_inline_rowMix_preMultiply(row1, row2, op) {
        let [a, b, c, d] = op._2x2Breakdown();
        for (let col = 0; col < this._width; col++) {
            let x = this.cell(col, row1);
            let y = this.cell(col, row2);
            let v1 = x.times(a).plus(y.times(b));
            let v2 = x.times(c).plus(y.times(d));
            let k1 = (row1*this._width + col)*2;
            let k2 = (row2*this._width + col)*2;
            this._buffer[k1] = v1.real;
            this._buffer[k1+1] = v1.imag;
            this._buffer[k2] = v2.real;
            this._buffer[k2+1] = v2.imag;
        }
    }
@param {!int} row1
@param {!int} row2
@param {!Matrix} op
@private