Newbie question: exporting a raw file from a 2D function

Question

I am new to Mathematica but I need to use it in order to create my datafile: I need very high precision that a standard C++ code cannot give me easily.

I have a 2D function that I will call myFunction[x_, y_] that is defined on x = [0 ; 4], y = [O ; 2]. This function is working perfectly, but now I need to create a raw file of this 2D function on 1024*1024 pixels encoded on double precision.

This is what I did for the moment:

output = Table[myFunction[i,j],{i,0,4,deltax}, {j,0,2,deltay}]
Export[CloudObject@"output.raw",output, "RAW"]

I got the following errors:

Cannot assign to raw object 1/128

Cannot assign to raw object 0

I am terribly lost, I didn't find any help for the moment on the Internet for this part.

Answer 1

You may try this

output = Table[myFunction[i, j], {i, 0, 4, 4/1023}, {j, 0, 2, 2/1023}];
img = Image[output, "Real64", ImageResolution -> 1024] 
Export["output", img, "RawBitmap"]

Set the type option of Image can produce a double-precision image. Notice that Mathematica does not support RAW image export, you can use RawBitmap, or just use BMP.