Set an element of a block's floating-point work vector
real_T ssSetRWorkValue(SimStruct *S, int_T idx, real_T value)
Sets the idx element of the S-function's floating-point work vector to value. The vector consists of elements of type real_T and is of length ssGetNumRWork(S). Typically, this vector is initialized in mdlStart or mdlInitializeConditions, updated in mdlUpdate, and used in mdlOutputs. You can use this macro in the simulation loop, mdlInitializeConditions, or mdlStart routines.
The following statement
ssSetRWorkValue(S, 0, 1.0);
sets the first element of the work vector to 1.0.