MATLAB: Calling Global value in a subroutine

global variable

I have a subroutine script that requires a value from the master.

The master has a global specifier and is tied to a separate variable which obtains the value.

Ie.

global ObsNum
ObsNum = ObsArrayRow

The assumed global variable ObsNum returns the correct value in the workspace of the Master script.

The subroutine script then opens and continues executing and where I have stipulated:

n = ObsNum

The following error is thrown in the workspace:

"Undefined function or variable 'ObsNum'.

Error in AffineTransformationV1_0 (line 81) n = ObsNum

Error in Report3MainV1_0 (line 811) AffineTransformationV1_0() "

Do I need to do anything more to call the global variable ObsNum?

Best Answer

You have to use global ObsNum inside your function also. You declare the global variable inside the function.

Related Solutions

MATLAB: Can any one please define or share link of affine model with six parameter to describe the image global motion?

An Affine transformation preserves parallel lines but not angles, and it is usually adopted as an approximation for projective transform when parallel lines almost preserve their parallelism. The model is based on 6 parameters and, since points at infinity stay at infinity while finite points remain finite points, we can assume that its transform is:

Where x, the 3 elements vector on the right, is expressed in 2D uniform coordinates with the last value equal to 1. While the output x' is in inhomogeneous coordinates. 3 corresponding 2D points between two images are sufficient to define the 6 parameters of the transformation and it can be considered a generalization of the scaling transform where the parameters are only 4 (1 for scaling, 2 for translation and one for rotation). The scaling transform:

An exemple for the affine transform is the following:

MATLAB: How to stop matlab automatically converting a normal variable into a global variable that I defined previously but deleted.

Variables declared in a script exist in the base workspace. However, variables declared inside a function only exist in the function workspace. In other words, they are destroyed when the function returns and you shouldn't see them in the base workspace unless:

The variables are declared global (using global is a bad practice, you should not declare global variables);
You are using the debugger and stopped during the execution of the function (in that case what you see is the function workspace);
The variables are outputted by the function into a script as in the following:

% Function file foo.m
function c = foo(a,b)
c = a + b;
end
% Script file script.m
clear all
close all
clc
c = foo(10, 12); % c is in the base workspace, because it was declared in a script

Could you copy and paste your function where you declare mog? If you want to learn more about functions and the scope of a variable, you can refer to the online documentation on functions .

Best Answer

Related Solutions

MATLAB: Can any one please define or share link of affine model with six parameter to describe the image global motion?

MATLAB: How to stop matlab automatically converting a normal variable into a global variable that I defined previously but deleted.

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