traceQS

Usage: x = traceQS(A [,i1,i2])

    trace out index set i1 with i2 of given QSpace object;
    for even-rank A, missing index sets is interpreted as
    full trace of indices i1=1:r/2 with iw=r/2+1:r.
    if all indices of A are traced out, the returned x is
    a number (QSpace otherwise).

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