Node Lateral Inflow Bug

[bemcdonnell]

@fmyers caught a small bug that is almost harmless.

In routing.c under routing_execute() there is a loop that sets the oldLatFlow to the newLatFlow for all the nodes:

    // --- initialize lateral inflows at nodes
    for (j = 0; j < Nobjects[NODE]; j++)
    {
        Node[j].oldLatFlow  = Node[j].newLatFlow;
        Node[j].newLatFlow  = 0.0;
    }

then all the lateral inflows are added to the nodes

Then it jumps down and loops through all the nodes again calling a function in nodes.c node_setOldHydState()

            for (j = 0; j < Nobjects[NODE]; j++)
            {
                node_setOldHydState(j);
                node_initInflow(j, routingStep);
            }

where node_setOldHydState() also moves OldLatFlow to NewLatFlow

void node_setOldHydState(int j)
//
//  Input:   j = node index
//  Output:  none
//  Purpose: replaces a node's old hydraulic state values with new ones.
//
{
    Node[j].oldDepth    = Node[j].newDepth;
    Node[j].oldLatFlow  = Node[j].newLatFlow; // <- Not Needed (according to Lew and Fred).
    Node[j].oldVolume   = Node[j].newVolume;
}

[dickinsonre]

@bemcdonnell I also added a link to https://www.openswmm.org/SWMM51012/routing-c in the interest of cross referencing SWMM5 issues. Is this okay?

[bemcdonnell]

@dickinsonre sure! no problem!

[fmyers]

@dickinsonre The unneeded line of code is actually in node.c, within node_setOldHydState(). I only mention it because of your link to https://www.openswmm.org/SWMM51012/routing-c and I was wondering if there is one for node-c too.

The sequence of execution ended up performing these operations, though not all in the same routine:

1. Node[j].oldLatFlow = Node[j].newLatFlow;
2. Node[j].newLatFlow = 0.0;
3. Node[j].oldLatFlow = Node[j].newLatFlow;

Line 3 ends up always forcing Node[j].oldLatFlow to 0.0 rather than leaving it with the lateral inflow from the prior routing step. Removing the line in node.c: node_setOldHydState() allows oldLatFlow to retain the prior newLatFlow value.

[dickinsonre]

Thanks, I am adding your further comments to the CHI website @fmyers