In do_matrix in src/array.c there is a type switch containing :
case LGLSXP :
for (i = 0; i < nr; i++)
for (j = 0; j < nc; j++)
LOGICAL(ans)[i + j * NR] = NA_LOGICAL;
That seems page inefficient, iiuc. Think it should be :
case LGLSXP :
for (j = 0; j < nc; j++)
for (i = 0; i < nr; i++)
LOGICAL(ans)[i + j * NR] = NA_LOGICAL;
or more simply :
case LGLSXP :
for (i = 0; i < nc*nr; i++)
LOGICAL(ans)[i] = NA_LOGICAL;
( with some fine tuning required since NR is type R_xlen_t whilst i, nc
and nr are type int ).
Same goes for all the other types in that switch.
This came up on Stack Overflow here :
http://stackoverflow.com/questions/12220128/reason-for-faster-matrix-allocation-in-r
Matthew
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