# sminreal

Eliminates structurally disconnected states, delays, and blocks

## Description

Use `sminreal`

to eliminate the states of a state-space model
that do not affect the input-output response of the model.

In state-space models, `sminreal`

eliminates all states and internal
delay signals that are structurally disconnected from the inputs and outputs. The simplified
model is structurally minimal, that is, generically minimal when randomizing the nonzero
entries of state matrices.

In generalized models, `sminreal`

further eliminates all tunable or
uncertain blocks that are structurally disconnected from the inputs and outputs.

In gridded LTV and LPV models, `sminreal`

eliminates states and
internal delays that are structurally disconnected for *all* models in the
grid. The remaining states and internal delay signals are the same for all models across the
grid.

eliminates the states of the state-space model `msys`

= sminreal(`sys`

)`sys`

that do not affect
the input-output response and returns the simplified model `msys`

. All of
the states of the resulting state-space model `msys`

are also states of
`sys`

and the input/output response of `msys`

is
equivalent to that of `sys`

.

`[`

performs the state-consistent reduction for state-space arrays or gridded LTV or LPV models
with uniform state dimension. This means that the syntax removes only those states and
delays that do not contribute to the I/O map for `msys`

,`xkeep`

] = sminreal(`sys`

,"consistent")*all* models in
`sys`

. `xkeep`

is always a vector in this
case.

## Examples

## Input Arguments

## Output Arguments

## Tips

The model resulting from `sminreal(sys)`

is not necessarily minimal, and may
have a higher order than one resulting from `minreal(sys)`

. However,
`sminreal(sys)`

retains a subset of the original states of
`sys`

, while, in general, `minreal(sys)`

does
not.

## Version History

**Introduced before R2006a**