Function operator-

src/opr/impl/blas.cpp:628–632

}

SafeSymbolVar operator-(SafeSymbolVar x) {
    if (x.node())
        return -x.s();
    return {};
}

#define OP(x, a_, b_)                                            \
    SafeSymbolVar operator x(SafeSymbolVar a, SafeSymbolVar b) { \