[BUG] unable to pad a corner or a side

[sk4r]

Description

https://github.com/arrayfire/arrayfire/blob/c7f16cca120f722014458696e50aa292cb803e76/test/pad_borders.cpp#L147-L159 tells me I should be able to pad a corner.

arrayfire-rust uses af_pad wrapper around the function being tested in that code. That wrapper checks for nonzero number of dimensions (https://github.com/arrayfire/arrayfire/blob/1405a9448f79ca56cc875f57db36cc6c33806272/src/api/c/data.cpp#L431-L432).

The problem is if begin/end padding is &[0, 0, 0, 0], this line

arrayfire-rust/src/core/data.rs

Line 951 in 39ab7a5

begin.ndims() as c_uint,

tells af_pad that there are 0 dimensions (begin.ndims() calls begin.elements() which multiplies all 4 values and ends up being 0).

ArrayFire v3.7.2 (CPU, 64-bit Linux, build default)
[0] AMD: AMD Ryzen 7 2700X Eight-Core Processor
[3 3 1 1]
    1.0000     1.0000     1.0000
    1.0000     1.0000     1.0000
    1.0000     1.0000     1.0000

thread 'main' panicked at 'Error message: Size is incorrect
Last error: In function af_err af_pad(void**, af_array, unsigned int, const dim_t*, unsigned int, const dim_t*, af_border_type)
In file src/api/c/data.cpp:431
Invalid dimension for argument 2
Expected: begin_ndims > 0 && begin_ndims <= 4

Reproducible Code and/or Steps

    let a = constant::<f32>(1.0, Dim4::new(&[3, 3, 1, 1]));
    print(&a);
    let begin_dims = Dim4::new(&[0, 0, 0, 0]);
    let end_dims = Dim4::new(&[2, 2, 0, 0]);
    let padded = pad(&a, begin_dims, end_dims, BorderType::ZERO);
    print(&padded);

System Information

Checklist

• Using the latest available ArrayFire release
• GPU drivers are up to date

[sk4r]

Locally fixed like this but I wasn't sure if there's a better way so didn't submit a PR

diff --git a/src/core/data.rs b/src/core/data.rs
index 22dfc04..40bfe3e 100644
--- a/src/core/data.rs
+++ b/src/core/data.rs
@@ -948,9 +948,9 @@ pub fn pad<T: HasAfEnum>(
         let err_val = af_pad(
             &mut temp as *mut af_array,
             input.get(),
-            begin.ndims() as c_uint,
+            begin.get().len() as c_uint,
             begin.get().as_ptr() as *const dim_t,
-            end.ndims() as c_uint,
+            end.get().len() as c_uint,
             end.get().as_ptr() as *const dim_t,
             fill_type as c_uint,
         );

[9prady9]

@sk4r Thank you for reporting it. Simple but yet bad one it is, sorry about the inconvenience. I didn't realize that dim4::ndims method doesn't exactly represent length of this array. What you have is also correct and but since dim4 represents size upto a maximum of 4 dimensions in this case, we can just hard code it to 4.

The fix (will be pushed to #244) for this will be available in next release.

[9prady9]

I am going to merge the fix soon and you should be able to use master branch from your rust Cargo.toml directly even though the crate isn't published yet.

[sk4r]

Pulled the latest, thanks for the quick fix!