controlledWireProbabilityJustAfter(wireIndex, colIndex) {
        return this.qubitDensityMatrix(colIndex, wireIndex).rawBuffer()[6];
    }
Returns the probability that a wire would be on if it was measured just before a given column, but conditioned on
wires with controls in that column matching their controls.
A wire is never conditioned on itself; self-conditions are ignored when computing the probability.

@param {int} wireIndex
@param {int|Infinity} colIndex
@returns {!number}