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Matrices

M2Assistant makes working with EMME/2 matrices even easier. To begin working with a matrix, click the Matrices button (or choose the View|Matrices menu option) and then select one of the initialized matrices or an ensemble. The selected matrix or ensemble is shown in the matrix table. Note the various icons beside each matrix or ensemble in the list. The icon beside a matrix indicates whether you are permitted to edit the contents of the matrix. A locked padlock indicates that the matrix cannot be edited. For ensembles, a green icon means that a zone group has been defined for the ensemble.



A scalar matrix, identified by ms, contains only one element or value. It is often used to store constants or maintain the sum of another matrix. An origin matrix has one cell or element for each origin and is identified by mo. A destination matrix has one cell or element for each destination and is identified by md. A full matrix has one cell or element for each origin-destination pair. Full matrices are identified by mf.

Right-click any matrix in the list of matrices on the left to display a popup menu with the following options:
  • Save Calculations : If the results of a matrix calculation are displayed in the matrix table, you have the option of saving these results to the selected matrix. Following confirmation, the results will be saved overwriting the previous contents of the matrix.
  • Edit Name or Initialize Matrix : This dialog is displayed when you select either menu option from the matrix popup menu. If you are initializing a matrix, you must first select the matrix to be initialized, then enter the matrix name and description and an initial value for the new matrix. Click OK to create the new matrix. If you opened this menu by selecting and then right-clicking an existing matrix, you also have the option of copying the contents of the selected matrix to the new matrix. If you are editing the name of the matrix, then only the name and description fields are available. Change the name and/or description and then click OK to save any changes.
     

  • Delete Matrix : If you are permitted to delete the selected matrix then, following confirmation, the matrix is deleted from the EMME/2 database.
  • Save Matrix : You may save a full matrix to an external file and then restore it at a later date. This is useful if you are running out of available full matrices and would like to save the results of an assignment or matrix calculation. An external matrix file has the file extension .M2X. Only full matrices can be saved or restored and only the matrix values are stored, not the matrix name nor matrix description. The difference between batching out a matrix using EMME/2 and using the M2Assistant .M2X files is that the M2Assistant stores the matrix values in compressed binary format, not text format. As a result, the size of the external matrix file is much smaller.
  • Restore Matrix : You may restore a full matrix from a previously saved external matrix. This is useful if you would like to recall the results of an assignment or matrix calculation.
  • Export Matrix : Exports the contents of the selected matrix to a comma-delimited text file.
  • Read Only : Sets or clears the write-protection status of the selected matrix.