Build a prepayment model
Each term is:
a · TSR(SR) · TGAIN(GAIN) · TPOOL(POOL) · TTTM(TTM)
In this builder, each T(x) is chosen per variable as
None (=1), Indicator (=1[s·(x−θ)>0]),
Linear (=x), or Power (=xp).
Indicators can be combined across columns to “gate” a term, e.g.
SR · 1[GAIN > θ].
Model
Terms
Each term is: a · TSR(SR) · TGAIN(GAIN) · TPOOL(POOL) · TTTM(TTM)
Tip: Use Indicator ± in one or more columns to gate a term (multiply by 0/1), and then use Linear or Power in the column(s) you want to contribute. If you choose None, that variable contributes a factor of 1 and is ignored for that row.
Note: The table lets you enter powers, but not every combination is guaranteed to be valid
for all inputs (for example, fractional powers of negative values). The platform will do basic checks and may
mark a term invalid if it cannot be evaluated safely.
Draft model (not applied yet)
f(x) = …
This updates as you edit the table. Use Actions → Apply to make it the active model (status bar).
Tip: Use the row context menu to add / delete terms. If the grid is wide, scroll horizontally here.