins;
-pub mod strategies;
-mod grid;
 pub mod errors;
+mod grid;
+mod histograms;
+pub mod strategies;