Migrate (~TFM_MIG)

~TFM_MIG copies existing values to new indexes: under another attribute, year, commodity, timeslice, currency, limit type, other index, stage or state of the world, optionally rescaling them on the way. It selects its sources like ~TFM_UPD: rule-based filters, applied to the seed values of the layer, with SourceScen to name the source layer.

Accepted in BY_Trans, SubRES_*_Trans, SysSettings, trade, regular, NSV and generated parametric files. The layouts ~TFM_MIG-AT and ~TFM_MIG-TS work as for the other tags (layouts).

Source and destination columns

Most index columns come in pairs. The plain column selects the source values; the column with the suffix 2 gives the destination. Where no 2 column is given, the index keeps its source value.

Source (filter)	Destination	Typical use
Attribute	Attribute2	write the same numbers under another attribute
Year	Year2	move a base-year value to another year
cset_cn (commodity)	cset_cn2 (commodity2)	move data from one commodity to another
TimeSlice	TimeSlice2	move data between timeslices
Curr	Curr2	convert a currency (with a multiplier)
LimType	LimType2	turn a lower bound into a fixed one, …
Other_Indexes	Other_Indexes2	change a commodity group or curve number
Stage, SOW	Stage2, SOW2	stochastic stages and states of the world

These columns filter the source only and have no destination form: the process filters (pset_*), cset_cd, cset_set, Region, SourceScen, and the conditions attrib_cond, val_cond. Region and process cannot be migrated: a MIG row writes in the same region and for the same process as its source.

Destination cells take literal values; a comma list writes one copy per item (Attribute2 = NCAP_BND,ACT_BND). Wildcards are not expanded, except in cset_cn2, which is resolved like a commodity filter.

The value cell

The value cell (Value, alias AllRegions, or region columns) works as in UPD: *0.5 multiplies the source value, /, +, - apply the other operations, a bare number or ~-prefixed number replaces it. Write *1 to copy the value unchanged. A row whose value cell is empty produces nothing (the sync log says "The value is not specified").

Examples

Conditional copy to a later year. Wherever STOCK exceeds 1 for processes with geothermal, solar-thermal or heat inputs, write the same value for 2100:

~TFM_MIG: attribute=STOCK
Year2	Val_Cond	Value	pset_ci
2100	>1	*1	???GEO,???STH,???HET

Rescale and move in one row. Take PASTI of the trade transport processes, scale it by 0.062, and write it for 2019:

~TFM_MIG
Attribute	pset_pn	Year2	AllRegions
PASTI	Trd[_]*	2019	*0.0620343872322709

Set default interpolation options (from a SysSettings): migrate every ACT_BND~UP to year 0 with the option 5.

~TFM_MIG
LimType	Attribute	Year2	AllRegions	pset_pn
UP	ACT_BND	0	5	*

When to use MIG

• The same numbers must appear under another attribute, year, commodity, currency or limit type.
• A layer rescales a family of existing values.
• The change reads naturally as "wherever X is given, also give Y", rather than an enumeration of Y.

For values that do not depend on existing data, use ~TFM_INS / ~TFM_DINS. Like UPD, MIG is one of the slower tags.

MIG and UPD on the same item

MIG and UPD tables of one layer run side by side, and neither sees the other's output. If both write the same item in one layer, which value survives is not defined (processing order).