Combine multidimensional SparseArray objects

Like ordinary matrices and arrays in base R, SparseMatrix derivatives can be combined by rows or columns, with rbind() or cbind(), and multidimensional SparseArray derivatives can be bound along any dimension with abind().

Note that arbind() can also be used to combine the objects along their first dimension, and acbind() can be used to combine them along their second dimension.

Examples

## ---------------------------------------------------------------------
## COMBINING SparseMatrix OBJECTS
## ---------------------------------------------------------------------

m1a <- matrix(1:15, nrow=3, ncol=5,
              dimnames=list(NULL, paste0("M1y", 1:5)))
m1b <- matrix(101:135, nrow=7, ncol=5,
              dimnames=list(paste0("M2x", 1:7), paste0("M2y", 1:5)))
sm1a <- SparseArray(m1a)
sm1b <- SparseArray(m1b)

rbind(sm1a, sm1b)
#> <10 x 5 SparseMatrix> of type "integer" [nzcount=50 (100%)]:
#>      M1y1 M1y2 M1y3 M1y4 M1y5
#>         1    4    7   10   13
#>         2    5    8   11   14
#>         3    6    9   12   15
#> M2x1  101  108  115  122  129
#> M2x2  102  109  116  123  130
#> M2x3  103  110  117  124  131
#> M2x4  104  111  118  125  132
#> M2x5  105  112  119  126  133
#> M2x6  106  113  120  127  134
#> M2x7  107  114  121  128  135

## ---------------------------------------------------------------------
## COMBINING SparseArray OBJECTS WITH 3 DIMENSIONS
## ---------------------------------------------------------------------

a2a <- array(1:105, dim=c(5, 7, 3),
             dimnames=list(NULL, paste0("A1y", 1:7), NULL))
a2b <- array(1001:1105, dim=c(5, 7, 3),
             dimnames=list(paste0("A2x", 1:5), paste0("A2y", 1:7), NULL))
sa2a <- SparseArray(a2a)
sa2b <- SparseArray(a2b)

abind(sa2a, sa2b)               # same as 'abind(sa2a, sa2b, along=3)'
#> <5 x 7 x 6 SparseArray> of type "integer" [nzcount=210 (100%)]:
#> ,,1
#>      A1y1 A1y2 A1y3 A1y4 A1y5 A1y6 A1y7
#> A2x1    1    6   11   16   21   26   31
#> A2x2    2    7   12   17   22   27   32
#> A2x3    3    8   13   18   23   28   33
#> A2x4    4    9   14   19   24   29   34
#> A2x5    5   10   15   20   25   30   35
#> 
#> ...
#> 
#> ,,6
#>      A1y1 A1y2 A1y3 A1y4 A1y5 A1y6 A1y7
#> A2x1 1071 1076 1081 1086 1091 1096 1101
#> A2x2 1072 1077 1082 1087 1092 1097 1102
#> A2x3 1073 1078 1083 1088 1093 1098 1103
#> A2x4 1074 1079 1084 1089 1094 1099 1104
#> A2x5 1075 1080 1085 1090 1095 1100 1105
#> 
abind(sa2a, sa2b, rev.along=0)  # same as 'abind(sa2a, sa2b, along=4)'
#> <5 x 7 x 3 x 2 SparseArray> of type "integer" [nzcount=210 (100%)]:
#> ,,1,1
#>      A1y1 A1y2 A1y3 A1y4 A1y5 A1y6 A1y7
#> A2x1    1    6   11   16   21   26   31
#> A2x2    2    7   12   17   22   27   32
#> A2x3    3    8   13   18   23   28   33
#> A2x4    4    9   14   19   24   29   34
#> A2x5    5   10   15   20   25   30   35
#> 
#> ...
#> 
#> ,,3,2
#>      A1y1 A1y2 A1y3 A1y4 A1y5 A1y6 A1y7
#> A2x1 1071 1076 1081 1086 1091 1096 1101
#> A2x2 1072 1077 1082 1087 1092 1097 1102
#> A2x3 1073 1078 1083 1088 1093 1098 1103
#> A2x4 1074 1079 1084 1089 1094 1099 1104
#> A2x5 1075 1080 1085 1090 1095 1100 1105
#> 

a3a <- array(1:60, dim=c(3, 5, 4),
             dimnames=list(NULL, paste0("A1y", 1:5), NULL))
a3b <- array(101:240, dim=c(7, 5, 4),
             dimnames=list(paste0("A2x", 1:7), paste0("A2y", 1:5), NULL))
sa3a <- SparseArray(a3a)
sa3b <- SparseArray(a3b)

arbind(sa3a, sa3b)  # same as 'abind(sa3a, sa3b, along=1)'
#> <10 x 5 x 4 SparseArray> of type "integer" [nzcount=200 (100%)]:
#> ,,1
#>      A1y1 A1y2 A1y3 A1y4 A1y5
#>         1    4    7   10   13
#>         2    5    8   11   14
#>  ...    .    .    .    .    .
#> A2x6  106  113  120  127  134
#> A2x7  107  114  121  128  135
#> 
#> ...
#> 
#> ,,4
#>      A1y1 A1y2 A1y3 A1y4 A1y5
#>        46   49   52   55   58
#>        47   50   53   56   59
#>  ...    .    .    .    .    .
#> A2x6  211  218  225  232  239
#> A2x7  212  219  226  233  240
#> 

## ---------------------------------------------------------------------
## Sanity checks
## ---------------------------------------------------------------------

sm1 <- rbind(sm1a, sm1b)
m1 <- rbind(m1a, m1b)
stopifnot(identical(as.array(sm1), m1), identical(sm1, SparseArray(m1)))

sa2 <- abind(sa2a, sa2b)
stopifnot(identical(sa2, abind(sa2a, sa2b, along=3)))
a2 <- abind(a2a, a2b, along=3)
stopifnot(identical(as.array(sa2), a2), identical(sa2, SparseArray(a2)))

sa2 <- abind(sa2a, sa2b, rev.along=0)
stopifnot(identical(sa2, abind(sa2a, sa2b, along=4)))
a2 <- abind(a2a, a2b, along=4)
stopifnot(identical(as.array(sa2), a2), identical(sa2, SparseArray(a2)))

sa3 <- arbind(sa3a, sa3b)
a3 <- arbind(a3a, a3b)
stopifnot(identical(as.array(sa3), a3), identical(sa3, SparseArray(a3)))

See also

Examples