Function getPauliStrAsIndexString

quest/src/core/printer.cpp:1280–1305

string getPauliStrAsIndexString(PauliStr str, int numPaulis) {

    string out = "";

    // prematurely optimise (hehe) by avoiding repeated allocations
    // induced by below string concatenation, since we can bound the
    // string length; each Pauli is 1 char, each index is max 2 digits
    // (<64) and each inter-Pauli space is 1 char, so <=4 chars per Pauli.
    int maxLen = numPaulis * 4; // <= 256 always
    out.reserve(maxLen);

    for (int i=0; i<numPaulis; i++) {
        int code = paulis_getPauliAt(str, i);

        // don't report identities
        if (code == 0)
            continue;

        // e.g. X12 
        out += global_pauliChars[code] + toStr(i) + PAULI_SPACE_CHAR;
    }

    // out includes a trailing PAULI_SPACE_CHAR which is fine,
    // since nothing else is ever post-printed on the same line
    return out;
}


string getPauliStrAsString(PauliStr str, int numPauliChars=0) {