I want to resample an array of elements using the command idresamp(). The input arguments for idresamp function is an array x. So I should get the output as an array. However, I am getting a structure iddata. I don't know how to access the elements /result of the resampling. Can somebody please show how to access the resampled values? Thank you.
x=rand(4000,1); %create some arbitrary data
x_resamp =idresamp(x,2); %resampling factor is 2
Here x_resamp is of iddata type. So, I am unable to access the result. On clicking the variable x_resamp this is what I got
How does one access the resampled values (output). Where is the array? The next step is to calculate the power after resampling and hence I need to use the resampled values.
I am using Matlab R2018a.
If you just want to resample by a factor 2, and have access to the Signal Processing Toolbox, use resample:
y = resample(x,2,1);
If you are insistent on using idresamp, you need to know that it returns an object of type iddata, which comes with a long documentation on usage. I think this complicates things more than you are looking for. It seems you should be able to do:
x_resamp = idresamp(x,2);
y = x_resamp.OutputData;
(but I can't test this because I don't have access to this toolbox.)
Related
I want to use Faster rcnn inception v2 to do object detection in tensorflow.js. But i can't find some method in tfjs like get_tensor_by_name and session run for prediction.
In tensorflow (python), the code as the following:
Define input and output node:
# Definite input Tensors for detection_graph
self.image_tensor = self.detection_graph.get_tensor_by_name('image_tensor:0')
# Definite output Tensors for detection_graph
self.detection_boxes = self.detection_graph.get_tensor_by_name('detection_boxes:0')
self.detection_scores = self.detection_graph.get_tensor_by_name('detection_scores:0')
self.detection_classes = self.detection_graph.get_tensor_by_name('detection_classes:0')
self.num_detections = self.detection_graph.get_tensor_by_name('num_detections:0')
Predict:
(boxes, scores, classes, num) = self.sess.run(
[self.detection_boxes, self.detection_scores, self.detection_classes, self.num_detections],
feed_dict={self.image_tensor: image_np_expanded})
Do anyone know how to implement those two part of code in tfjs?
Please help. Thank you!
You don't have a session.run function in tensorflow.Js as there is in Python. In python, you start defining a graph and in the run function, you execute the graph. Tensors and Variables are assigned values in the graph, but the graph defines only the flow of computation, it does not hold any values. The real computation occurs when you run the session. One can create many session where each session can assign different values to the variable, that is why the graph has a get_by_tensor_name which outputs the tensor whose name is given as parameter.
You don't have the same mechanism in Js. You can use the variable as soon as you define them. It means that whenever you define a new tensor or variable, you can print it in the following line whereas in python, you can only print the tensor or variable only during a session. The get_by_tensor_name does not really have a sense in Js.
As for the predict function, you do have one in Js as well. if you create a model using tf.model or tf.sequential, you can invoke predict to make a prediction.
How to use an step function for an array in Anylogic?
step function is applied to double values, but I want to applied on elements of an array at a specific time.
You can't... so this is a solution:
Instead of an array you should use a linkedHashMap where your key is the specific time and the element is the step value you want at that time. So you defined it as follow:
And you put the values like this:
stepsArray.put(3.0,2.3);
where 3.0 is the time in which the step will occur and 2.3 is the value the step will take. You have to put there all the values you need. You are the one who has to fill these values according to your needs.
Then you create an cyclic event that will evaluate if it's time to apply a step and you create a variable of type double that will be the one storing the value of the step.
So, the event:
double theTime=round(100*time())/100.0;//it's better to round up the time just in case
if(stepsArray.containsKey(theTime)){
variable=stepsArray.get(theTime);
}
note that I'm using a variable, not a dynamic variable.. they you can connect the variable to wherever your step is needed in the sd model.
This method is a bit complicated, but it's the most general for your completely ambiguous question.
Not sure Felipe's approach is the best one but maybe I misunderstand the question.
Have you tried using a "table function" object? Define it as below where the horizontal axis represents the time unit and the vertical your step function data:
Then, use a cyclic event that every relevant time unit (depends on your model) pulls the current required value from the table function:
I have the following nested struct:
hole 1x200 struct, diam 1x12 struct, which has the following fields: pos, freq1, fre12
That is:
hole(1 to 200).diam(1 to 12).pos
.freq1
.freq2
From a value (freq1 and freq2), I would like to obtain the field name of the struct. So I will need to find the value that matches with freq1 and freq2 and show the fieldname.
I tried to use structfun in order to apply a function to each field.
[struct.field]=structfun(#(x) find(x.freq1==27.059783995484867 & freq2==76.468355874897000))
But I guess I am writing something wrong on the code.
Also I create an anonymous fuction but I have the following error:
'Error using structfun / Inputs to STRUCTFUN must be scalar
structures'
. How ever when I verified if an specific value of the struct is scalar, I have a positive answerd: isscalar(hole(130).diam(10))
I belive I more near the solution using this script:
myfun=#(yourarray,desiredvalue) yourarray==desiredvalue;
%//Apply function to each field of scalar structure, it SCALAR??
desiredfieldindex=myfun(structfun(#(x) x,hole),26.697046257785030)
desiredFieldName=fNames(desiredFieldIndex)
I don´t know if I am in the rigth path, or I should utilize the function find. ALso I that case I don´t know how to implement it.
Couple of things.
FLOATING POINT VALUES! Careful!! Never compare a floating point value as val==0.3! do abs(val-0.3)<10^-8 or something similar. Read more here.
You are using structfun wrong. The function needs 2 arguments, and you are just passing 1! However, structfun will apply a function to each field so you are not using it rigth either in that sense. Lets see an example
example:
a.hithere=5;
a.notthis=3;
fun=#(x)x==5;
[isfive]=structfun(fun,a)
isfive =
1
0
As you can see, it applies the function to each of them. If you try to change the function to fun=#(x)x.hithere==5 you will get an error! As the function is applied to each field, and x.hithere.hithere or x.notthis.hithere do not exist.
If you want to check both values, you will need to check them independently making two separated calls to structfun or avoiding structfun and just making a for loop.
What is the equivalent of the following for a C-mex s function? That is, how do I set discrete sample time of a block to the top level fixed step size in C?
My problem is, I could not find a way to "get" the top level fixed step size parameter in C-mex.
function setup(block)
block.SampleTimes = [str2double(get_param(bdroot, 'FixedStep')) 0];
Use ssGetFixedStepSize to get the base rate of the model. You may also want to ssSetErrorStatus if the that call returns 0, because that means your model is not configured with a FixedStep solver.
If, for some reason, you really want to go about fetching the information similar to what you have in the question, then you might be able to get access to it if you dig through the SimStruct pointer's fields. To do this, breakpoint in the mex file using a debugger and watch that variable.
Another option would be a few mexCallMATLAB calls to get the information you want.
I am using OpenGL to create a nurbs surface (gluNurbSurface(...)) and I would like to know how reach the normal value to the control points(black dot) to the surface market as a red dot. With this information I will be able to calculate the distance between them.
Added
In order to get another answers or improve the subjected I would like to write part of the code, I hope can get more help:
In this part you can observe how I initialize the nurbs.
init_surface();
theNurb = gluNewNurbsRenderer();
gluNurbsProperty(theNurb, GLU_SAMPLING_TOLERANCE, 50.0);
gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_FILL);
gluNurbsCallback(theNurb, GLU_ERROR,
(GLvoid (*)()) nurbsError);
Next the surface is created with their parameters.
gluBeginSurface(theNurb);
gluNurbsSurface(theNurb,
U+ordenU, knotsU,
V+ordenV, knotsV,
V * 3,
3,
&ctlpoints[0][0][0],
ordenU, ordenV,
GL_MAP2_VERTEX_3);
gluEndSurface(theNurb);
Remember I am using C. And in this moment I am trying to introduce the values of the nurbs into a vector with the function proposed by genpfault in the first answer but I do not know in which part I have to add them.
Set a GLU_NURBS_NORMAL_DATA callback via gluNurbsCallback(). A GLU_NURBS_VERTEX_DATA callback would also be useful.
Point *userData (via gluNurbsCallbackData()) at some sort of dynamic array data-structure to hold the points/normals. If you were using C++ I'd recommend a std::vector of Eigen::Vector3fs.