In the Modelica 3.3 rev 1 language specification on page 99, there is the following parameter declaration.
parameter Real A[:,:] = [1];
What does [1] mean in this context?
The operator [] is the concatenation operator. See page 15 and page 123: 10.4.2.1 Array Concatenation along First and Second Dimensions.
Basically you get as a result:
parameter Real A[1,1] = 1;
Related
I'm trying to create an unpacked array like this:
logic [3:0] AAA[0:9];
I'd like to initialize this array to the following values:
AAA = '{1, 1, 1, 1, 2, 2, 2, 3, 3, 4};
For efficiency I'd like to use repetition constructs, but that's when things are falling apart.
Is this not possible, or am I not writing this correctly? Any help is appreciated.
AAA = { '{4{1}}, '{3{2}}, '{2{3}}, 4 };
Firstly, the construct you are using is actually called the replication operator. This might help you in future searches, for example in the SystemVerilog LRM.
Secondly, you are using an array concatenation and not an array assignment in your last block of code (note the missing apostrophe '). The LRM gives the following (simple) example in Section 10.10.1 (Unpacked array concatenations compared with array assignment patterns) to explain the difference:
int A3[1:3];
A3 = {1, 2, 3}; // unpacked array concatenation
A3 = '{1, 2, 3}; // array assignment pattern
The LRM says in the same section that
...unpacked array concatenations forbid replication, defaulting, and
explicit typing, but they offer the additional flexibility of
composing an array value from an arbitrary mix of elements and arrays.
int A9[1:9];
A9 = {9{1}}; // illegal, no replication in unpacked array concatenation
Lets also have a look at the alternative: array assignment. In the same section, the LRM mentions that
...items in an assignment pattern can be replicated using syntax, such as '{ n{element} }, and can be defaulted using the default: syntax. However, every element item in an array assignment pattern must be of the same type as the element type of the target array.
If transforming it to an array assignment (by adding an apostrophe), your code actually translates to:
AAA = '{'{1,1,1,1}, '{2,2,2}, '{3,3}, 4};
This means that the SystemVerilog interpreter will only see 4 elements and it will complain that too few elements were given in the assignment.
In Section 10.9.1 (Array assignment patterns), the LRM says the following about this:
Concatenation braces are used to construct and deconstruct simple bit vectors. A similar syntax is used to support the construction and deconstruction of arrays. The expressions shall match element for element, and the braces shall match the array dimensions. Each expression item shall be evaluated in the context of an assignment to the type of the corresponding element in the array.
[...]
A syntax resembling replications (see 11.4.12.1) can be used in array assignment patterns as well. Each replication shall represent an entire single dimension.
To help interprete the bold text in the quote above, the LRM gives the following example:
int n[1:2][1:3] = '{2{'{3{y}}}}; // same as '{'{y,y,y},'{y,y,y}}
You can't do arbitrary replication of unpacked array elements.
If your code doesn't need to be synthesized, you can do
module top;
typedef logic [3:0] DAt[];
logic [3:0] AAA[0:9];
initial begin
AAA = {DAt'{4{1}}, DAt'{3{2}}, DAt'{2{3}}, 4};
$display("%p",AAA);
end
endmodule
I had another solution but I'm not sure if it is synthesizable. Would a streaming operator work here? I'm essentially taking a packed array literal and streaming it into the data structure AAA. I've put it on EDA Playground
module tb;
logic [3:0] AAA[0:9];
initial begin
AAA = { >> int {
{4{4'(1)}},
{3{4'(2)}},
{2{4'(3)}},
4'(4)
} };
$display("%p",AAA);
end
endmodule
Output:
Compiler version P-2019.06-1; Runtime version P-2019.06-1; Mar 25 11:20 2020
'{'h1, 'h1, 'h1, 'h1, 'h2, 'h2, 'h2, 'h3, 'h3, 'h4}
V C S S i m u l a t i o n R e p o r t
Time: 0 ns
CPU Time: 0.580 seconds; Data structure size: 0.0Mb
Wed Mar 25 11:20:07 2020
Done
With the following declarations:
uvec basis;
rowvec c;
sp_mat B;
The expression c(basis) seems to return an
arma::subview_elem1<double, arma::Mat<unsigned int> > and the following call appears to work:
vec pi_B = spsolve(trans(B), c(basis), "superlu");
How does spsolve resolve this input?
Also vec pi_B = spsolve(trans(B), trans(c(basis)), "superlu"); throws a dimensional mismatch error but the following runs:
rowvec d;
vec pi_B2 = spsolve(trans(B), trans(d), "superlu");
According to the documentation, c(basis) is a non-contiguous submatrix, where basis specifies which elements in c to use.
In this case c is "... interpreted as one long vector, with column-by-column ordering of the elements" and that "... the aggregate set of the specified elements is treated as a column vector", which means that c(basis) produces a column vector.
I am using openmodelica and I am trying to loop through an array in order to find the maximum value. I was able to reduce my code to a very simple test case that still gives the error. Is this something that I am doing wrong, or is this a bug in openmodelica? Here is a very simple case that does give the error:
package TestLoop
model ItemA
Real p;
end ItemA;
model ItemB
ItemA a[n];
parameter Integer n = 5;
Real p;
equation
for i in 1:n loop
a[i].p = time;
end for;
algorithm
for i in 1:n loop
p := a[i].p;
end for;
end ItemB;
end TestLoop;
The problem is in my algorithm section. Here is the error that I am getting:
TestLoop.ItemB.c:155:13: warning: implicit declaration of function '$Pa$lB' is invalid in C99 [-Wimplicit-function-declaration]
$Pp = $Pa$lB(modelica_integer)$Pi$rB$Pp;
^
TestLoop.ItemB.c:155:20: error: unexpected type name 'modelica_integer': expected expression
$Pp = $Pa$lB(modelica_integer)$Pi$rB$Pp;
^
1 warning and 1 error generated.
Any suggestions for why this might be, or how I can work around it? If I replace the assignment with a fixed value, p:=a[1].p;, the code does run (although that is not useful to me). What I ultimately want to do in the algorithm section is find the largest value of a[n].p, where I do have an equation section that does useful calculations into the array of items.
Yes, the code generation is an error of OpenModelica (it does not like unknown array indexes). Your problem is very easy to solve in a single line though (one of the following):
p = max(r for r in a.p);
p = max(a.p);
I wrote a code for concatenation as below:
module p2;
int n[1:2][1:3] = {2{{3{1}}}};
initial
begin
$display("val:%d",n[2][1]);
end
endmodule
It is showing errors.
Please explain?
Unpacked arrays require a '{} format. See IEEE Std 1800-2012 § 5.11 (or search for '{ in the LRM for many examples).
Therefore update your assignment to:
int n[1:2][1:3] = '{2{'{3{1}}}};
int n[1:2][1:3] = {2{{3{1}}}};
Just looking at {3{1}} this is a 96 bit number 3 integers concatenated together.
It is likely that {3{1'b1}} was intended.
The main issue looks to be the the left hand side is an unpacked array, and the left hand side is a packed array.
{ 2 { {3{1'b1}} } } => 6'b111_111
What is required is [[3'b111],[3'b111]],
From IEEE std 1800-2009 the array assignments section will be of interest here
10.9.1 Array assignment patterns
Concatenation braces are used to construct and deconstruct simple bit vectors.
A similar syntax is used to support the construction and deconstruction of arrays. The expressions shall match element for element, and the braces shall match the array dimensions. Each expression item shall be evaluated in the context of an
assignment to the type of the corresponding element in the array. In other words, the following examples are not required to cause size warnings:
bit unpackedbits [1:0] = '{1,1}; // no size warning required as
// bit can be set to 1
int unpackedints [1:0] = '{1'b1, 1'b1}; // no size warning required as
// int can be set to 1’b1
A syntax resembling replications (see 11.4.12.1) can be used in array assignment patterns as well. Each replication shall represent an entire single dimension.
unpackedbits = '{2 {y}} ; // same as '{y, y}
int n[1:2][1:3] = '{2{'{3{y}}}}; // same as '{'{y,y,y},'{y,y,y}}
I am following the tutorial and am trying to implement TreeBagger Method. I have a question since I cannot understand part of the code.
b = TreeBagger(nTrees,X,Y,'oobpred','on','cat',6,'minleaf',leaf(ii));
Can anyone tell me what 'cat' is and the number 6 please?
The constructor for TreeBagger:
% In addition to the optional arguments above, this method accepts all
% optional CLASSREGTREE arguments with the exception of 'minparent'.
% Refer to the documentation for CLASSREGTREE for more detail.
'cat' is not one of the valid input pairs for TreeBagger, so it must be an input for CLASSREGTREE. Looking at the input pairs for classregtree, the only input pair close to 'cat' is 'categorical,' which says:
% 'categorical' Vector of indices of the columns of X that are to be
% treated as unordered categorical variables
If you look at statgetargs.m, specifically this line:
i = strmatch(lower(pname),pnames);
It will allow any arguments as long as the first portion is spelled correctly. pnames will contain a cell array of valid strings (one of them will be 'categorical') while pname will contain a string to compare pnames with (eventually, this will contain 'cat'). If you enter only the first portion of the input string, it will still work. I.e. for me this works:
EDU>> a = TreeBagger(nTrees,X,Y,'oobpr','on','cat',6,'minle',leaf(ii));
EDU>> b = TreeBagger(nTrees,X,Y,'oobpred','on','cat',6,'minleaf',leaf(ii));
EDU>> isequal(a,b)
ans =
1
It doesn't work if 'cat' is changed because it stores 'cat' explicitly as it's spelled under TreeArgs. Regardless, 'cat' is being treated as 'categorical' for classregtree.
cat is being treated as an abbreviation of the categorical input parameter of classregtree, and it specifies that the sixth variable in X should be treated as categorical.