digitalmars.D.learn - Mir Slice.shape is not consistent with the actual array shape
- Pavel Shkadzko (41/41) May 24 2020 I am confused by the return value of Mir shape.
- Pavel Shkadzko (2/5) May 24 2020 Sorry for the typo. It should be "auto arrSlice = a.sliced;"
- jmh530 (31/33) May 24 2020 Try using fuse
- Pavel Shkadzko (6/40) May 24 2020 Yes, this works. It doesn't explain why sliced behaves like this
- Pavel Shkadzko (2/8) May 24 2020 And another typo "writeln(arr.getShape);", too rushy.
- 9il (4/7) May 24 2020 `sliced` returns a view on the array data, a 1-dimensional slice
- 9il (6/50) May 24 2020 BTW, the code example above doesn't compiles.
- Pavel Shkadzko (3/11) May 24 2020 I posted in a rush. There should be "auto arrSlice = a.sliced;"
I am confused by the return value of Mir shape. Consider the following example. /////////////////////////////////////////////////////////////////////////// import std.stdio; import std.conv; import std.array: array; import std.range: chunks; import mir.ndslice; int[] getShape(T : int)(T obj, int[] dims = null) { return dims; } // return arr shape int[] getShape(T)(T obj, int[] dims = null) { dims ~= obj.length.to!int; return getShape!(typeof(obj[0]))(obj[0], dims); } void main() { int[] arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; int[][][] a = arr.chunks(4).array.chunks(2).array; writeln(arr); writeln(arr.shape); auto arrSlice = arr.sliced; writeln(arrSlice); writeln(arrSlice.shape); } /////////////////////////////////////////////////////////////////////////// [[[1, 2, 3, 4], [5, 6, 7, 8]], [[9, 10, 11, 12], [13, 14, 15, 16]]] [2, 2, 4] <-- correct shape [[[1, 2, 3, 4], [5, 6, 7, 8]], [[9, 10, 11, 12], [13, 14, 15, 16]]] [2] <-- which shape is that? I would expect sliced to create a Slice with the same dims. Well, sliced returns a shell over the array, but why does it return its own shape instead of the shape of the array it provides view into? This makes it even more confusing once you print both representations. What's the rationale here?
May 24 2020
On Sunday, 24 May 2020 at 14:17:33 UTC, Pavel Shkadzko wrote:I am confused by the return value of Mir shape. Consider the following example. [...]Sorry for the typo. It should be "auto arrSlice = a.sliced;"
May 24 2020
On Sunday, 24 May 2020 at 14:21:26 UTC, Pavel Shkadzko wrote:[snip] Sorry for the typo. It should be "auto arrSlice = a.sliced;"Try using fuse /+dub.sdl: dependency "mir-algorithm" version="*" +/ import std.stdio; import std.conv; import std.array: array; import std.range: chunks; import mir.ndslice; int[] getShape(T : int)(T obj, int[] dims = null) { return dims; } // return arr shape int[] getShape(T)(T obj, int[] dims = null) { dims ~= obj.length.to!int; return getShape!(typeof(obj[0]))(obj[0], dims); } void main() { int[] arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; int[][][] a = arr.chunks(4).array.chunks(2).array; int err; writeln(arr); writeln(a.shape(err)); auto aSlice = a.fuse; writeln(aSlice); writeln(aSlice.shape); }
May 24 2020
On Sunday, 24 May 2020 at 14:35:33 UTC, jmh530 wrote:On Sunday, 24 May 2020 at 14:21:26 UTC, Pavel Shkadzko wrote:Yes, this works. It doesn't explain why sliced behaves like this though. Also, isn't sliced the default way of converting D arrays to Mir arrays? Above all arr.fuse.field flattens the array. So, fuse works as D join if combined with field but as slice allocator is used on a D array...[snip] Sorry for the typo. It should be "auto arrSlice = a.sliced;"Try using fuse /+dub.sdl: dependency "mir-algorithm" version="*" +/ import std.stdio; import std.conv; import std.array: array; import std.range: chunks; import mir.ndslice; int[] getShape(T : int)(T obj, int[] dims = null) { return dims; } // return arr shape int[] getShape(T)(T obj, int[] dims = null) { dims ~= obj.length.to!int; return getShape!(typeof(obj[0]))(obj[0], dims); } void main() { int[] arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; int[][][] a = arr.chunks(4).array.chunks(2).array; int err; writeln(arr); writeln(a.shape(err)); auto aSlice = a.fuse; writeln(aSlice); writeln(aSlice.shape); }
May 24 2020
On Sunday, 24 May 2020 at 14:21:26 UTC, Pavel Shkadzko wrote:On Sunday, 24 May 2020 at 14:17:33 UTC, Pavel Shkadzko wrote:And another typo "writeln(arr.getShape);", too rushy.I am confused by the return value of Mir shape. Consider the following example. [...]Sorry for the typo. It should be "auto arrSlice = a.sliced;"
May 24 2020
On Sunday, 24 May 2020 at 14:17:33 UTC, Pavel Shkadzko wrote:I am confused by the return value of Mir shape. Consider the following example. [...]`sliced` returns a view on the array data, a 1-dimensional slice composed of common D arrays. Try to use `fuse` instead of `sliced`.
May 24 2020
On Sunday, 24 May 2020 at 14:17:33 UTC, Pavel Shkadzko wrote:I am confused by the return value of Mir shape. Consider the following example. /////////////////////////////////////////////////////////////////////////// import std.stdio; import std.conv; import std.array: array; import std.range: chunks; import mir.ndslice; int[] getShape(T : int)(T obj, int[] dims = null) { return dims; } // return arr shape int[] getShape(T)(T obj, int[] dims = null) { dims ~= obj.length.to!int; return getShape!(typeof(obj[0]))(obj[0], dims); } void main() { int[] arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; int[][][] a = arr.chunks(4).array.chunks(2).array; writeln(arr); writeln(arr.shape); auto arrSlice = arr.sliced; writeln(arrSlice); writeln(arrSlice.shape); } /////////////////////////////////////////////////////////////////////////// [[[1, 2, 3, 4], [5, 6, 7, 8]], [[9, 10, 11, 12], [13, 14, 15, 16]]] [2, 2, 4] <-- correct shape [[[1, 2, 3, 4], [5, 6, 7, 8]], [[9, 10, 11, 12], [13, 14, 15, 16]]] [2] <-- which shape is that? I would expect sliced to create a Slice with the same dims. Well, sliced returns a shell over the array, but why does it return its own shape instead of the shape of the array it provides view into? This makes it even more confusing once you print both representations. What's the rationale here?BTW, the code example above doesn't compiles. OT: Instead ofint[] arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; int[][][] a = arr.chunks(4).array.chunks(2).array;you can generate the same common D array using Mir: auto a = [2, 2, 4].iota!int(1).ndarray;
May 24 2020
On Sunday, 24 May 2020 at 15:24:14 UTC, 9il wrote:On Sunday, 24 May 2020 at 14:17:33 UTC, Pavel Shkadzko wrote:I posted in a rush. There should be "auto arrSlice = a.sliced;" and "writeln(a.getShape);".[...]BTW, the code example above doesn't compiles. OT: Instead of[...]you can generate the same common D array using Mir: auto a = [2, 2, 4].iota!int(1).ndarray;
May 24 2020