Error using fgets Invalid file identifier. Use fopen to generate a valid file identifier.

CODE

clear all; close all; clc

addpath('apm')

s = 'http://byu.apmonitor.com';

a = 'data_regression';

apm(s,a,'clear all');

apm_load(s,a,'model.apm');

csv_load(s,a,'data.csv');

apm_info(s,a,'FV','a');

apm_info(s,a,'FV','b');

apm_info(s,a,'FV','c');

apm_option(s,a,'a.status','1');

apm_option(s,a,'b.status','1');

apm_option(s,a,'c.status','1');

apm_option(s,a,'nlc.imode',2);

output = apm(s,a,'solve');

disp(output)

ERROR

Error using fgets

Invalid file identifier. Use fopen to generate a valid file identifier.

Error in apm_load (line 21)

aline = fgets(fid);

Error in Regression (line 10)

apm_load(s,a,'model.apm');

[Adam Danz]

Please share the code that generates the fid variable and share the value of fid.

[Voss]

@Adedotun Banjo: Are you using this File Exchange entry?

https://www.mathworks.com/matlabcentral/fileexchange/66468-model-predictive-control-and-estimation-with-arduino

Answer 1

[Voss]

Specify the file names as absolute or relative path names. That is, instead of specifying just the file name "model.apm", if "model.apm" is located in the "apm" directory, which is in the current working directory, you could say:

model_file_name = fullfile('.','apm','model.apm');

apm_load(s,a,model_file_name);

That's a relative path (relative to the current working directory). You could also use an absolute path, e.g.:

model_file_name = 'C:\Users\banjo\apm\model.apm'; % or wherever model.apm is on your computer

apm_load(s,a,model_file_name);

Similarly for other file names you need to specify.