1function C = ne (A, B) 2%A ~= B not equal. 3% C = (A ~= B) is an element-by-element comparison of A and B. One or 4% both may be scalars. Otherwise, A and B must have the same size. 5% 6% See also GrB/lt, GrB/le, GrB/gt, GrB/ge, GrB/eq. 7 8% FUTURE: ne(A,B) for two matrices A and B is slower than it could be. 9% See comments in gb_union_op. 10 11% The pattern of C depends on the type of inputs: 12% A scalar, B scalar: C is scalar. 13% A scalar, B matrix: C is full if A~=0, otherwise C is a subset of B. 14% B scalar, A matrix: C is full if B~=0, otherwise C is a subset of A. 15% A matrix, B matrix: C is sparse, with the pattern of A+B. 16% Zeroes are then dropped from C after it is computed. 17 18% SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2021, All Rights Reserved. 19% SPDX-License-Identifier: GPL-3.0-or-later 20 21if (isobject (A)) 22 A = A.opaque ; 23end 24 25if (isobject (B)) 26 B = B.opaque ; 27end 28 29[am, an, atype] = gbsize (A) ; 30[bm, bn, btype] = gbsize (B) ; 31a_is_scalar = (am == 1) && (an == 1) ; 32b_is_scalar = (bm == 1) && (bn == 1) ; 33ctype = gboptype (atype, btype) ; 34 35if (a_is_scalar) 36 if (b_is_scalar) 37 % both A and B are scalars. C is sparse. 38 C = GrB (gb_union_op ('~=', A, B)) ; 39 else 40 % A is a scalar, B is a matrix 41 if (gb_scalar (A) ~= 0) 42 % since a ~= 0, entries not present in B result in a true 43 % value, so the result is full. Expand A to a full matrix. 44 A = gb_scalar_to_full (bm, bn, ctype, gb_fmt (B), A) ; 45 C = GrB (gbemult (A, '~=', gbfull (B, ctype))) ; 46 else 47 % since a == 0, entries not present in B result in a false 48 % value, so the result is a sparse subset of B. select all 49 % entries in B ~= 0, then convert to true. 50 C = GrB (gbnew (B, 'logical')) ; 51 end 52 end 53else 54 if (b_is_scalar) 55 % A is a matrix, B is a scalar 56 if (gb_scalar (B) ~= 0) 57 % since b ~= 0, entries not present in A result in a true 58 % value, so the result is full. Expand B to a full matrix. 59 B = gb_scalar_to_full (am, an, ctype, gb_fmt (A), B) ; 60 C = GrB (gbemult (gbfull (A, ctype), '~=', B)) ; 61 else 62 % since b == 0, entries not present in A result in a false 63 % value, so the result is a sparse subset of A. Simply 64 % typecast A to logical. Explicit zeroes in A become explicit 65 % false entries. Any other explicit entries not equal to zero 66 % become true. 67 C = GrB (gbnew (A, 'logical')) ; 68 end 69 else 70 % both A and B are matrices. C is sparse. 71 C = GrB (gb_union_op ('~=', A, B)) ; 72 end 73end 74 75