# pwAddV

` m = pwAddV(m, *ID, *rhs)`
` m = pwAddV(m, interactive)`
Adds a reaction rate the model m. Only allowed for ODE based models.
The ID of the reaction rate can be used within the right-hand side in pwAddO.

ID The ID can be used in the right-hand side of any ODE.
Example: 'V1'
rhs Right-hand side of the rate.
Example: '- R_act*R*L'
Alternative function call for interactive specification:
interactive bool If true, the user is prompted to enter the properties
into a user interface.

## Description

When dealing with e.g. chemical networks, the differential equations
exhibit a certain structure: the flux from one node to another corresponds
to a reaction rate v which is subtracted from the derivative of the first
node and added to the derivative of the second node.
When a complete network-based formulation is not feasible for a model,
it may still prove beneficial to condense the ODEs by introducing rate
variables instead of repeating their content explicitely in the derivative
of all involved species.

## Examples

m = pwAddV(m, 'V1', 'R_act * R * L');
m = pwAddV(m, 'V2', 'R_deact * pR');
m = pwAddODE(m, 'R', '-V1 + V2');
m = pwAddODE(m, 'pR', '-V2 + V1');
instead of
m = pwAddODE(m, 'R', '-R_act * R * L + R_deact * pR');
m = pwAddODE(m, 'pR', '-R_deact * pR + R_act * R * L');

### See also