From 9c012f414558b7ee500c5bb18df4f299a631db68 Mon Sep 17 00:00:00 2001
From: peterkrack <peter.krack@yahoo.de>
Date: Fri, 14 Nov 2025 16:43:26 +0100
Subject: [PATCH 1/5] add delete bins to capi.

---
 pineappl_capi/src/lib.rs | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/pineappl_capi/src/lib.rs b/pineappl_capi/src/lib.rs
index b2ef04a47..c5f18748c 100644
--- a/pineappl_capi/src/lib.rs
+++ b/pineappl_capi/src/lib.rs
@@ -847,7 +847,7 @@ pub unsafe extern "C" fn pineappl_grid_read(filename: *const c_char) -> Box<Grid
 ///
 /// # Safety
 ///
-/// The parameter `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
+/// The `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
 /// `pineappl_grid_read`.
 ///
 /// # Panics
@@ -860,6 +860,27 @@ pub unsafe extern "C" fn pineappl_grid_merge_bins(grid: *mut Grid, from: usize,
     grid.merge_bins(from..to).unwrap();
 }
 
+/// Deletes bins with the corresponding `bin_indices`. Repeated indices and indices larger or
+/// equal the bin length are ignored.
+///
+/// # Safety
+///
+///  The parameter `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
+/// `pineappl_grid_read`.
+///
+/// # Panics
+///
+/// TODO
+#[no_mangle]
+pub unsafe extern "C" fn pineappl_grid_delete_bins(grid: *mut Grid, 
+                                                   bin_indices_ptr: *const usize, 
+                                                   bin_indices_len: usize) {
+    let grid = unsafe { &mut *grid };
+    let bin_indices = unsafe { std::slice::from_raw_parts(bin_indices_ptr, bin_indices_len) };
+    grid.delete_bins(bin_indices);
+
+}
+
 /// Merges `other` into `grid` and subsequently deletes `other`.
 ///
 /// # Safety

From 9a9148e2065f820e22635e517543122e83d74d4a Mon Sep 17 00:00:00 2001
From: peterkrack <peter.krack@yahoo.de>
Date: Mon, 17 Nov 2025 15:28:59 +0100
Subject: [PATCH 2/5] resolve requested small changes.

---
 pineappl_capi/src/lib.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pineappl_capi/src/lib.rs b/pineappl_capi/src/lib.rs
index c5f18748c..22ec18b2f 100644
--- a/pineappl_capi/src/lib.rs
+++ b/pineappl_capi/src/lib.rs
@@ -847,7 +847,7 @@ pub unsafe extern "C" fn pineappl_grid_read(filename: *const c_char) -> Box<Grid
 ///
 /// # Safety
 ///
-/// The `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
+/// The parameter `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
 /// `pineappl_grid_read`.
 ///
 /// # Panics
@@ -866,7 +866,8 @@ pub unsafe extern "C" fn pineappl_grid_merge_bins(grid: *mut Grid, from: usize,
 /// # Safety
 ///
 ///  The parameter `grid` must be valid `Grid` object created by either `pineappl_grid_new` or
-/// `pineappl_grid_read`.
+///  `pineappl_grid_read`.
+///  The parameter `bin_indices_ptr` must be an array of size `bin_indices_len`.
 ///
 /// # Panics
 ///
@@ -878,7 +879,6 @@ pub unsafe extern "C" fn pineappl_grid_delete_bins(grid: *mut Grid,
     let grid = unsafe { &mut *grid };
     let bin_indices = unsafe { std::slice::from_raw_parts(bin_indices_ptr, bin_indices_len) };
     grid.delete_bins(bin_indices);
-
 }
 
 /// Merges `other` into `grid` and subsequently deletes `other`.

From 07fa53b0f7887f6d406370c544301ea556d89666 Mon Sep 17 00:00:00 2001
From: peterkrack <peter.krack@yahoo.de>
Date: Mon, 17 Nov 2025 18:59:08 +0100
Subject: [PATCH 3/5] use delete_bins in advanced_filling.cpp example.

---
 examples/cpp/advanced-filling.cpp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/examples/cpp/advanced-filling.cpp b/examples/cpp/advanced-filling.cpp
index 7b8be66c1..4e330355e 100644
--- a/examples/cpp/advanced-filling.cpp
+++ b/examples/cpp/advanced-filling.cpp
@@ -173,6 +173,37 @@ int main() {
 
     pineappl_grid_write(grid, "advanced-filling.pineappl.lz4");
 
+    //-----------------------------------------------------------------------//
+    
+    // Remove the bins for which the convolution is zero.
+    std::vector<uintptr_t> zero_indices;
+    zero_indices.reserve(dxsec.size());
+    for (size_t i = 0; i < dxsec.size(); ++i) {
+        if (dxsec[i] == 0.0) {
+           zero_indices.push_back(static_cast<uintptr_t>(i));
+        }
+    }
+    pineappl_grid_delete_bins(grid, zero_indices.data(), zero_indices.size());
+
+    std::vector<double> dxsec_no_zeros(pineappl_grid_bin_count(grid));
+    pineappl_grid_convolve(grid, xfx, alphas, pdf_states, pdf.get(), order_mask, channel_mask,
+        nullptr, 1, mmu_scales.data(), dxsec_no_zeros.data());
+
+    // Print table header
+    std::cout << " " << std::endl;
+    std::cout << std::setw(10) << "bin left"
+              << std::setw(12) << "bin right"
+              << std::setw(15) << "dsig/dx" << std::endl;
+    std::cout << std::string(37, '-') << std::endl;
+
+    // Loop through bins and print results
+    for (size_t i = 0; i < dxsec_no_zeros.size(); ++i) {
+        std::cout << std::setw(10) << bins[i]
+                  << std::setw(12) << bins[i + 1]
+                  << std::setw(15) << std::scientific << std::setprecision(3) << dxsec_no_zeros[i]
+                  << std::endl;
+    }
+
     // release memory
     pineappl_grid_delete(grid);
 }

From a1a089d7e107be2ffd68a211add92d4046b31a85 Mon Sep 17 00:00:00 2001
From: peterkrack <peter.krack@yahoo.de>
Date: Mon, 17 Nov 2025 19:02:12 +0100
Subject: [PATCH 4/5] Update expected output.

---
 examples/cpp/advanced-filling.output | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/examples/cpp/advanced-filling.output b/examples/cpp/advanced-filling.output
index bfcfdfe51..173db1e88 100644
--- a/examples/cpp/advanced-filling.output
+++ b/examples/cpp/advanced-filling.output
@@ -24,3 +24,7 @@
  2.100e+00   2.200e+00      0.000e+00
  2.200e+00   2.300e+00      0.000e+00
  2.300e+00   2.400e+00      0.000e+00
+ 
+  bin left   bin right        dsig/dx
+-------------------------------------
+ 0.000e+00   1.000e-01      6.683e+03

From 7188e8adcf0356dc7f7be75586f1392043964d46 Mon Sep 17 00:00:00 2001
From: Radonirinaunimi <rrabeman@nikhef.nl>
Date: Mon, 17 Nov 2025 21:34:43 +0100
Subject: [PATCH 5/5] Fix formatting

---
 pineappl_capi/src/lib.rs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/pineappl_capi/src/lib.rs b/pineappl_capi/src/lib.rs
index 22ec18b2f..cdab06e62 100644
--- a/pineappl_capi/src/lib.rs
+++ b/pineappl_capi/src/lib.rs
@@ -873,9 +873,11 @@ pub unsafe extern "C" fn pineappl_grid_merge_bins(grid: *mut Grid, from: usize,
 ///
 /// TODO
 #[no_mangle]
-pub unsafe extern "C" fn pineappl_grid_delete_bins(grid: *mut Grid, 
-                                                   bin_indices_ptr: *const usize, 
-                                                   bin_indices_len: usize) {
+pub unsafe extern "C" fn pineappl_grid_delete_bins(
+    grid: *mut Grid,
+    bin_indices_ptr: *const usize,
+    bin_indices_len: usize,
+) {
     let grid = unsafe { &mut *grid };
     let bin_indices = unsafe { std::slice::from_raw_parts(bin_indices_ptr, bin_indices_len) };
     grid.delete_bins(bin_indices);