Every training run starts with a choice of initial weight values before a single gradient step is taken. This scene represents a simplified loss landscape as a 3D surface: low points (valleys) are good parameter settings, the deepest gold-marked valley is the global minimum, and the surrounding bumps are local minima that can trap an optimizer. Each glowing particle is one training run, placed on the surface according to the chosen initialization strategy, then descending the gradient step by step — just like gradient descent updating a model's weights.
Before Xavier Glorot & Yoshua Bengio's 2010 initialization scheme and Kaiming He's 2015 follow-up for ReLU networks, deep nets were notoriously hard to train simply because naive random initialization made gradients vanish or explode within a few layers — no amount of tuning the learning rate could fix a bad starting point.
A 3D loss landscape where glowing particles, each representing a training run, start from positions determined by a chosen weight-initialization strategy and descend the gradient toward a marked global minimum — or get stuck along the way.
Zero and oversized initial values tend to stall or overshoot, naive wide-random scatter is a gamble, while variance-scaled schemes like Xavier/Glorot and He keep runs in a band that reliably reaches the global minimum.
Pick an init strategy, set the learning rate and landscape ruggedness, then watch the particles descend. Re-initialize to resample fresh starting points and compare how many reach the gold global-minimum marker.
Kaiming He's 2015 initialization scheme for ReLU networks uses roughly double the variance of Xavier/Glorot init, compensating for the fact that ReLU zeroes out half of its inputs on average.