abs2active - Convert constraints from absolute to active format

Syntax

ActiveConSet = abs2active(AbsConSet, Index)

Arguments

AbsConSet

Portfolio linear inequality constraint matrix expressed in absolute weight format. AbsConSet is formatted as [A b] such that A*w <= b, where A is a number of constraints (NCONSTRAINTS) by number of assets (NASSETS) weight coefficient matrix, and b and w are column vectors of length NASSETS. The value w represents a vector of absolute asset weights whose elements sum to the total portfolio value.

See the output ConSet from portcons for additional details about constraint matrices.

Index

NASSETS-by-1 vector of index portfolio weights. The sum of the index weights must equal the total portfolio value (for example, a standard portfolio optimization imposes a sum-to-one budget constraint).

Description

ActiveConSet = abs2active(AbsConSet, Index) transforms a constraint matrix to an equivalent matrix expressed in active weight format (relative to the index). The transformation equation is

Therefore

The initial constraint matrix consists of NCONSTRAINTS portfolio linear inequality constraints expressed in absolute weight format. The index portfolio vector contains NASSETS assets.

ActiveConSet is the transformed portfolio linear inequality constraint matrix expressed in active weight format, also of the form [A b] such that A*w <= b. The value w represents a vector of active asset weights (relative to the index portfolio) whose elements sum to zero.

See Also

active2abs, pcalims, pcgcomp, pcglims, pcpval, portcons

  


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