3.5 Data Reduction

void SMP_Reduce(void *data_in, void *data_out, int nitems,
                int dtype, int opr, int node);

SUBROUTINE SMP_REDUCE(DATA_IN, DATA_OUT, NITEMS, DTYPE, OPR, NODE)
<type>  DATA_IN(*), DATA_OUT(*)
INTEGER NITEMS, DTYPE, OPR, NODE

• performs data reduction among processes.

  data_in 	- points to the input data set
  data_out 	- points to the output data set
  nitems 		- number of items in the data set
  dtype 		- data type for input/output data sets
  opr 		- reduction operator
  node 		- node to which data are reduced (-1 for all nodes)
  

  <type> should match with the size specified by dtype.
  Data type (dtype) is one of (Fortran or C):

  SMP_DT_INT1 	- integer*1 	or char
  SMP_DT_INT2 	- integer*2 	or short
  SMP_DT_INT4 	- integer*4 	or int
  SMP_DT_INT8 	- integer*8 	or long (or long long)
  SMP_DT_REAL4 	- real*4 	or float
  SMP_DT_REAL8 	- real*8 	or double
  SMP_DT_CMPLX8 	- complex*8 	or struct{float r, i;}
  SMP_DT_CMPLX16 	- complex*16 	or struct{double r, i;}
  

  Reduction operator (opr) is one of (with the supported data types):

  SMP_OPR_SUM  	- sum 		(all)
  SMP_OPR_PROD 	- product 	(all)
  SMP_OPR_MIN  	- minimum 	(INT*, REAL*)
  SMP_OPR_MAX  	- maximum 	(INT*, REAL*)
  SMP_OPR_LAND 	- logical and 	(INT*)
  SMP_OPR_BAND 	- bitwise and 	(INT*)
  SMP_OPR_LOR  	- logical or 	(INT*)
  SMP_OPR_BOR  	- bitwise or 	(INT*)
  SMP_OPR_LXOR 	- logical xor 	(INT*)
  SMP_OPR_BXOR 	- bitwise xor 	(INT*)
  

• error code: SMP_ERR_DTYPE, SMP_ERR_RDOPR, SMP_ERR_MIXED