Weekday and weekend hourly time patterns for Dry Weather inflows are now correctly applied in a mutually exclusive manner in #SWMM 5.1

This is a code note about change 52 in the newer EPA SWMM 5.1.x C code

52. Weekday and weekend hourly time patterns for Dry Weather inflows are now correctly applied in a mutually exclusive manner.

 Here is the code from SWMM 5.0.022

double inflow_getDwfInflow(TDwfInflow* inflow, int month, int day, int hour)

//

//  Input:   inflow = dry weather inflow data structure

//           month = current month of year of simulation

//           day = current day of week of simulation

//           hour = current hour of day of simulation

//  Output:  returns value of dry weather inflow parameter

//  Purpose: computes dry weather inflow value at a specific point in time.

//

{

    int    i,                          // pattern type index

           p;                          // pattern index

    double f = 1.0;                    // pattern factor

    for (i=0; i<4 i="" o:p="">

    {

        p = inflow->patterns[i];

        if ( p >= 0 ) f *= inflow_getPatternFactor(p, month, day, hour);       //(5.0.019 - LR)

    }

    return f * inflow->avgValue;   

Here is the new 2014+ code,  which adjusts the pattern  factor based on the day of the week.

double inflow_getDwfInflow(TDwfInflow* inflow, int month, int day, int hour)

//

//  Input:   inflow = dry weather inflow data structure

//           month = current month of year of simulation

//           day = current day of week of simulation

//           hour = current hour of day of simulation

//  Output:  returns value of dry weather inflow parameter

//  Purpose: computes dry weather inflow value at a specific point in time.

//

{

    int    p1, p2;                     // pattern index

    double f = 1.0;                    // pattern factor

    p1 = inflow->patterns[MONTHLY_PATTERN];

    if ( p1 >= 0 ) f *= inflow_getPatternFactor(p1, month, day, hour);   // Pattern f value is 1 * The Monthly Factor

    p1 = inflow->patterns[DAILY_PATTERN];

    if ( p1 >= 0 ) f *= inflow_getPatternFactor(p1, month, day, hour);   // Pattern f value is last f * The Daily Factor

    p1 = inflow->patterns[HOURLY_PATTERN];

    p2 = inflow->patterns[WEEKEND_PATTERN];

    if ( p2 >= 0 )

    {

        if ( day == 0 || day == 6 )

            f *= inflow_getPatternFactor(p2, month, day, hour); // Pattern f value is last f * The Hourly Factor for Saturday and Sunday

        else if ( p1 >= 0 )

            f *= inflow_getPatternFactor(p1, month, day, hour); // Pattern f value is last f * The Hourly Factor Monday to Friday

    }

    else if ( p1 >= 0 ) f *= inflow_getPatternFactor(p1, month, day, hour);  // Pattern f value is last f * The Hourly Factor

    return f * inflow->avgValue;