Hello, I need to weight and add a certain number of rows and columns from one matrix (A) into another one (B) where I just know the corresponding row and column indices, but not the indices of the entries inside one row or one column.
For the rows, I managed to do so by calling MatGetRow() (and MatRestoreRow()) on A, getting the corresponding column indices and values to work with and add into B. For the columns, however, I just found MatGetColumnIJ() and MatGetColumnVector() in the online manual. The first seems to give access to columns and corresponding indices, but I am not sure if n corresponds to the total number of columns or just all non-zero columns. The latter (besides the warning of possibly being slow) seems to return the complete vector of values, but no indices. Is my interpretation correct so far? A bit weired workaround would be to transpose A each time a column needs to be accessed and use MatGetRow() etc. again and retranspose afterwards. Or copying the transpose of A into another matrix meaning twice the amount of data in the RAM which I would like to avoid. What would you suggest to do? Thanks and best regards Tobias -- Dipl.-Tech. Math. Tobias Neckel Institut f?r Informatik V, TU M?nchen Boltzmannstr. 3, 85748 Garching Tel.: 089/289-18602 Email: neckel at in.tum.de URL: http://www5.in.tum.de/persons/neckel.html
