How to get this while cycle?

Hi, I'm trying to get a while cycle which checks convergence every iteration.

Within the cycle, I'm solving a system which returns each iteration 3 types of solutions: a (vector), B, C (matrices).

Subscript "0" is related to the (l-1) iteraton, the other refers to the (l) iteration.

I wrote this code:

while (abs(a_0-a) > 1e-6) & (abs(B_0-B) > 1e-6) & (abs(C_0-C) > 1e-6)
....
end

It starts, but it do only one iteration, I don't know why.

It should iterate until ALL residues are lower than 1e-6.

Probably it's wrong, maybe due to parentheses or logical operators. I've already tried to change them, but in the other cases it doesn't work.

What should I do?

Thank you for your help!!

Answer 1

[Fabio Freschi]

if B and C are matrices, make them vectors using :

while any(abs(a_0-a) > 1e-6) || any(abs(B_0(:)-B(:)) > 1e-6) || any(abs(C_0(:)-C(:)) > 1e-6)

[Elia Paini]

Great, it works! Thank you!

Answer 2

[Walter Roberson]

while (abs(a_0-a) > 1e-6) || (abs(B_0-B) > 1e-6) || (abs(C_0-C) > 1e-6)

[Elia Paini]

I got this error:

Operands to the logical and (&&) and or (||) operators must be convertible to logical scalar values.

[Walter Roberson]

while any(abs(a_0-a) > 1e-6) || any(abs(B_0-B) > 1e-6) || any(abs(C_0-C) > 1e-6)

[Elia Paini]

Same error

[Walter Roberson]

while any(abs(a_0-a) > 1e-6, 'all') || any(abs(B_0-B) > 1e-6, 'all') || any(abs(C_0-C) > 1e-6, 'all')

The implication is that at least one of your subtractions is giving back a matrix that is 2 or more dimensions.

Please check that a_0 and a, and B_0 and B, and C_0 and C, have the same orientation if they are vectors. For example,

    (1:3).' - (1:3)

is not the vector [0 0 0]

[Elia Paini]

I checked, the couples have the same dimension and orientation.

a_0 and a are (4x1), B_0 and B are (4x2), C_0 and C are (4x3)