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Specify information about the dimensionality of an input port


int_T ssSetInputPortDimensionInfo(SimStruct *S,  int_T port, 
 DimsInfo_T *dimsInfo)



SimStruct that represents an S-Function block.


Index of an input port.


Structure of type DimsInfo_T that specifies the dimensionality of the signals accepted by port.

The structure is defined as

typedef struct DimsInfo_tag{ 
    int  width;			/* number of elements   */
    int  numDims		/* Number of dimensions */
    int  *dims;			/* Dimensions.          */


  • numDims specifies the number of dimensions of the signal, e.g., 1 for a 1-D (vector) signal or 2 for a 2-D (matrix) signal, or DYNAMICALLY_SIZED if the number of dimensions is determined dynamically.

  • dims is an integer array that specifies the size of each dimension, e.g., [2 3] for a 2-by-3 matrix signal, or DYNAMICALLY_SIZED for each dimension that is determined dynamically, e.g., [2 DYNAMICALLY_SIZED].

  • width equals the total number of elements in the signal, e.g., 12 for a 3-by-4 matrix signal or 8 for an 8-element vector signal, or DYNAMICALLY_SIZED if the total number of elements is determined dynamically.


    Use the macro, DECL_AND_INIT_DIMSINFO, to declare and initialize an instance of this structure.


1 if successful; otherwise, 0.


Specifies the dimension information for port. Use this function in mdlInitializeSizes to initialize the input port dimension information. If you want the port to inherit its dimensions from the port to which it is connected, specify DYNAMIC_DIMENSION as the dimsInfo for port. In this case, the S-function must provide mdlSetInputPortDimensionInfo and mdlSetDefaultPortDimensionInfo methods to enable the signal dimensions to be set correctly during signal propagation.


C, C++


The following example specifies that input port 0 accepts 2-by-2 matrix signals.

    int_T dims[2];

    di.numDims = 2;
    dims[0] = 2;
    dims[1] = 2;
    di.dims = dims;
    di.width = 4;
    ssSetInputPortDimensionInfo(S, 0, &di);

See the S-function sfun_matadd.c used in sfcndemo_matadd and the S-function sdotproduct.c used in sfcndemo_sdotproduct for complete examples that use this function.

Version History

Introduced before R2006a