There are two major additions in this commit. The first is a new storage
trait, `ReshapableStorage`, that can be implemented for storage types
that can be reshaped in-place. I have implemented this for both the
`ArrayStorage` and `VecStorage` types, as they are the most common and
they are just interpretations of a flat list.
The second is a `Matrix::reshape_generic` method that allows matrices to
be in-place reshaped provided that the underlying storage can handle it.
In practice, this means that the standard matrix types (`MatrixMN` and
`DMatrix`) can be resized to any size that has the same element count.
Resizing between array and vector storage is not implemented due to
`Storage` only being implemented for `VecStorage` variants where at
least one dimension is `Dynamic`.
Additionally, only the generic reshape function is added as it can be a
basis for other reshaping functions (see the resizing functions) and I
am not particularly in the mood to implement a variety of reshaping
methods.
Previously, most dimension mismatch asserts used raw `assert!` and did
not include the mismatching dimensions in the panic message. When using
dynamic matrices, this led to somewhat-opaque panics such as:
```rust
let m1 = DMatrix::<f32>::zeros(2, 3);
let m2 = DMatrix::<f32>::zeros(5, 10);
m1 + m2 // panic: Matrix addition/subtraction dimensions mismatch.
```
This patch adds dimension information in the panic messages wherever
doing so did not add additional bounds checks, mostly by simply changing
`assert!(a == b, ...)` cases to `assert_eq!`. After:
```rust
// panic: assertion failed: `(left == right)`
// left: `(2, 3)`,
// right: `(5, 10)`: Matrix addition/subtraction dimensions mismatch.
```
Note that the `gemv` and `ger` were not updated, as they are called from
within other functions on subset matricies -- e.g., `gemv` is called
from `gemm` which is called from `mul_to` . Including dimension
information in the `gemv` panic messages would be confusing to
`mul` / `mul_to` users, because it would include dimensions of the column
vectors that `gemm` passes to `gemv` rather than of the original `mul`
arguments. A fix would be to add bounds checks to `mul_to`, but that may
have performance and redundancy implications, so is left to another
patch.
Philippe Renon
Crozet Sébastien
Nathan Kent
Michael Morgan
Michael Stevens
Frans Skarman
danielschlaugies
CGMossa
Adam Nemecek
Andreas Longva
Jenan Wise
Chris Hodapp
Fredrik Jansson