For a particular test case, in the benthic algae component of PLANK, the computed benthic algae density increases with each time step until it crosses the threshold set by input parameter MBAL in table BENAL-PARM, as expected. Crossing this threshold occurs one time step later in HSP2 than it did in HSPF. After closer examination, it is apparent the differences in benthic algae density are within the expected numeric precision, but the small difference is enough to affect the occurrence of overcrowding by one time step.
This issue focuses a possible shortcoming of the testing code, where comparing each value at each time step can provide misleading indications of non-matching results.
For a particular test case, in the benthic algae component of PLANK, the computed benthic algae density increases with each time step until it crosses the threshold set by input parameter MBAL in table BENAL-PARM, as expected. Crossing this threshold occurs one time step later in HSP2 than it did in HSPF. After closer examination, it is apparent the differences in benthic algae density are within the expected numeric precision, but the small difference is enough to affect the occurrence of overcrowding by one time step.
This issue focuses a possible shortcoming of the testing code, where comparing each value at each time step can provide misleading indications of non-matching results.