Out of Memory error In RDII.C if all R's are zero.

[dickinsonre]

This is an engine error in SWMM 5.1.013 and earlier if the user has all zero R values for the RDII UH hydrolographs. The lack of ANY zero R should be an error message and trapped in the engine.

[LRossman]

I could not reproduce this behavior for the following file (it ran successfully):

[TITLE]
;;Project Title/Notes

[OPTIONS]
;;Option                Value
FLOW_UNITS              CFS
INFILTRATION            HORTON
FLOW_ROUTING            STEADY
LINK_OFFSETS            DEPTH
MIN_SLOPE               0
ALLOW_PONDING           NO
SKIP_STEADY_STATE       NO

START_DATE              06/07/2019
START_TIME              00:00:00
REPORT_START_DATE       06/07/2019
REPORT_START_TIME       00:00:00
END_DATE                06/07/2019
END_TIME                06:00:00
SWEEP_START             01/01
SWEEP_END               12/31
DRY_DAYS                0
REPORT_STEP             00:15:00
WET_STEP                00:05:00
DRY_STEP                01:00:00
ROUTING_STEP            0:00:30 
RULE_STEP               00:00:00

INERTIAL_DAMPING        PARTIAL
NORMAL_FLOW_LIMITED     BOTH
FORCE_MAIN_EQUATION     H-W
VARIABLE_STEP           0.75
LENGTHENING_STEP        0
MIN_SURFAREA            12.566
MAX_TRIALS              8
HEAD_TOLERANCE          0.005
SYS_FLOW_TOL            5
LAT_FLOW_TOL            5
MINIMUM_STEP            0.5
THREADS                 1

[EVAPORATION]
;;Data Source       Parameters
;;--------------    ----------------
CONSTANT            0.0
DRY_ONLY            NO

[RAINGAGES]
;;Name              Format      Interval    SCF         Source    
;;--------------    ---------   ------  ------  ----------
1                   INTENSITY   1:00        1.0         TIMESERIES  1               

[JUNCTIONS]
;;Name              Elevation   MaxDepth    InitDepth   SurDepth    Aponded   
;;--------------    ----------  ----------  ----------  ----------  ----------
1                   0           0           0           0           0         

[OUTFALLS]
;;Name              Elevation   Type        Stage Data          Gated       Route To        
;;--------------    ----------  ----------  ----------------    --------    ----------------
2                   0           FREE                            NO                          

[CONDUITS]
;;Name              From Node           To Node             Length      Roughness   InOffset    OutOffset   InitFlow    MaxFlow   
;;--------------    ----------------    ----------------    ----------  ----------  ----------  ----------  ----------  ----------
1                   1                   2                   400         0.01        0           0           0           0         

[XSECTIONS]
;;Link              Shape           Geom1               Geom2       Geom3       Geom4       Barrels     Culvert   
;;--------------    ------------    ----------------    ----------  ----------  ----------  ----------  ----------
1                   CIRCULAR        1                   0           0           0           1                     

[HYDROGRAPHS]
;;Hydrograph        Rain Gage/Month     Response    R           T           K           Dmax        Drecov      Dinit   
;;--------------    ----------------    --------    --------    --------    --------    --------    --------    --------
UH1                 1               
UH1                 All                 Short       0           2           1           0           0           0       
UH1                 All                 Medium      0           6           2           0           0           0       
UH1                 All                 Long        0           12          3           0           0           0       

[RDII]
;;Node              Unit Hydrograph     Sewer Area
;;--------------    ----------------    ----------
1                   UH1                 5         

[TIMESERIES]
;;Name              Date        Time        Value     
;;--------------    ----------  ----------  ----------
1                               0           1         
1                               2           1         
1                               3           1         
1                               4           0         

[REPORT]
;;Reporting Options
SUBCATCHMENTS   ALL
NODES   ALL
LINKS   ALL

[TAGS]

[MAP]
DIMENSIONS  0.000   0.000   10000.000   10000.000
Units       None

[COORDINATES]
;;Node              X-Coord             Y-Coord           
;;--------------    ------------------  ------------------
1                   2356.495            7416.918          
2                   3776.435            6435.045          

[VERTICES]
;;Link              X-Coord             Y-Coord           
;;--------------    ------------------  ------------------

[SYMBOLS]
;;Gage              X-Coord             Y-Coord           
;;--------------    ------------------  ------------------
1                   830.816             8368.580          

[dickinsonre]

@LRossman your example works for me as well. I will post again the models that do not work for me here.

[dickinsonre]

It was probably a stupid mistake on my part. I just made five models with the same R of zero and they all work. My apologies for making a spurious issue.

[dickinsonre]

Hello, @LRossman Here is my test model that has the memory allocation issue. It is more complex than your example and does run with the RDII process flag turned off

sewer_rdii_problem.inp.txt

ERROR 101: memory allocation error.

[LRossman]

I put some debug statements into the code and ran the sewer_rdii_problem dataset. The issue seems to be an actual case of insufficient memory available to setup the RDII system for the 613 UHs in the example and has nothing to do with the R-factors being all zero. The memory issue is likely caused by the base duration of each long-term UH being 10,000 hrs (416 days), which is more than a year's response to a 1-minute rainfall (the wet time step). Each long-term UH requires an array of about 4.8 Mbytes to store previous responses for convolution purposes and there are 613 of these needed (my run crapped out at UH 348).

Thus I've concluded that this example is not evidence of a bug. It does however, suggest a couple of new features to add that might be useful. One obvious one is to have the program indicate which sub-system (in this case it's RDII) is causing an out of memory error. Another, specific to RDII, is to not allocate memory to the auxilary arrays used by a UH if its R-factor is 0.

[dickinsonre]

Thanks, @LRossman I am trying to have extreme yet comprehensive examples of all of the very nice SWMM5 features. You are always great a debugging.

[bemcdonnell]

@dickinsonre and @lrossman, realizing this would potentially alter results, have you tried compiling with 64bit compiler? This would for sure solve this particular issue since the addressable memory space would be significantly greater. It seems like the appropriate direction to take SWMM. I believe we have a 64bit build process for windows at OWA SWMM. I feel strongly that we should move to 64bit builds/distribution. I think with all the new unit tests and reg tests online, porting could be a straightforward process. Do you all have any thoughts?

[LRossman]

@bemcdonnell I just re-compiled the command line version of SWMM for 64-bits and the RDII example ran successfully. I agree that 64-bit is the future, but right now I simply want to fix the bugs listed in the Issues while keeping the engine compatible with the 32-bit Delphi GUI so that an updated version can be deployed ASAP.