Math'ca - Can't get a function to read in data

[TopCat]

SOLVED - Math'ca - Can't get a function to read in data

I'm trying to do a maximum likelihood estimation in Mathematica. My data was in a text file and I read it into a table. Each entry in the table is two values, like {{1,2},{3,4},...}. I have a 2D function, P[x,y] and when I try and evaluate at a data point, P[data[[1]]], for instance, it doesn't input the values. It just returns P[{1,2}] (with the data in this example).

Now, it works fine when the data and function are one-dimensional. So this tells me the data is not stored in a manner that the function can immediately use. The problem here is that for me to use the Max Likelihood function, I need the data to be in the proper format. The arguments for the ML function are ML[data,f,param], so it needs to enter the data into the function. So, is there a way I can make a table or list of {x,y} data that could possibly work in this scenario?

As an aside, there must be because an example of this ML uses multi valued data. I can't get it work with mine though. Argh!

Thanks thank thanks to anyone who can help!

 

[TopCat]

Okay, I managed to figure this one out, and get a bit of Mathematica skill in the process.

If P is my Poisson function, I had to remap it into another function like so:

i = MapAll[Function[w, Apply[P, w]], #] &;

where w is a place holder variable, Apply is a math'ca function that turns list elements into function arguments, and MapAll applies every subpart of the list element to the function. Now my function can crawl over all of the data in a table, or accept a single element as input.

 

[oswaler]

Hello, it seems like you are having trouble with the format of your data in Mathematica. There are a few things you can try to make sure your function can read in your data properly.

1. Make sure your data is in the correct format: Your data should be in a list or table format, with each entry being a list of two values. You can check this by using the function Dimensions[data] to see the dimensions of your data. If it is not in the correct format, you can use the function Table[data[],{i,Length[data]}] to convert it into a list of two values.

2. Use the correct syntax for your function: It seems like your function is in the form P[x,y], so when you want to evaluate it at a specific data point, you need to use the syntax P[data[[i,1]],data[[i,2]]] where i is the index of the data point you want to use.

3. Check the dimensions of your function: Make sure your function is able to handle two-dimensional data. You can check this by using the function Dimensions[P] to see the dimensions of your function. If it is not in the correct format, you can use the function Table[P[data[[i,1]],data[[i,2]]],{i,Length[data]}] to convert it into a list of values.

I hope these tips help you in getting your function to read in your data correctly. If you are still having trouble, please provide more information about your data and function so I can assist you further. Best of luck!