Adding num2cell.m (v2)

kern/private/num2cell.m

@@ -1,74 +1,87 @@
-function c = num2cell(a,dims)
-%NUM2CELL Convert numeric array into cell array.
-%   C = NUM2CELL(A) converts numeric array A into cell array C by placing
-%   each element of A into a separate cell in C. The output array has the
-%   same size and dimensions as the input array. Each cell in C contains
-%   the same numeric value as its respective element in A.
-%
-%   C = NUM2CELL(A, DIM) converts numeric array A into a cell array of
-%   numeric vectors, the dimensions of which depend on the value of the DIM
-%   argument. Return value C contains NUMEL(A)/SIZE(A,DIM) vectors, each of
-%   length SIZE(A, DIM). The DIM input must be an integer with a value from
-%   NDIMS(A) to 1.
-%
-%   C = NUM2CELL(A, [DIM1, DIM2, ...]) converts numeric array A into a cell
-%   array of numeric arrays, the dimensions of which depend on the values
-%   of arguments [DIM1, DIM2, ...]. Given the variables X and Y, where
-%   X=SIZE(A,DIM1) and Y=SIZE(A,DIM2), return value C contains
-%   NUMEL(A)/PROD(X,Y,...) arrays, each of size X-by-Y-by-.... All DIMn
-%   inputs must be an integer with a value from NDIMS(A) to 1.
-%
-%   NUM2CELL works for all array types.
-%
-%   Use CELL2MAT or CAT(DIM,C{:}) to convert back.
-%
-%   See also MAT2CELL, CELL2MAT
-
-%   Clay M. Thompson 3-15-94
-%   Copyright 1984-2022 The MathWorks, Inc.
-
-narginchk(1,2);
-if nargin==1
-    if isa(a, 'function_handle')
-        c = {a};
-        return
-    end
-    c = cell(size(a));
-    for i=1:numel(a)
-        c{i} = a(i);
-    end 
-    return
-end
-
-% Size of input array
-siz = [size(a),ones(1,max(dims)-ndims(a))];
-
-% Create remaining dimensions vector
-rdims = 1:max(ndims(a),max(dims));
-rdims(dims) = []; % Remaining dims
-
-% Size of extracted subarray
-bsize(sort(dims)) = siz(dims);
-bsize(rdims) = 1; % Set remaining dimensions to 1
-
-% Size of output cell
-csize = siz;
-csize(dims) = 1; % Set selected dimensions to 1
-c = cell(csize);
-
-% Permute A so that requested dims are the first few dimensions
-a = permute(a,[dims rdims]); 
-
-% Make offset and index into a
-offset = prod(bsize);
-ndx = 1:prod(bsize);
-try
-    for i=0:prod(csize)-1,
-        c{i+1} = reshape(a(ndx+i*offset),bsize);
-    end
-catch E
-    % This should never happen!
-    error('unexpected:num2cell', ...
-        'Unexpected error in num2cell. size(a): [%s]; dims: [%s]; offset: %d; ndx: [%s];  i: %d; error: %s', ...
-        strjoin(string(size(a))), strjoin(string(dims)), offset, strjoin(string(ndx)), i, getReport(E));
-end
+function c = num2cell(a,dims)
+%NUM2CELL Convert numeric array into cell array.
+%   C = NUM2CELL(A) converts numeric array A into cell array C by placing
+%   each element of A into a separate cell in C. The output array has the
+%   same size and dimensions as the input array. Each cell in C contains
+%   the same numeric value as its respective element in A.
+%
+%   C = NUM2CELL(A, DIM) converts numeric array A into a cell array of
+%   numeric vectors, the dimensions of which depend on the value of the DIM
+%   argument. Return value C contains NUMEL(A)/SIZE(A,DIM) vectors, each of
+%   length SIZE(A, DIM). The DIM input must be an integer with a value from
+%   NDIMS(A) to 1.
+%
+%   C = NUM2CELL(A, [DIM1, DIM2, ...]) converts numeric array A into a cell
+%   array of numeric arrays, the dimensions of which depend on the values
+%   of arguments [DIM1, DIM2, ...]. Given the variables X and Y, where
+%   X=SIZE(A,DIM1) and Y=SIZE(A,DIM2), return value C contains
+%   NUMEL(A)/PROD(X,Y,...) arrays, each of size X-by-Y-by-.... All DIMn
+%   inputs must be an integer with a value from NDIMS(A) to 1.
+%
+%   NUM2CELL works for all array types.
+%
+%   Use CELL2MAT or CAT(DIM,C{:}) to convert back.
+%
+%   See also MAT2CELL, CELL2MAT
+
+%   Clay M. Thompson 3-15-94
+%   Copyright 1984-2022 The MathWorks, Inc.
+
+narginchk(1,2);
+if nargin==1
+    if isa(a, 'function_handle')
+        c = {a};
+        return
+    end
+    c = cell(size(a));
+    for i=1:numel(a)
+        c{i} = a(i);
+    end 
+    return
+end
+
+% Size of input array
+siz = [size(a),ones(1,max(dims)-ndims(a))];
+
+% Create remaining dimensions vector
+rdims = 1:max(ndims(a),max(dims));
+rdims(dims) = []; % Remaining dims
+
+% Size of extracted subarray
+bsize(sort(dims)) = siz(dims);
+bsize(rdims) = 1; % Set remaining dimensions to 1
+
+% Size of output cell
+csize = siz;
+csize(dims) = 1; % Set selected dimensions to 1
+c = cell(csize);
+
+% Permute A so that requested dims are the first few dimensions
+a = permute(a,[dims rdims]); 
+
+% Make offset and index into a
+offset = prod(bsize);
+ndx = 1:prod(bsize);
+numelA = numel(a);
+linIndex = [];
+try
+    for i=0:prod(csize)-1,
+        linIndex = ndx+i*offset;
+        assert(all(isfinite(linIndex)), ...
+               'Elements of linear index not finite.');
+        assert(all(linIndex) > 0, ...
+               'Elements of linear index not > 0');
+        assert(all(linIndex) <= numelA, ...
+               'Elements of linear index not <= numelA');
+        assert(all(linIndex == floor(linIndex)), ...
+               'Elements of linear index not all integer-valued.');
+        aSub = a(linIndex);
+        reshaped = reshape(aSub,bsize);
+        c{i+1} = reshaped;
+    end
+catch E
+    % This should never happen!
+    error('unexpected:num2cell', ...
+        'Unexpected error in num2cell. size(a): [%s]; dims: [%s]; offset: %d; linIndex: [%s];  i: %d; error: %s', ...
+        strjoin(string(size(a))), strjoin(string(dims)), offset, strjoin(string(linIndex)), i, getReport(E));
+end