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function C = extract (arg1, arg2, arg3, arg4, arg5, arg6, arg7)
%GRB.EXTRACT extract sparse submatrix.
%
% C = GrB.extract (Cin, M, accum, A, I, J, desc)
%
% C<M> = A(I,J) or accum (C, A(I,J))
%
% A is a required parameter. All others are optional, but if M or accum
% appears, then Cin is also required. If desc.in0 is 'transpose', then
% the description below assumes A = A' is computed first before the
% extraction (A is not changed on output, however).
%
% desc: see 'help GrB.descriptorinfo' for details.
%
% I and J are cell arrays. I contains 0, 1, 2, or 3 items:
%
% 0: { } This is the built-in ':', like A(:,J), refering to
% all m rows, if A is m-by-n.
%
% 1: { I } 1D list of row indices, like A(I,J).
%
% 2: { start,fini } start and fini are scalars (either double,
% int64, or uint64). This defines I = start:fini in
% index notation.
%
% 3: { start,inc,fini } start, inc, and fini are scalars (double,
% int64, or uint64). This defines I = start:inc:fini in
% notation.
%
% The J argument is identical, except that it is a list of column
% indices of A. If only one cell array is provided, J = { } is
% implied, refering to all n columns of A, like A(I,:).
% GrB.extract does not support linear indexing of a 2D matrix,
% as in C=A(I) when A is a 2D matrix.
%
% If neither I nor J are provided on input, then this implies both
% I = { } and J = { }, or A(:,:) refering to all rows and columns
% of A.
%
% If desc.base is 'zero-based', then I and J are interpretted as
% zero-based, where the rows and columns of A range from 0 to m-1
% and n-1, respectively. If desc.base is 'one-based' (which is the
% default), then indices are intrepetted as 1-based.
%
% Cin: an optional input matrix, containing the initial content of the
% matrix C. C on output is the content of C after the assignment is
% made. If present, Cin argument has size length(I)-by-length(J).
% If accum is present then Cin is a required input.
%
% accum: an optional binary operator, defined by a string ('+.double') for
% example. This allows for C = Cin + A(I,J) to be computed. If
% not present, no accumulator is used and C=A(I,J) is computed.
% If accum is present then Cin is a required input.
%
% M: an optional mask matrix, the same size as C.
%
% Example:
%
% A = sprand (5, 4, 0.5)
% I = [2 1 5]
% J = [3 3 1 2]
% C = GrB.extract (A, {I}, {J})
% C2 = A (I,J)
% C2 - C
%
% See also GrB/subsref.
% SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2022, All Rights Reserved.
% SPDX-License-Identifier: Apache-2.0
if (isobject (arg1))
arg1 = arg1.opaque ;
end
if (nargin > 1 && isobject (arg2))
arg2 = arg2.opaque ;
end
if (nargin > 2 && isobject (arg3))
arg3 = arg3.opaque ;
end
if (nargin > 3 && isobject (arg4))
arg4 = arg4.opaque ;
end
if (nargin > 4 && isobject (arg5))
arg5 = arg5.opaque ;
end
if (nargin > 5 && isobject (arg6))
arg6 = arg6.opaque ;
end
switch (nargin)
case 1
[C, k] = gbextract (arg1) ;
case 2
[C, k] = gbextract (arg1, arg2) ;
case 3
[C, k] = gbextract (arg1, arg2, arg3) ;
case 4
[C, k] = gbextract (arg1, arg2, arg3, arg4) ;
case 5
[C, k] = gbextract (arg1, arg2, arg3, arg4, arg5) ;
case 6
[C, k] = gbextract (arg1, arg2, arg3, arg4, arg5, arg6) ;
case 7
[C, k] = gbextract (arg1, arg2, arg3, arg4, arg5, arg6, arg7) ;
end
if (k == 0)
C = GrB (C) ;
end
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