select on multi-dimensional arrays not supported

The current implementation doesn't support select on sparse non-2D-matrices. This limits the usability of 3 and higher dimensional matrices significantly.

The following test code illustrates the problem:

    public void test3DSelect() {
        long n = 1000;
        // init sparse 3D matrix
        SparseMatrix tensor = Matrix.Factory.sparse(ValueType.BOOLEAN, n, n, n);
        tensor.setAsBoolean(true, 1L, 3L, 5L);
        tensor.setAsBoolean(true, 30L, 3L, 5L);
        tensor.setAsBoolean(true, 700L, 3L, 5L);

        // define selections to execute
        String[] selectStrings = new String[]{"*;3;5", "1;*;5", "1;3;*"};

        // select
        for (String selectString : selectStrings) {
            System.out.println("selection: " + selectString);

            // select a 1D vector
            Matrix select = tensor.select(Ret.LINK, selectString); // Exception is thrown here
            Iterable<long[]> result = select.nonZeroCoordinates();
            // take only non-zero values
            Iterator<long[]> resultIt = result.iterator();
            // print result
            while(resultIt.hasNext()){
                long[] entry = resultIt.next();
                for (int i = 0; i < entry.length; i++) {
                    System.out.print(entry[i] + " ");
                }
                System.out.print("\n");
            }
        }
    }

This code throws a RuntimeException("only supported for 2d matrices") at org.ujmp.core.objectmatrix.calculation.Selection.createAnnotation():82. The whole method createAnnotation() is widely commented out. If I comment line 82 out that throws the exception the both programs runs but returns false results.

With select on sparse 3D+ matrices ujmp would be awesome. :)

ujmp / universal-java-matrix-package

select on multi-dimensional arrays not supported #15