EPANET 2,2 Code runhyd in EPANET.C

 This code is a function called "runhyd" that solves the network hydraulics for a single time period in a project.

It takes in two parameters, a pointer to a "Project" struct (pr) and a pointer to a long int (t) which will hold the current time in seconds. The function returns an error code.

It first finds new demands and control actions by calling the "demands" and "controls" functions. Then it solves the network hydraulic equations by calling the "hydsolve" function and passing it the pointer to the "Project" struct, the iteration count, and the solution accuracy. If there is no error code, it then checks for system unbalance and activates the "Haltflag" if the error is too high. Finally, it reports any warning conditions by calling the "writehydwarn" function.

The function uses the following variables:

Variable	Purpose
hyd	pointer to the "Hydraul" struct in the "Project" struct
time	pointer to the "Times" struct in the "Project" struct
rpt	pointer to the "Report" struct in the "Project" struct
iter	iteration count
errcode	error code
relerr	solution accuracy

int runhyd(Project *pr, long *t) /* **-------------------------------------------------------------- ** Input: none ** Output: t = pointer to current time (in seconds) ** Returns: error code ** Purpose: solves network hydraulics in a single time period **-------------------------------------------------------------- */ { Hydraul *hyd = &pr->hydraul; Times *time = &pr->times; Report *rpt = &pr->report; int iter; // Iteration count int errcode; // Error code double relerr; // Solution accuracy // Find new demands & control actions *t = time->Htime; demands(pr); controls(pr); // Solve network hydraulic equations errcode = hydsolve(pr,&iter,&relerr); if (!errcode) { // Report new status & save results if (rpt->Statflag) writehydstat(pr,iter,relerr); // If system unbalanced and no extra trials // allowed, then activate the Haltflag if (relerr > hyd->Hacc && hyd->ExtraIter == -1) { hyd->Haltflag = 1; } // Report any warning conditions if (!errcode) errcode = writehydwarn(pr,iter,relerr); } return errcode;