Confused about the 2d interpolation and evaluation operations in ``volepsi/volePSI/SimpleIndex.cpp``

[orzcy]

At Line 267-270 in volepsi/volePSI/SimpleIndex.cpp, there are

auto a0 = (diffBin)*sizes[numBinsLow][numBallsLow] + (1 - diffBin) * sizes[numBinsLow][numBallsHgh];
auto a1 = (diffBin)*sizes[numBinsHgh][numBallsLow] + (1 - diffBin) * sizes[numBinsHgh][numBallsHgh];

auto b0 = (diffBall)*a0 + (1 - diffBall) * a1;

I am confused why diffBin is used as the coefficient for [numBallsLow] and [numBallsHgh] to calculate a0, a1, while diffBall is used to calculate b0. It seems more natural to use diffBall when calculating a0, a1 and diffBin when calculating b0.

Therefore, should this code snippet be modified to

auto a0 = (diffBall)*sizes[numBinsLow][numBallsLow] + (1 - diffBall) * sizes[numBinsLow][numBallsHgh];
auto a1 = (diffBall)*sizes[numBinsHgh][numBallsLow] + (1 - diffBall) * sizes[numBinsHgh][numBallsHgh];

auto b0 = (diffBin)*a0 + (1 - diffBin) * a1;

Looking forward to your reply.