See also: #929
Currently we require all process flows to be either negative or positive, but they cannot be zero. I can imagine that there could be cases where a flow is zero for one or more years, though we may want to disallow having the coeff for a particular commodity flow being zero in every year (you could just omit it in this case).
It may be worth doing this in after #927, because once we've closed that every flow will be either an input or output for every year; at present, flows can change direction between years, which is weird and will potentially make fixing this issue harder.
See also: #929
Currently we require all process flows to be either negative or positive, but they cannot be zero. I can imagine that there could be cases where a flow is zero for one or more years, though we may want to disallow having the
coefffor a particular commodity flow being zero in every year (you could just omit it in this case).It may be worth doing this in after #927, because once we've closed that every flow will be either an input or output for every year; at present, flows can change direction between years, which is weird and will potentially make fixing this issue harder.