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initval

initval;
 Command
INITIALIZATION_STATEMENT;
[INITIALIZATION_STATEMENT]
...
end;

INITIALIZATION_STATEMENT : VARIABLE_NAME = EXPRESSION;

EXPRESSION is any valid expression returning a numerical value and can contain already initialized variable names.

The required initval; ... end; block serves two purposes. It set the initial and, possibly, terminal conditions for the simulation and provides numerical initialization for various computation tasks (steady, simul, stoch_simul).

Theoreticaly, initial conditions are only necessary for lagged variables. However, as initval provides also numerical initialization, it is necessary to provide values for all variables in the model, except if the model is declared as linear.

For stochastic models, it isn't necessary to delcare 0 as initial values for exogneous stochastic variables as it is the only possible value.

When the initval block is followed by the command steady, it is not necessary to provide exact initialization values for the endogenous variables. steady will use the values provided in the initval block as initial guess in the non-linear equation solver and computes exact values for the endogenous variables at the steady state. The steady state is defined by keeping constant the value of the exogenous variables.

Example 

initval;
c = 1.2;
k = 12;
x = 1;
end;

steady;