The global reduction functions execute various global reductions on their input. Each global reduction function corresponds to a Fortran 90 intrinsic function with the same name, minus the ``Global_'' prefix. These functions require global all-to-all communication and are relatively computationally expensive. If the code is run in serial mode, then the global reduction functions are equivalent to the serial intrinsic functions.
|Output = Global_ALL (Input)||,|
|Output = Global_ANY (Input)||,|
|Output = Global_MaxVal (Input)||,|
|Output = Global_MinVal (Input)||,|
|Output = Global_Sum (Input)||or|
|Output = Global_Dot_Product (Input1, Input2)|
|Input||A real or integer (in the case of Sum, MinVal and MaxVal) or a logical (in the case of ALL and ANY) scalar, vector or 2-D array that is defined on each processor and which is to be reduced over all of the processors.|
|Input1, Input2||The two real, integer or logical vectors that are defined on each processor and that are to be reduced via a dot product over all of the processors.|
|Output||The result of the global reduction.|
The Global Reduction code listing contains additional documentation.
Michael L. Hall