Function with two-dimensional array as output

General
1

I am trying to figure out why my function isn’t working since I changed it from a 1-dimensional to 2-dimensional array output.

A very simple version of my function is below. Are there any obvious syntax errors?

functions {
    vector[] out_func(int A, int B, real num1, real num2, vector vec1, vector vec2) {     
        vector[A] out[B, B];
        out = { { vec1, num1*vec1 }, { num2*vec2, vec2 } }
        return out; 
   }
}

data {
    int A;
    int B;
    vector[A] vec1;
    vector[A] vec2;
}

parameters {
    real num1;
    real num2;
}

transformed parameters {
    vector[A] out[B, B] = out_func(A, B, num1, num2, vec1, vec2) ;
    vector[A] lam[B];
    for (b in 1:B)
        lam[b] = { out[b, 1] + out[b, 2] }
}

I get the “syntax error” output when I run it with the ^ under the r of return.

Thank you :)

2

I did also try

vector[,] out_func()

but still got the same syntax error.

3

Not sure about this, but vector is 1dim object and you return array. So try with that?

1 Like
4

There are a couple of things that are causing errors here.

First, the return type needs to be a two-dimensional array of vectors:

vector[] out_func(int A, int B, real num1, real num2, vector vec1, vector vec2)

Next, you’re missing semicolons at the end of two lines:

out = { { vec1, num1*vec1 }, { num2*vec2, vec2 } }
...
lam[b] = { out[b, 1] + out[b, 2] }

And finally, you don’t need the array initialiser ({}) around the assignment to lam, since the b-th entry is a vector:

    vector[A] lam[B];
    for (b in 1:B)
        lam[b] =  out[b, 1] + out[b, 2]

Fixing all of those, your model looks like:

functions {
    vector[,] out_func(int A, int B, real num1, real num2, vector vec1, vector vec2) {     
        vector[A] out[B, B];
        out = { { vec1, num1*vec1 }, { num2*vec2, vec2 } };
        return out; 
   }
}

data {
    int A;
    int B;
    vector[A] vec1;
    vector[A] vec2;
}

parameters {
    real num1;
    real num2;
}

transformed parameters {
    vector[A] out[B, B] = out_func(A, B, num1, num2, vec1, vec2) ;
    vector[A] lam[B];
    for (b in 1:B)
        lam[b] = out[b, 1] + out[b, 2];
}

Which compiles for me locally

2 Likes
5

Thank you. Was 100% the missing ; before the return.

Much appreciated.

2 Likes