DELAY FIXED fails with zero delay time

[ToddFincannon]

The Vensim docs don't say how a zero delay time for DELAY FIXED should be interpreted. For instance:

delay time = 0 ~~|
init value = 0 ~~|
a = DELAY FIXED(input, delay time, init value) ~~|

Experimentation shows that the output for a zero delay is the same as a delay of one time step. Instead, in SDEverywhere the output is always the init value.

[ToddFincannon]

There is an inherent one time step delay with DELAY FIXED because it is a level variable. That's why a zero delay time has the same output as for a one time step delay. The best way to interpret a zero delay is that DELAY FIXED takes the immediate value of the input. We had simply taken the initial value before.