Cross-posting from the github issue
(https://github.com/libmir/mir-random/issues/77) with a
workaround (execute it at https://run.dlang.io/is/Swr1xU):
----
I am not sure what the correct interface should be for this in
the long run, but for now you can use a wrapper function to
convert an ndvariable to a variable:
```d
/++
Converts an N-dimensional variable to a fixed-dimensional
variable.
+/
auto specifyDimension(ReturnType, NDVariable)(NDVariable vr)
if (__traits(isStaticArray, ReturnType) && __traits(compiles,
{static assert(NDVariable.isRandomVariable);}))
{
import mir.random : isSaturatedRandomEngine;
import mir.random.variable : isRandomVariable;
static struct V
{
enum bool isRandomVariable = true;
NDVariable vr;
ReturnType opCall(G)(scope ref G gen) if
(isSaturatedRandomEngine!G)
{
ReturnType ret;
vr(gen, ret[]);
return ret;
}
ReturnType opCall(G)(scope G* gen) if
(isSaturatedRandomEngine!G)
{
return opCall!(G)(*gen);
}
}
static assert(isRandomVariable!V);
V v = { vr };
return v;
}
```
So `main` from your above example becomes:
```d
void main()
{
import std.stdio;
import mir.random : Random, threadLocalPtr;
import mir.random.ndvariable : multivariateNormalVar;
import mir.random.algorithm : range;
import mir.ndslice.slice : sliced;
import std.range : take;
auto mu = [10.0, 0.0].sliced;
auto sigma = [2.0, -1.5, -1.5, 2.0].sliced(2,2);
Random* rng = threadLocalPtr!Random;
auto sample = rng
.range(multivariateNormalVar(mu,
sigma).specifyDimension!(double[2]))
.take(10);
writeln(sample);
}
```
