# Implementing ZLB with deterministic simulation **URL:** \ **Category:** Dynare contributions and examples\ **Created:** [14 February 2014 17:37 UTC](https://forum.dynare.org/t/implementing-zlb-with-deterministic-simulation/3696 "2014-02-14T17:37:29Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Palumenis](https://forum.dynare.org/letter_avatar_proxy/v4/letter/p/ecae2f/32.png) [@Palumenis](https://forum.dynare.org/u/Palumenis)\ **Post date:** [14 February 2014 17:37 UTC](https://forum.dynare.org/t/implementing-zlb-with-deterministic-simulation/3696/1 "2014-02-14T17:37:29Z")
Dear all, I have a problem setting up my model with a ZLB constraint on interest rates. If I run a deterministic simulation without constraints there is an initial drop of the interest rate to -3%. When I implement it with the ZLB there is a warning: Warning: Matrix is singular to working precision. > In sim1 at 133 > In simul at 108 > In real\_only\_g\_ZLB at 248 > In dynare at 120 When I manually set the interest rate in the first period to 0 the algorithm converges and the ZLB is not binding anymore. I am wondering whether it is more likely that my ZLB-implementation is wrong or that there is only a solution if either the initial interest rate is negative or manually set to zero. I appreciate any comments! Best, Palu ---
**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\ **Post date:** [15 February 2014 11:04 UTC](https://forum.dynare.org/t/implementing-zlb-with-deterministic-simulation/3696/2 "2014-02-15T11:04:10Z")
I would need the mod-file ---
**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\ **Post date:** [19 February 2014 10:07 UTC](https://forum.dynare.org/t/implementing-zlb-with-deterministic-simulation/3696/3 "2014-02-19T10:07:24Z")
```auto on your model B says [quote]model_diagnostic: the Jacobian of the static model is singular there is 1 colinear relationships between the variables and the equations Colinear variables: c n g tau gamma1 gamma2 gamma3 gamma4 Colinear equations 5 13 The presence of a singularity problem typically indicates that there is one redundant equation entered in the model block, while another non-redundant equation is missing. The problem often derives from Walras Law.[/quote] ``` on your model B says [quote]model\_diagnostic: the Jacobian of the static model is singular there is 1 colinear relationships between the variables and the equations Colinear variables: c n g tau gamma1 gamma2 gamma3 gamma4 Colinear equations 5 13 The presence of a singularity problem typically indicates that there is one redundant equation entered in the model block, while another non-redundant equation is missing. The problem often derives from Walras Law.[/quote]