If your parallel program consists of many processes, then at some breakpoint too much information may be displayed in the Debug info and Watch windows. To decrease the amount of the displayed information you can set network filter. You can set independent network filters for any of the follwing windows: Debug cursors and Call stack tabs of the Debug info window, the Watch window, the Quick watch dialog and the Break info dialog. After setting network filter only the information concerning the processes specified in the network filter is displayed. In fact, when you set network filter you choose not processes but virtual processors or entire networks. And for the processes corresponding to the virtual processors chosen in the network filter information is displayed. For example if you want to see values of watched variables only for the processes corresponding to the virtual processors of the network nw you can choose this network in the network filter and apply this filter to the Watch window.
In other words, by setting a network filter you specify a condition that is applied to global ranks of virtual processors (see mpC Tutorial). This condition is called network filter condition. The windows, to which this network filter is applied, display information for only these processes that correspond to the virtual processors satisfying the network filter condition
Remember that in general any network is limited in scope to the block, in which this network is defined. Consequently, some network may be visible at one breakpoint and invisible or even non-existent at another breakpoint. So if you choose some network, say nw1, in the network filter at some breakpoint, say 1, and the next breakpoint, say 2, is out of scope of this network, then at the breakpoint 2 no information is displayed in the windows, to which this network filter is applied. But the previous statement isnít absolutely correct because in general not all processes come to the execution point corresponding to the line of code containing the breakpoint 2 (see Cursors Overview). The following statement is more correct: for these processes, current execution position of which is within the scope of nw1, information is displayed, while for the processes that have reached the point out of scope of nw1 information isnít displayed.
Another detail to discuss is that when you set a network filter you can choose virtual processors as either members of some network or just virtual processors. The pane in the Net filter dialog displays hierarchical list of currently existing networks and virtual processors. You can expand any of networks or the Processes by clicking the (+) box, which opens into a tree that may contain additional boxes. If you expand Processes the list of processes comprising the parallel program is displayed. If you choose processes from this list then the filter is valid till the end of program execution. If you choose network or subnetwork the filter is valid as long as this network or subnetwork exists.
To set network filter
Right-click in one of the windows for which network filter can be set, and choose Select filter from the context menu. The Net filter dialog appears.
Select networks and/or virtual processors. By checking the checkboxes at the bottom of the dialog you can select windows to which this filter will be applied.
To clear network filter
Right-click in one of the windows for which network filter can be set, and choose Clear filter from the context menu.