Let $\xi = \{x^j\}_{j=1}^n$ be a grid of $n$ points in the $d$-cube
${\II}^d:=[0,1]^d$, and $\Phi = \{\phi_j\}_{j =1}^n$ a family of $n$ functions
on ${\II}^d$. We define the linear sampling algorithm $L_n(\Phi,\xi,\cdot)$ for
an approximate recovery of a continuous function $f$ on ${\II}^d$ from the
sampled values $f(x^1), ..., f(x^n)$, by $$L_n(\Phi,\xi,f)\ := \ \sum_{j=1}^n
f(x^j)\phi_j$$.