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![](https://programming.dev/pictrs/image/170721ad-9010-470f-a4a4-ead95f51f13b.png)
I’ve been a four-star programmer a few times. Imagine a blocked symmetric matrix where the rows and columns are indexed by triples (u,v,w). The entries are zero whenever u != u’ or v != v’, and because of symmetry you only store entries with w <= w’. But the range of v depends on the value of u and the range of w on the value of v. So you do
double ****mat = calloc (UMAX, sizeof(*mat));
for (int u = 0; u < UMAX; ++u) {
mat[u] = calloc (u + 1, sizeof(**mat));
for (int v = 0; v <= u; ++v) {
mat[u][v] = calloc (v + 1, sizeof(***mat));
for (int w = 0; w <= v; ++w) {
mat[u][v][w] = calloc (w + 1, sizeof(****mat));
for (int ww = 0; ww <= w; ++ww)
mat[u][v][w][ww] = some_function (u, v, w, ww);
}
}
}
and weep a little. In reality, this gets a bit optimized by allocating a single chunk of memory and carving that up into the pointer and data arrays, so everything is reasonably close together in memory.
Beltalowda best at rock tossing! Not Olympic discipline, sasa que. Damn inyalowda.