I have a bit array A[32][16].
I want to check if any of the lower index values have a certain pattern.
For eg.
A[1][8:0] may have that pattern A[2][8:0] may also have that pattern.
Any thing from A[31 - 0][8:0] may have that pattern. Is there a way to refer to all the higher index components in a single statement.
something like A[5'bxxxxx][8:0] ?
There is no syntax to select a non-contiguous set of bits from an array, packed or unpacked, in a single selection. If A is an unpacked array, you can use one of the array reduction methods to create an expression that might suit your needs.
if (A.or() with (item[8:0] == your_pattern) ) // if any match
if (A.and() with (item[8:0] == your_pattern) ) // if all match
If A is a packed array, you could use replication concatenation to match all
if ( {32{ {8'b?,your_pattern} } } ?== A )
Related
If I define my array like this:
array[_, 1..2] of J: A;
where J is a enum, what function can I use to get the length of the first dimension of A? The length function returns 14 (and states that it doesn't work for multiple dimensions). I had it hard-coded like so in my testing, but it won't always be 13:
constraint forall(row in 1..13)(S[A[row, 2]] >= C[A[row, 1]]);
The length function is really only meant for getting the number of elements. When you want the retrieve indexes of an array, you should instead use the index_set function. This returns the actual index set, which you can iterate over: i in index_set(A)
For multidimensional arrays there are specific functions for each index set of the array. For example, to get the first index set from a two-dimensional array (as in your code fragment) you can use the function index_set_1of2
I have a Matlab structure like this:
Columns.T21=6;
Columns.ws21=9;
Columns.wd21=10;
Columns.u21=11;
Is there some elegant way I can give the value and return the field name? For instance, if I give 6 and it would return 'T21.' I know that fieldnames() will return all the field names, but I want the fieldname for a specific value. Many thanks!
Assuming that the structure contains fields with scalar numeric values, you can use this struct2array based approach -
search_num = 6; %// Edit this for a different search number
fns=fieldnames(Columns) %// Get field names
out = fns(struct2array(Columns)==search_num) %// Logically index into names to find
%// the one that matches our search
Goal:
Construct two vectors from your struct, one for the names of fields and the other for their respective values. This has analogy to the dict in Python or map in C++, where you have unique keys being mapped to possibly non-unique values.
Simple Solution:
You can do this very simply using the various functions defined for struct in Matlab, namely: struc2cell() and cell2mat()
For the particular element of interest, say 1 of your struct Columns, get the names of all fields in the form of a cell array, using fieldnames() function:
fields = fieldnames( Columns(1) )
Similarly, get the values of all the fields of that element of Columns, in the form of a matrix
vals = cell2mat( struct2cell( Columns(1) ) )
Next, find the field with the corresponding value, say 6 here, using the find function and convert the resulting 1x1 cell into a char using cell2mat() function :
cell2mat( fields( find( vals == 6 ) ) )
which will yield:
T21
Now, you can define a function that does this for you, e.g.:
function fieldname = getFieldForValue( myStruct, value)
Advanced Solution using Map Container Data Abstraction:
You can also choose to define an object of the containers.map class using the field-names of your struct as the keySet and values as valueSet.
myMap = containers.Map( fieldnames( Columns(1) ), struct2cell( Columns(1) ) );
This allows you to get keys and values using corresponding built-in functions:
myMapKeys = keys(myMap);
myMapValues = values(myMap);
Now, you can find all the keys corresponding to a particular value, say 6 in this case:
cell2mat( myMapKeys( find( myMapValues == 6) )' )
which again yields:
T21
Caution: This method, or for that matter all methods for doing so, will only work if all the fields have the values of the same type, because the matrix to which we are converting vals to, need to have a uniform type for all its elements. But I assume from your example that this would always be the case.
Customized function/ logic:
struct consists of elements that contain fields which have values, all in that order. An element is thus a key for which field is a value. The essence of "lookup" is to find values (which are non-unique) for specific keys (which are unique). Thus, Matlab has a built-in way of doing so. But what you want is the other way around, i.e. to find keys for specific values. Since its not a typical use case, you need to write up your own logic or function for it.
Suppose your structure is called S. First extract all the field names into an array:
fNames=fieldnames(S);
Now define a following anonymous function in your code:
myfun=#(yourArray,desiredValue) yourArray==desiredValue;
Then you can get the desired field name as:
desiredFieldIndex=myfun(structfun(#(x) x,S),3) %desired value is 3 (say)
desiredFieldName=fNames(desiredFieldIndex)
Alternative using containers.Map
Assuming each field in the structure contains one scalar value as in the question (not an array).
Aim is to create a Map object with the field values as keys and the field names as values
myMap = containers.Map(struct2cell(Columns),fieldnames(Columns))
Now to get the fieldname for a value index into myMap with the value
myMap(6)
ans =
T21
This has the advantage that if the structure doesn't change you can repeatedly use myMap to find other value-field name pairs
I have a cell array of matlab.unittest.constraints and a cell array of values. I'd like to see if the values match the constraints (respectively). Of course, I can just use a for cycle, something like the following code:
satisfied = zeros(1,argLength);
for i=1:argLength
satisfied(i) = satisfiedBy(cons{i}, val{i});
end;
answer = all(satisfied);
but knowing MATLAB, there must be a way to condense all that into a single line, I just don't know it. I compare the lengths of the arrays beforehand and return false if they're not equal.
Here is a possible CELLFUN statement:
satisfied = cellfun(#satisfiedBy, cons, val);
Make sure satisfiedBy returns only single numeric/logical value.
I want to replace the value of the fields in a structure array. For example, I want to replace all 1's with 3's in the following construction.
a(1).b = 1;
a(2).b = 2;
a(3).b = 1;
a([a.b] == 1).b = 3; % This doesn't work and spits out:
% "Insufficient outputs from right hand side to satisfy comma separated
% list expansion on left hand side. Missing [] are the most likely cause."
Is there an easy syntax for this? I want to avoid ugly for loops for such simple operation.
Credits go to #Slayton, but you actually can do the same thing for assigning values too, using deal:
[a([a.b]==1).b]=deal(3)
So breakdown:
[a.b]
retrieves all b fields of the array a and puts this comma-separated-list in an array.
a([a.b]==1)
uses logical indexing to index only the elements of a that satisfy the constraint. Subsequently the full command above assigns the value 3 to all elements of the resulting comma-separated-list according to this.
You can retrieve that the value of a field for each struct in an array using cell notation.
bVals = {a.b};
bVals = cell2mat( bVals );
AFAIK, you can't do the same thing for inserting values into an array of structs. You'll have to use a loop.
My requirement is to match tags. In the example, this particular HourConstraint checks the TeacherHour assigned to Hour(23).
Specifically, it checks TeacherHour.attributes["tags"] for the values ["asst_ct","teacher_john_smith"] and detects atleast one match, two in this case (both "asst_ct" and "teacher_john_smith") .
TeacherHour:
id: 47
assigned_hour: Null
attributes:Map<List<String>>
"tags":["asst_ct","no_strenuous_duties","kinda_boring","teacher_john_smith"]
"another_attribute":[...]
HourConstraint:
hour: Hour(23)
attribute: "tags"
values_list: ["asst_ct","teacher_john_smith"]
Question: How do I detect the presence (true or false) of common elements between two lists?
Drools Expert has memberOf and contains, but they check a scalar vs a collection, never a collection vs a collection.
I see two potential ways:
introduce a function boolean isIntersecting(list,list) and tell Drools to use that for truth checking
Implement TeacherHour.attributes[] as a string instead of a list and HourConstraint.valueslist as a regular expression that can match that list
There are a few options. Most straight forward is to use the Collections class to do that for you:
rule X
when
$t: TeacherHour( )
HourConstraint( Collections.disjoint( $t.attributes["tags"], values_list ) == false )
...
If this is something you would use often in your rules, then I recommend wrapping that function in a pluggable operator, supported by Drools. Lets say you name the operator "intersect", you can then write your rules like this:
rule X
when
$t: TeacherHour( )
HourConstraint( values_list intersect $t.attributes["tags"] )
...
A third option, is to use "from", but that is less efficient in runtime as it causes iterations on the first list:
rule X
when
$t: TeacherHour( )
$tag : String() from $t.attributes["tags"]
exists( HourConstraint( values_list contains $tag ) )
...