the initialize computation to construct the server state - tensorflow-federated

In the federated learning context, and like this tutorial shows, initial weights of global model (at server level) are initialized randomly with : state = iterative_process.initialize(). I want to have the hand to put these initial weights by downloading them from another model (load_model()). So please how can I proceed, I'm newer in TFF.
Thanks

You can either manually create a state object with the same structure and any values you choose, or use tff.structure.update_struct.
If you already have a my_model, and instance of either tff.learning.Model or a tf.keras.Model with weights you want, you can write something like
state = tff.structure.update_struct(state, model=tff.learning.ModelWeights.from_model(my_model))

Related

How to define collision filter groups across model instances?

When constructing a MultiBodyPlant from multiple ModelInstances each loaded from a separate URDF, is there a way to define collision filter groups to exclude collisions across model instances? In the multibody URDF parser, loading collision filter groups is restricted to the those present in the same model instance.
What I would like to do is in URDF A specify:
<drake:collision_filter_group name="model_a_group">
<drake:member link="link1"/>
<drake:member link="link2"/>
<drake:ignored_collision_filter_group name="model_b_group"/>
</drake:collision_filter_group>
and in URDF B specify:
<drake:collision_filter_group name="model_b_group">
<drake:member link="link4"/>
<drake:member link="link5"/>
<drake:ignored_collision_filter_group name="model_a_group"/>
</drake:collision_filter_group>
But currently attempting to do this results in the following error:
abort: Failure at multibody/parsing/detail_urdf_parser.cc:238 in abort:
Failure at multibody/parsing/detail_urdf_parser.cc:238 in ParseCollisionFilterGroup():
condition 'collision_filter_group_b != collision_filter_groups.end()' failed.
The scope of drake:collision_filter_group is limited to the scope of the file. So, it's sufficient to prevent "fake" collision at a robot's joints but insufficient to prevent two robots that get parsed independently from colliding.
In order to achieve that end, you'll have to parse the two robots, and then algorithmically declare the collision filters.
I don't have a great deal of time right now, so I'll give a rough overview of what it looks like, and then provide code when I free up later:
The approach.
Parse both URDFs (SDFs).
Grab the bodies for model instance "a" (link1 and link2), and similarly the bodies for model instance "b" (link4 and link5).
Using the MBP interface get the geometry::FrameId associated with each of those bodies. (We'll call them frameA1, frameA2, frameB4, frameB5, respectively.
Create two instances of geometry::GeometrySet. geometry_set_A = {frameA1, frameA2} and geometry_set_B = {frameB4, frameB5}.
Invoke SceneGraph::ExcludeCollisionsBetween(geometry_set_A, geometry_set_b).
Done
This should give you the first glimmer of how to proceed. I'll come by for a second pass to give concrete code to accomplish the task later.

Filtering Smarttables initial read request

im using a sap Smarttable to display my data from an ABAP Backend server. Additionally im using SmartVariantManagement to apply Variants and make them persistent.
The problem in my Application is the initial Load of the Smarttable. It seems like the table is first loading all the available data without any filters from the inital Variant of my Smartvariantmanagement.
Is there any way to apply the filters of Smartvariantmanagement to the initial Load in the Smarttable?
Or even better: Is it possible to shut down a running odata-read request if i apply a new selection in the smartfilterbar and just run the new one instead?
example 1:
you can avoid the initial request by the smarttable property
enableAutoBinding="false"
you can also set some mandatory fields for filtering, now the user performces an explicit call to the database
example 2:
you can also define a filter in the smarttable function
beforeRebindTable="onBeforeRebindTable"
controller:
onBeforeRebindTable: function (oEvent) {
var oBindingParams = oEvent.getParameter("bindingParams");
oBindingParams.filters.push(new sap.ui.model.Filter("PropertyX", "EQ", "myProperty"));
}
regards

Operations on a stream produce a result, but do not modify its underlying data source

Unable to understand how "Operations on a stream produce a result, but do not modify its underlying data source" with reference to java 8 streams.
shapes.stream()
.filter(s -> s.getColor() == BLUE)
.forEach(s -> s.setColor(RED));
As per my understanding, forEach is setting the color of object from shapes then how does the top statement hold true?
The value s isn't being altered in this example, however no deep copy is taken, and there is nothing to stop you altering the object referenced.
Are able to can alter an object via a reference in any context in Java and there isn't anything to prevent it. You can only prevent shallow values being altered.
NOTE: Just because you are able to do this doesn't mean it's a good idea. Altering an object inside a lambda is likely to be dangerous as functional programming models assume you are not altering the data being process (always creating new object instead)
If you are going to alter an object, I suggest you use a loop (non functional style) to minimise confusion.
An example of where using a lambda to alter an object has dire consequences is the following.
map.computeIfAbsent(key, k -> {
map.computeIfAbsent(key, k -> 1);
return 2;
});
The behaviour is not deterministic, can result in both key/values being added and for ConcurrentHashMap, this will never return.
As mentioned Here
Most importantly, a stream isn’t a data structure.
You can often create a stream from collections to apply a number of functions on a data structure, but a stream itself is not a data structure. That’s so important, I mentioned it twice! A stream can be composed of multiple functions that create a pipeline that data that flows through. This data cannot be mutated. That is to say the original data structure doesn’t change. However the data can be transformed and later stored in another data structure or perhaps consumed by another operation.
AND as per Java docs
This is possible only if we can prevent interference with the data
source during the execution of a stream pipeline.
And the reason is :
Modifying a stream's data source during execution of a stream pipeline
can cause exceptions, incorrect answers, or nonconformant behavior.
That's all theory, live examples are always good.
So here we go :
Assume we have a List<String> (say :names) and stream of this names.stream(). We can apply .filter(), .reduce(), .map() etc but we can never change the source. Meaning if you try to modify the source (names) you will get an java.util.ConcurrentModificationException .
public static void main(String[] args) {
List<String> names = new ArrayList<>();
names.add("Joe");
names.add("Phoebe");
names.add("Rose");
names.stream().map((obj)->{
names.add("Monika"); //modifying the source of stream, i.e. ConcurrentModificationException
/**
* If we comment the above line, we are modifying the data(doing upper case)
* However the original list still holds the lower-case names(source of stream never changes)
*/
return obj.toUpperCase();
}).forEach(System.out::println);
}
I hope that would help!
I understood the part do not modify its underlying data source - as it will not add/remove elements to the source; I think you are safe since you alter an element, you do not remove it.
You ca read comments from Tagir and Brian Goetz here, where they do agree that this is sort of fine.
The more idiomatic way to do what you want, would be a replace all for example:
shapes.replaceAll(x -> {
if(x.getColor() == BLUE){
x.setColor(RED);
}
return x;
})

Best alternative for 'long term' storing model-view-controller data in Objective-C/ios

I am planning on creating my app in a 'Model-View-Controller'(MVC)-style, and in the end, for me at least, this means that all data is stored in the controller-class. Let's say I have a class Player, and the player has several objects of class Weapons or Equipment or whatever. The initialization of Controller* stores the player(s), so if I can store/save only the Controller-object over time, even if the app or the device restarts, that would be nice. I did this in Java one, I put in Serialization = 100L;(or something like it) in the top of the file of every object that would be included when saving the Controller-object, and it worked perfectly. Is this possible in ios/cocoa-touch/objective-c?
I have read and used Core Data (not very much), but that is just a database-table, sql?, which would have me extract every piece of information of every object?
For instance, if the object Player* has a member NSString *name;, I would have to save the actual string in Core Data, instead of saving the object of the player? Like, varchar.
If there is any way to store an entire custom object on the device for further use, I would very much like to know what it's called, and where I can read about it/tutorials.
Read up on the NSCoding protocol. You can make your object complient to it, then serialized it and save it to a file. Later you can restore it to the same state by using a decoder. For sure some other posts that cover this topic on SO.

Erlang and the records

What is wrong in this code?
I was expected "titi" in person.name but I still have "toto"!
More explicitly, how to modify a record in a function?
init1()->
S=#person{name="toto"}, %record creation and field setting
fct(S),
io:format("~s~n",[S#person.name]).
fct(R)->
R#person{name="titi"}. %record updating
You need to get a result of fct():
init1()->
S=#person{name="toto"}, %record creation and field setting
S2 = fct(S), % Get updated record
io:format("~s~n",[S2#person.name]).
fct(R)->
R#person{name="titi"}. %record updating
Bertaud, I think you are getting ahead of yourself a bit. You really need to understand the basics of immutability before you write any more code. (i.e. "variables" do not vary : you can only assign a value to them once.) I suggest you read the free online guide "Learn You Some Erlang For Great Good", at http://learnyousomeerlang.com/. The section that covers the basics of variables is http://learnyousomeerlang.com/starting-out-for-real#invariable-variables.
It is impossible to stress too much that all data in Erlang is immutable. So to do something like in your original question you need to modify it like #hdima did. The record is not updated but rewritten. In the same way there is no global data in Erlang, all data belongs to a process. This is even true of ETS tables as they basically behave like a process, albeit a built-in one without explicit communication.
So if you use the process dictionary or an ETS table the data itself can never be updated, only the dictionary/table. This means that to modify some data in the dictionary/table you basically have to:
"Read" the data
Update the data making new data
"Write" the new back into the dictionary/table
Without writing the new data back into the dictionary/table it will be lost, as your new data was.
Within fct(), you're not mutating the record, but you're returning a new value for the record, which needs to be used further. If you're calling fct(S), without handling the return value, then you'll lose that new value ("titi").

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