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.
Related
I'm trying to implement the 'Sport Scheduling Problem' (with a Round-Robin approach to break symmetries). The actual problem is of no importance. I simply want to declare the value at x[1,1] to be the set {1,2} and base the sets in the same column upon the first set. This is modelled as in the code below. The output is included in a screenshot below it. The problem is that the first set is not printed as a set but rather some sort of range while the values at x[2,1] and x[3,1] are indeed printed as sets and x[4,1] again as a range. Why is this? I assume that in the declaration of x that set of 1..n is treated as an integer but if it is not, how to declare it as integers?
EDIT: ONLY the first column of the output is of importance.
int: n = 8;
int: nw = n-1;
int: np = n div 2;
array[1..np, 1..nw] of var set of 1..n: x;
% BEGIN FIX FIRST WEEK $
constraint(
x[1,1] = {1, 2}
);
constraint(
forall(t in 2..np) (x[t,1] = {t+1, n+2-t} )
);
solve satisfy;
output[
"\(x[p,w])" ++ if w == nw then "\n" else "\t" endif | p in 1..np, w in 1..nw
]
Backend solver: Gecode
(Here's a summarize of my comments above.)
The range syntax is simply a shorthand for contiguous values in a set: 1..8 is a shorthand of the set {1,2,3,4,5,6,7,8}, and 5..6 is a shorthand for the set {5,6}.
The reason for this shorthand is probably since it's often - and arguably - easier to read the shorthand version than the full list, especially if it's a long list of integers, e.g. 1..1024. It also save space in the output of solutions.
For the two set versions, e.g. {1,2}, this explicit enumeration might be clearer to read than 1..2, though I tend to prefer the shorthand version in all cases.
I am trying to find all indices in an array A, where the value larger than time0 and less than time1. In matlab I can do:
[M,F] = mode( A((A>=time0) & (A<=time1)) ) %//only interested in range
I have something similar in IDL but really slow:
tmpindex0 = where(A ge time0)
tmpindex1 = where(A lt time1)
M = setintersection(tmpindex0,tmpindex1)
where setintersection() is function find the intersected elements between two arrays. What is the fast alternative implementation?
You can combine your conditions:
M = where(A ge time0 and A lt time1, count)
Then M will contain indices into time0 and time1 while count will contain the number of indices. Generally, you want to check count before using M.
This works (slight modification from mgalloy answer):
M = where( (A ge time0) and (A lt time1), n_match, complement=F, n_complement=ncomp)
The parenthetical separation is not necessary but adds clarity. n_match contains the number of matches to your conditions whereas the complement F will contain the indices for the non-matches and ncomp will contain the number of non-matches.
I am trying to build a calculator in abap. The requirements are:
Reads
two numbers (ex. 56.3 and 78.2)
a character from the following list: q, w, e, r, t
Displays the result of the operation specified by the character
Addition for character q
Subtraction for character w
Multiplication for character e
Division for character r
Exponent for character t
I have created a table with the operations that I am using in the calculator.
The problem is when I execute the program it only prints my last option (else) "the operation is not possible".
Here's the code I wrote:
REPORT Z_CALCULATOR_V2.
TABLES: ZOPERATII.
DATA result type p decimals 2.
DATA Q type c.
DATA W like Q.
DATA E like Q.
DATA R like Q.
DATA T like Q.
PARAMETERS Nr_1 type p decimals 2 OBLIGATORY.
PARAMETERS Nr_2 like Nr_1 OBLIGATORY.
PARAMETERS Operatie LIKE zoperatii-operatie OBLIGATORY.
if Operatie = Q.
result = Nr_1 + Nr_2.
elseif Operatie = W.
result = Nr_1 - Nr_2.
elseif Operatie = E.
elseif Operatie = R.
result = Nr_1 / Nr_2.
elseif Operatie = T.
result = Nr_1 ** Nr_2.
else.
WRITE 'The operation is not possible'.
endif.
write result.
if you change the data declarations to:
DATA Q type c value 'Q'.
DATA W type c value 'W'.
DATA E type c value 'E'.
DATA R type c value 'R'.
DATA T type c value 'T'.
the code should run as you expect. That said, you should read up on the documentation as suggested in the comments.
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}}