Avoid using vec![]

Author: cschwan

pineappl/src/packed_array.rs

@@ -28,9 +28,9 @@ impl<T: Copy + Default + PartialEq> PackedArray<T> {
     #[must_use]
     pub const fn new(shape: Vec<usize>) -> Self {
         Self {
-            entries: vec![],
-            start_indices: vec![],
-            lengths: vec![],
+            entries: Vec::new(),
+            start_indices: Vec::new(),
+            lengths: Vec::new(),
             shape,
         }
     }

pineappl_capi/src/lib.rs

@@ -445,14 +445,14 @@ pub unsafe extern "C" fn pineappl_grid_convolve_with_one(
     let mut xfx = |id, x, q2| xfx(id, x, q2, state);
     let mut als = |q2| alphas(q2, state);
     let order_mask = if order_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }.to_owned()
+        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }
     };
     let channel_mask = if channel_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }.to_vec()
+        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }
     };
     let results = unsafe { slice::from_raw_parts_mut(results, grid.bin_info().bins()) };
     let mut convolution_cache = ConvolutionCache::new(
@@ -463,7 +463,7 @@ pub unsafe extern "C" fn pineappl_grid_convolve_with_one(
 
     results.copy_from_slice(&grid.convolve(
         &mut convolution_cache,
-        &order_mask,
+        order_mask,
         &[],
         &channel_mask,
         &[(xi_ren, xi_fac, 1.0)],
@@ -511,14 +511,14 @@ pub unsafe extern "C" fn pineappl_grid_convolve_with_two(
     let mut xfx2 = |id, x, q2| xfx2(id, x, q2, state);
     let mut als = |q2| alphas(q2, state);
     let order_mask = if order_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }.to_vec()
+        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }
     };
     let channel_mask = if channel_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }.to_vec()
+        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }
     };
     let results = unsafe { slice::from_raw_parts_mut(results, grid.bin_info().bins()) };
     let mut convolution_cache = ConvolutionCache::new(
@@ -532,7 +532,7 @@ pub unsafe extern "C" fn pineappl_grid_convolve_with_two(
 
     results.copy_from_slice(&grid.convolve(
         &mut convolution_cache,
-        &order_mask,
+        order_mask,
         &[],
         &channel_mask,
         &[(xi_ren, xi_fac, 1.0)],
@@ -1699,15 +1699,15 @@ pub unsafe extern "C" fn pineappl_grid_convolve(
     let grid = unsafe { &*grid };
 
     let order_mask = if order_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }.to_owned()
+        unsafe { slice::from_raw_parts(order_mask, grid.orders().len()) }
     };
 
     let channel_mask = if channel_mask.is_null() {
-        vec![]
+        &[]
     } else {
-        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }.to_vec()
+        unsafe { slice::from_raw_parts(channel_mask, grid.channels().len()) }
     };
 
     let bin_indices = if bin_indices.is_null() {
@@ -1746,9 +1746,9 @@ pub unsafe extern "C" fn pineappl_grid_convolve(
 
     results.copy_from_slice(&grid.convolve(
         &mut convolution_cache,
-        &order_mask,
+        order_mask,
         bin_indices,
-        &channel_mask,
+        channel_mask,
         mu_scales,
     ));
 }

pineappl_cli/src/import.rs

@@ -133,7 +133,7 @@ fn convert_fastnlo(
 fn convert_fktable(input: &Path) -> Result<(&'static str, Grid, Vec<f64>, usize)> {
     let fktable = fktable::convert_fktable(input)?;
 
-    Ok(("fktable", fktable, vec![], 1))
+    Ok(("fktable", fktable, Vec::new(), 1))
 }
 
 #[cfg(not(feature = "fktable"))]
@@ -195,7 +195,7 @@ fn fnlo_mu_possible_values() -> Vec<&'static str> {
 
 #[cfg(not(feature = "fastnlo"))]
 const fn fnlo_mu_possible_values() -> Vec<&'static str> {
-    vec![]
+    Vec::new()
 }
 
 /// Converts APPLgrid/fastNLO/FastKernel files to PineAPPL grids.

pineappl_cli/src/plot.rs

@@ -379,7 +379,7 @@ impl Subcommand for Opts {
                     .collect();
 
                 let channels = if matches!(mode, ConvoluteMode::Asymmetry) {
-                    vec![]
+                    Vec::new()
                 } else {
                     let mut channels: Vec<_> = (0..grid.channels().len())
                         .map(|channel| {
@@ -692,9 +692,9 @@ metadata = {{
                 // TODO: convert this into an error
                 .unwrap();
 
-            let mut x1_vals = vec![];
-            let mut x2_vals = vec![];
-            let mut vals = vec![];
+            let mut x1_vals = Vec::new();
+            let mut x2_vals = Vec::new();
+            let mut vals = Vec::new();
 
             for (((ix1, ix2), &one), &two) in res1.indexed_iter().zip(res2.iter()) {
                 if one == 0.0 {

pineappl_cli/src/pull.rs

@@ -206,7 +206,7 @@ impl Subcommand for Opts {
                 };
 
             let mut pull_tuples = if self.limit == 0 {
-                vec![]
+                Vec::new()
             } else {
                 let channel_results1 = channel_results(
                     self.conv_funs1.members[self.pull_from],