Flexible Array Sizes

The possibility to declare arrays with unspecified dimension sizes is quite important in order to design flexible models that can adapt to different problem sizes. An unspecified dimension size is stated by using a colon (:) instead of the usual integer expression for dimension size. The unspecified dimension sizes will eventually be determined when the array variable is bound to some value.

1 Unspecified Arrays

class Unspecified Real[:, :] y; // A matrix with two unknown dimension sizes Real[:, 3] y2; // A matrix where the number of columns is known Real M[:, size(M, 1)]; // A square matrix of unknown size end Unspecified;

Let's specify the array sizes

class Specify Unspecified unspec(y = fill(1, 3, 5), y2 = fill(1, 5, 3), M = fill(1, 2, 2)); end Specify;

1.1 Simulation of Unspecified

simulate( Specify )
val(unspec.y2[5,3],0)
plot(unspec.y2[5,3])

2 More on unspecified arrays

Several arrays with unknown sizes can of course be declared in the same declaration:

class UnspecArr Real[:] v1, v2; // Vectors v1 and v2 have unknown sizes end UnspecArr;

The actual size of v1 and v2 need not be the same even though they are part of the same declaration, since the above declaration is equivalent to two separate declarations.

class UnspecArr2 Real[:] v1; Real[:] v2; end UnspecArr2;

Let's specify the array sizes

class Specify2 UnspecArr unspecarr(v1 = {3, 7, 12}, v2 = {2, 92}); end Specify2;

2.1 Simulation of Specify2

simulate( Specify2 )
val(unspecarr.v1[3],0)
plot(unspecarr.v1[3])