gusucode.com > bigdata 工具箱 matlab源码程序 > bigdata/+matlab/+bigdata/+internal/+util/EndMarker.m
%EndMarker Helper class for tall indexing expressions involving 'end'.
% Copyright 2015 The MathWorks, Inc.
classdef (Sealed, Hidden) EndMarker
properties (SetAccess = immutable)
% Offset can be a scalar or vector indicating the number of elements away from
% the actual end to select. Typically this value will be <= 0. Values >=
% 0 imply indexing off the end of the array.
Offset = 0
% ColonForm holds information about the beginning and end of the range, and the
% offset. If present, it is 2x3 where the first row represents absolute
% values, or NaN, and the second row represents relative values, or
% NaN. In other words,
% "2:2:end" --> [2, 2, NaN; NaN, NaN, 0]
% "end - 3:end" --> [NaN, 1, NaN; -3, NaN, 0]
% Note that the increment is always only present in the first row.
ColonForm = []
% AbsoluteValue is used when concatenating EndMarkers with numeric values.
AbsoluteValue = []
end
methods
function obj = EndMarker(offset, colonForm, absValue)
if nargin > 0
obj.Offset = offset;
end
if nargin > 1
obj.ColonForm = colonForm;
end
if nargin > 2
obj.AbsoluteValue = absValue;
end
% We must have exactly one non-empty field.
assert(sum(cellfun(@isempty, ...
{obj.Offset, obj.ColonForm, obj.AbsoluteValue})) == 2);
end
function disp(obj)
if isscalar(obj)
if ~isempty(obj.Offset)
fprintf('%s\n', iFormatEndOffset(obj.Offset));
elseif ~isempty(obj.Offset)
cf = obj.ColonForm;
Astr = iFormatOffsetOrNumber(cf(:,1));
if cf(1,2) == 1
Dstr = '';
else
Dstr = sprintf('%d:', cf(1,2));
end
Bstr = iFormatOffsetOrNumber(cf(:,3));
fprintf('%s:%s%s\n', Astr, Dstr, Bstr);
else
disp(obj.AbsoluteValue)
end
else
builtin('disp', obj);
end
end
function obj = uminus(varargin) %#ok<STOUT>
error(message('MATLAB:bigdata:array:InvalidIndexingWithEnd', 'UMINUS'));
end
function obj = times(varargin) %#ok<STOUT>
error(message('MATLAB:bigdata:array:InvalidIndexingWithEnd', 'TIMES'));
end
function obj = mtimes(varargin) %#ok<STOUT>
error(message('MATLAB:bigdata:array:InvalidIndexingWithEnd', 'MTIMES'));
end
function obj = rdivide(varargin) %#ok<STOUT>
error(message('MATLAB:bigdata:array:InvalidIndexingWithEnd', 'RDIVIDE'));
end
function obj = mrdivide(varargin) %#ok<STOUT>
error(message('MATLAB:bigdata:array:InvalidIndexingWithEnd', 'MRDIVIDE'));
end
function obj = horzcat(varargin)
obj = cat(2, varargin{:});
end
function obj = vertcat(varargin)
obj = cat(1, varargin{:});
end
function obj = cat(dim, varargin)
import matlab.bigdata.internal.util.EndMarker;
args = varargin;
for idx = 1:numel(args)
if ~iIsEndMarker(args{idx})
args{idx} = EndMarker([], [], args{idx});
end
end
obj = builtin('cat', dim, args{:});
end
function obj = plus(A, B)
import matlab.bigdata.internal.util.EndMarker;
% Ensure numeric args are 'double' - g1372212
A = iMaybeDouble(A);
B = iMaybeDouble(B);
if iIsEndMarker(A) && iIsEndMarker(B)
% No good can come of this - no way to create a valid index by adding together
% two indexing expressions that involve END. Of course, for
% ordinary MATLAB arrays, you can do this.
error(message('MATLAB:bigdata:array:InvalidEndPlusEnd'));
else
if iIsEndMarker(A)
obj = A;
incr = B;
else
obj = B;
incr = A;
end
if ~isscalar(incr)
error(message('MATLAB:bigdata:array:InvalidEndPlusNonScalar'));
end
% Update Offset/ColonForm/AbsoluteValue as appropriate
for idx = 1:numel(obj)
offset = obj(idx).Offset;
colonForm = obj(idx).ColonForm;
absValue = obj(idx).AbsoluteValue;
if ~isempty(offset)
offset = offset + incr;
end
if ~isempty(colonForm)
colonForm(:,[1,3]) = colonForm(:,[1,3]) + incr;
end
if ~isempty(absValue)
absValue = absValue + incr;
end
obj(idx) = EndMarker(offset, colonForm, absValue);
end
end
end
function obj = minus(A, B)
% Ensure numeric args are 'double' - g1372212
A = iMaybeDouble(A);
B = iMaybeDouble(B);
obj = plus(A, uminus(B));
end
function obj = colon(A, D, B)
if nargin == 2
B = D;
D = 1;
end
if islogical(D)
% Mimic the warning issued by MATLAB
warning(message('MATLAB:colon:logicalInput'));
D = double(D);
else
D = iMaybeDouble(D);
end
A = iMaybeDouble(A);
B = iMaybeDouble(B);
if ~isnumeric(D)
error(message('MATLAB:bigdata:array:EndNumericIncrement'));
end
% Resolve args - this might throw
rangeStart = iResolveColonEndpoint(A);
% Note that we do simpy extract the first value from D in the case where the
% user specified a non-scalar D.
rangeIncr = [D(1); NaN];
rangeEnd = iResolveColonEndpoint(B);
range = [rangeStart, rangeIncr, rangeEnd];
obj = matlab.bigdata.internal.util.EndMarker([], range);
end
function tf = isEquivalentToLiteralColon(objs)
%TRUE if objs is scalar, and represents '1:end'.
tf = false;
if isscalar(objs)
oneColonEndForm = [1, 1, NaN;
NaN, NaN, 0];
tf = isequaln(objs.ColonForm, oneColonEndForm);
end
end
function [tf, n, reverse] = isValidTallEndExpression(objs)
% Must represent end-k:end, or end:-1:end-k.
n = 0;
reverse = false;
% First off, check that we don't have any absolute values - they cannot be valid
% in combination with END.
for idx = 1:numel(objs)
if ~isempty(objs(idx).AbsoluteValue)
tf = false;
return
elseif ~isempty(objs(idx).ColonForm)
cf = objs(idx).ColonForm;
if ~all(isnan(cf(1,[1,3])))
tf = false;
return
end
end
end
% Use 'resolve' to compute *relative* offsets from the END by feeding it a size
% of zero.
szVec = [0 0];
dim = 1;
relIdxVec = resolve(objs, szVec, dim);
relIdxVec = relIdxVec(:);
% Now check that it's unit offset ending/beginning at the END.
if isempty(relIdxVec)
tf = true;
reverse = false;
n = 0;
else
d = diff(relIdxVec);
tf = (all(d == 1) || all(d == -1)) && max(relIdxVec) == 0;
reverse = all(d == -1);
n = numel(relIdxVec);
end
end
function [n, reverse] = getTrailingNumRows(obj)
[tf, n, reverse] = isValidTallEndExpression(obj);
assert(tf);
end
function absIdxVec = resolve(objs, sz, dim)
%RESOLVE resolve an EndMarker into an index vector for the provided chunkSize.
resultCell = cell(size(objs));
for idx = 1:numel(objs)
obj = objs(idx);
szInDim = sz(dim);
if ~isempty(obj.ColonForm)
cf = obj.ColonForm;
if ~isnan(cf(1,1))
A = cf(1,1);
else
A = szInDim + cf(2,1);
end
D = cf(1,2);
if ~isnan(cf(1,3))
B = cf(1,3);
else
B = szInDim + cf(2,3);
end
absIdxVec = A:D:B;
elseif ~isempty(obj.Offset)
% Simple offset
absIdxVec = szInDim + obj.Offset;
else
absIdxVec = obj.AbsoluteValue;
end
resultCell{idx} = absIdxVec;
end
try
absIdxVec = cell2mat(resultCell);
catch E
% Get here if the sizes didn't conform
error(message('MATLAB:bigdata:array:SizeMismatchIndexingWithEnd'));
end
end
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Resolve all numeric and logical inputs to double.
function x = iMaybeDouble(x)
if isnumeric(x) || islogical(x)
x = double(x);
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Resolve end-point values for colon operations. Reject all cases where the
% end-point is non-scalar (this is different to MATLAB which uses the first
% value - but we cannot be sure we know the first value in all cases).
%
% The return value is a 2-element column vector of [absoluteValue;
% relativeValue]. One element is NaN, the other is non-NaN.
function x = iResolveColonEndpoint(obj)
absValue = NaN;
relValue = NaN;
if ~isscalar(obj)
error(message('MATLAB:bigdata:array:EndScalarColonEndpoints'));
end
if iIsEndMarker(obj)
if ~isempty(obj.Offset)
relValue = obj.Offset;
elseif ~isempty(obj.AbsoluteValue)
absValue = obj.AbsoluteValue;
else
error(message('MATLAB:bigdata:array:EndScalarColonEndpoints'));
end
else
absValue = obj;
end
if ~isscalar(absValue) || ~isscalar(relValue)
error(message('MATLAB:bigdata:array:EndScalarColonEndpoints'));
else
x = [absValue; relValue];
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function tf = iIsEndMarker(x)
tf = isa(x, 'matlab.bigdata.internal.util.EndMarker');
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function s = iFormatEndOffset(offset)
if isscalar(offset)
if offset > 0
s = sprintf('end+%d', offset);
elseif offset < 0
s = sprintf('end%d', offset);
else
s = 'end';
end
else
strs = arrayfun(@iFormatEndOffset, offset, ...
'UniformOutput', false);
s = ['[', strjoin(strs, ','), ']'];
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function s = iFormatOffsetOrNumber(col)
if ~isnan(col(1))
s = sprintf('%d', col(1));
else
s = iFormatEndOffset(col(2));
end
end