MM
2016-10-27 17:35:31 UTC
Hello,
Given mpi nodes 0 .... N-1, 0 being root, master node.
and trying to determine the maximum value of a function over a large
range of values of its parameters,
What are the differences between if any:
1. At node i:
evaluate f for each of the values assigned to i of the parameters space.
calculate maximum of f
send this max back to root node, and calculate max of maxes.
2. Assuming all nodes handle the same number of values of the parameters of f:
evaluate f for each....
reduce the array of f results back to root node using the MAX OP for e.g.
at root node, calculate the max of maxes
feels like doing rows then columns vs columns then rows in a matrix.
Basically, what can help me choose?
Performance is always factor 1. If same performance, then code
simplicity comes second
thanks,
Given mpi nodes 0 .... N-1, 0 being root, master node.
and trying to determine the maximum value of a function over a large
range of values of its parameters,
What are the differences between if any:
1. At node i:
evaluate f for each of the values assigned to i of the parameters space.
calculate maximum of f
send this max back to root node, and calculate max of maxes.
2. Assuming all nodes handle the same number of values of the parameters of f:
evaluate f for each....
reduce the array of f results back to root node using the MAX OP for e.g.
at root node, calculate the max of maxes
feels like doing rows then columns vs columns then rows in a matrix.
Basically, what can help me choose?
Performance is always factor 1. If same performance, then code
simplicity comes second
thanks,